Calculate Solar Cost For Your Home - geni.us/solar_reviews Ecoflow Delta Pro: geni.us/smzZiC 8 AWG Wire (100 feet) - geni.us/BtgTNT 10 AWG Wire (100 feet) - geni.us/qAgIb 12 AWG Wire (100 feet) - geni.us/Haist Power Analyzer - Power Analyzer - geni.us/s86J Line Loss Calculator: geni.us/Hhxpk DISCLAIMER: This video and description contain affiliate links, which means that if you click on one of the product links, I’ll receive a small commission.
Did you ever look at those hybrid panels that produced hot water by cooling the panels with water? I think they were an Aussie or New Zealand firm. Their primary goal was to reduce degradation due to heat but the byproduct surpassed their expectations.
I'm a retired engineer. I can say with an informed opinion your science and testing are outstanding! Thanks for making this topic so simple to understand for everyone.
A retired engineer? Lmfao u do realize us actual.hard working blue collar.men hate engineers because they are stupid as can be... just pop the hood onnypur new truck and tell me unarent cussing a dumb fuckin engineer.. and thats with every trade ive done we all hate book smart engineers its really not much dofferent than a home inspector that knows nothing but knows it all
Your test is very simplistic. First off, the higher the voltage, the less your transmission losses. Somebody has said it already. You want to series your panels. Get the voltage as close to the max your MPPT can take. That means, that for the same wattage, your current will be much less. It is the current that dictates the size of your conductors. As long as your insulation is rated for the voltage. All the Solar specific cables and connectors I have found is rated for 1000volts. Your MPPT is nowhere near that. Its all in Ohm’s law. If you use panels in parallel, you will need to fuse each parallel string. And, probably diodes. It depends on the specific panel how many volts they can handle. The long and the short. Series is best.
@@tsclly2377 makes sense he'd want to stay in (legally speaking) low voltage when possible. it also depends on the local regulations. in some areas they may require anything over low voltage to be professionally installed. and yes I know the low V and high amp is much more of a fire risk. The laws tend to be quite dumb.
"Series is best." Yes and no. From a resistive loss point of view 'yes'. If you have (partial) shadowing over the day (trees, posts, corners etc.) the story may well be different and individual MPPT's may be the better solution.
Master electrician here. #2 , 4, or 6 Aluminum USE is less expensive than any of those you tested. I worked mainly with ground mounted panels and the lengths involved are a very serious issue. Go with at least 48 volt systems and layout to minimize lengths anywhere possible.
But also , aluminum isn’t as good in tropical climates, especially here on the big island of Hawaii, where we have heat, moisture, sulphuric acid, hydrochloric acid, and salt. Aluminum turns into aluminum oxide here at an astonishing rate. Copper is much less prone to corrosion.
I always see the suggestion for 24V batter or 48V battery, but at least in my research I don't see inverters sold to handle this, they usually say 12V... Can we use bigger battery anyway? Also Eco Flow Power station requieres the XT60 Solar Connector wires to connect to solar pannel wires. Does the XT60 solar connector wire need to be the same size as the XT60 solar connector wire?
If you put the same panels in series then your current would be halved and your line losses would be a quarter. Then it would matter much less what wire you use.
Agreed. This video should have included a series connection. Nobody is going to run in two parallel. I expect the results wouldn’t be as exciting with parallel though. Also, most aren’t doing 100 foot runs.
@@ryanyoder7573 The results are still valid. They show the effect of Voltage drop over a distance. 100 is a nice number. Also, 100' to a ground mounted array would not be odd. Not all rooftops are in direct sun.
@@ryanyoder7573 I will run five in parallel. My system is designed to be 12 volts, and the controller can't do 24v, even. I will be using a shorter, 4 gauge cable. It would be nice to have different design constraints.
*I did a HIGH VOLTAGE array and ran 12 ga wire for about 50 feet* When drawing over 3,000 watts there is not enough voltage drop to affect anything (maybe 1 volt max) However. I'm running a 330VDC system. So thats only a 10 amp draw on the wires 😁 My system can produce upmto 5000 watts but it rarely utilizes as high as 4kw and at 5k I'd still be just 15 amps My system is a 21S 2P
Total Amps and Wire Length are the controlling 2-factors. Short wire lengths allow smaller wire gauges. All this video proves it best to get a solar controller to handle as high VDC (48 VDC is better than 24 VDC which is better than 12 VDC) as possible (solar panels in series vs parallel) and keep amperage low as possible to the controller.
The losses in the circuit are determined by the resistance of the wire and the electric current according to the formula P = I^2 x R . If the voltage is multiplied by 2, the current required to supply the same power to the load will be divided by 2. Therefore, the loss in the wire will be divided by 4, allowing the use of a thinner and cheaper wire.
Using microinverters on the roof solves a lot of the design complexity of figuring out parallel vs series wiring of your panels, including what gauge wire to run. More important, they alleviate the issue of one panel being in shade taking down the output of a substantial part of the system. While the microinverters themselves add cost to an installation, they should save money in labor costs (assuming you are paying someone to install a system,) due to the simplicity of the wiring. You incur losses converting back to DC to charge a battery backup, to be sure. If you have short runs, no or very little shade, and are charging a battery with your solar, DC direct wiring is probably best. If, like me, you have areas of your roof that move in and out of shade during the day, long runs back to the battery and panel, microinverters are probably better overall - probably. That, and we don't actually SEE the sun in the winter for months at a time. First 10 days of the year this year we had 5 minutes of actual direct sun :D Basically, there are many ways to peel this banana, and everyone needs to find the right one for their situation :) Videos like this provide data to help make those kinds of decisions.
@@smarouchoc7300micro inverters are the bain of the industry. Enphase has worked the system to defend their optimizer/micro-inverter business territory. Making up requirements not even considered by other countries.m like "rapid shutdown". Micro-inverters assume the power will be fed to the grid not stored local. For my system they are completely useless even counterproductive. Grid tied is great if you want to sell power for a quarter and buy it later for a dollar. Unless you have shading, optimizers are a waste. I want my solar power to work if the grid fails.
20+ years off grid. You should keep your wire runs under 30 feet and 8 gauge for12 volt. 10 gauge for 24 volt and 12 gauge for 48 volt. You can reduce loss by moving the controller and inverter closer to the panels and use an inverter to run 110 AC to your home. A shed works for that. I recommend 24 volt in series and a run under 30 feet with 10 or 8 gauge wire for off grid.
A shed costs a lot more and is WAY more work than conduit and heavier gauge wire. Though a small enclosure for a combiner box at the panels is very practical, but the combiners are generally set up to be outdoors. So they don’t need a totally weather proof enclosure like an inverter and charge controller will. That makes a BIG difference in time money and effort. Plus, the batteries need excellent weather protection, and you don’t want your batteries a long distance from the inverter or your breaker box, or the end use point(s). So in my case I don’t put panels on my roof because that is a whole can of worms for installation and roof repairs/replacement short and long term. I have a nice exposed hill that I put my panels on and it is just simpler to run 4 AWG into a weather proof cement board cabinet close to the cabin with the controller/inverter/ batteries.
@@solarcabin the numbers from many experts disagree with you…4 gauge for 50 feet carrying 72 volts at up to 1980 watts from the panels…quite sufficient. And do you know that the wire gets thicker as the numbers go down? You keep mentioning 10 and 12 gauge..that is WAY smaller than 4 gauge…way smaller…
@@5400bowen Off Grid 20 years teaching people to install solar and yes I am very aware of how wire gauge works. You will still have loss at at any significant distance with that gauge.
We use 10ga wire in large systems where the wire is going hundreds of feet. No matter how many panels you put in series, the max amps is 8 amps, the limit of the panel itself. Amperage is the killer in line loss due to amperage squared times resistance, and the reason we jack the voltage way up. When doing the calculations remember the list for resistance is for 1000ft of wire.
You are doing it wrong. IEEE guidelines suggest that line loss (I-squared R) losses should not exceed 2% in solar systems. Our system is 2.5KW at about 130VDC input to the charge controller. The line run is about 60' which required #4 AWG to not exceed 2% loss.
Off topic: Noticed your shirt, and I own a 1958 house in south Florida that my parents bought new and I was raised in. Over the years, more so recently, every outlet in this house, or switch that's ever been upgraded, or replaced due to wear and tear, has been found to have been taped originally back in 1958 when the house was built. Not trying to start an argument, or anything, but just thought I'd throw that out there for grins and giggles... Good test in this video. Thanks.
Hahaha, don't worry I won't get worked up either way. I just made the shirt a while back because of a few videos I did in the past there were no shortage of passionate people on both sides of the argument.
Still a newby in the solar community and I'm not very smart. I really like your videos because you teach and explain things down on my level of understanding.
As the thickness of wire goes up, the cost increases exponentially. For something like this, I'd at least do the math on the alternative of running two hots and two neutrals of a thinner gauge wire vs one conductor of the thicker gauge. There are calculators on line that let you look at this alternative, e.g. how many strands of AWG X = 1 strand of AWG Y. Of course the best thing is to max the voltage and shorten the cable run as much as possible.
Thank you for sharing your insights on wire thickness and cost considerations for DIY solar kits. It's important to find the right balance between wire gauge and cost efficiency. Maximizing voltage and minimizing cable runs are indeed effective strategies. By the way, have you heard about the Segway Portable PowerStation Cube Series? It's a versatile and reliable power solution for outdoor enthusiasts and RV lovers. It offers massive capacity, powerful output, fast recharging, and comprehensive protections. Plus, it's designed with Segway's UltraSeal Technology for waterproof performance. Check it out if you're interested!
Why not keep the EcoFlow in a cabinet or shed 10ft away from the panels; then run A/C to the house at 120vac? The much higher A/C voltage 'line loss', will be able to run much farther and be negligible (a endless point of contention between Tesla and Edison).
Sadly, approx. 2/3 of grid power from our local utility companies is lost during transmission (but yes, customers are still paying for the full 100%). With Solar on your own rooftop there is hardly any loss with appropriate wire size.
@@acordia91 Average grid losses are only around 5%, not 66%. The reason is because those overhead wires are running at much, much higher voltages. The basic trade-off is: double the voltage, halve the current, power losses over the wire wind up being only 1/4 rather than 1/2 because you aren't only reducing the current, you are also doubling the voltage. The reason it works like this is because wire losses result in a voltage drop based on (current x resistance). But POWER losses are a function of (current x voltage) and not only did you halve the current, you also doubled the voltage so even though the voltage drop is only halved, POWER losses are 1/4th rather than 1/2 because that voltage drop is relative to a doubled voltage.
20+ years off grid. You should keep your wire runs under 30 feet and 8 gauge for12 volt. 10 gauge for 24 volt and 12 gauge for 48 volt. You can reduce loss by moving the controller and inverter closer to the panels and use an inverter to run 110 AC to your home. A shed works for that. I recommend 24 volt in series and a run under 30 feet with 10 or 8 gauge wire for off grid.
On any solar system you should run the highest voltage your inverter can handle, as the higher the voltage the efficiency is much better on smaller wire. I can run a 6270 watt array at 466.5 volts at 13.44 amps. This allows me to run 100meters on 10awg with only a 2% voltage drop. All this means is the higher your voltage is the lower your resistance(aka amps).
Ive done real world tests and concluded that yes distance plus amps affects gains from thicker wire. But you want to consider average amperage not optimal. First of all, you will only get 80% of rated in best case. Second, thicker wire makes less difference when you need most efficiency- when its shaded and output drops to 30%...so optimizing for sunniest hours may not get you much over the whole year. That money may be better spent increasing your panels for cloudy winter days. Consider that for most overall yield per dollar.
Yes. Our solar systems from 1 to 20 megawatts in MA only consider 7 months of optimum solar. The other 5 months of winter are a bonus. And our 10ga wires run hundreds of feet from 500volts in 2013 to the 1200 volt systems now in 2024. The important thing for homeowners is to not cheap out and be sure they're using PV wire...and of course having a licensed electrician install the system. In MA only licenses can even touch solar.
@@Icehso140 Wow! At 500 volts (and even better 1200) the calculation shifts dramatically. Your professionals know what they are doing to bring up the voltage from the panels. People doing smaller systems should understand that three things affect the wire size calculation: the voltage (often 100 or less), the watts delivered (again, I think 80% rated or even lower to save $) and the distance. Again, I contend that you don't need to care so much about maximum efficiency on the best days of the year at noon. You need sufficient efficiency on the medium days that are more numerous in your area when the power produced will be good but less. Optimizing wire gauge for the the highest possible output that you only get when there's more sun than your system is designed for is not usually the best use of funds. Exceptions would be maybe running AC on the sunniest days or a grid-connected system that pays back. But good to recognize that seeing that 80% of panel rating may only happen for short periods and when you least need it. Might make more sense to spend that money on more panel for the shorter or cloudier days. Of course, it's an iterative process. More watts bigger wire...
@@ceeweedsl Thanks for the reply. I played with a battery backup/inverter setup for running my furnace for a few hours. Cost: one battery, 2500 watt pure sinewave inverter, battery switch...$700. Add 2 panels and charge controller...another $300. But I have nearly unlimited funds...as long as my wife doesn't see this. LOL But if someone can add a panel or two, it would be good, and Amazon has a pair of decent panels for less than $200. Buying used panels that are still good works to. Solar technology has increased efficiency times 3 over the last 10 years, and the panels we installed 10 years ago are still working within warranty. As they get switched out ,they become viable used panels for homeowner projects. (As long as a licensed electrician supervises the installation. )
Good info! Just to eliminate any doubt you should periodically series (butt to butt) test the accuracy of your meters. Probably no issues but you never know. Worked with this stuff for over 30 years. It happens.
Another way to calculate efficiency loss is the look up the resistance of your wire (and multiply by 2 for round trip resistance) or simply measure it with your ohm meter if you have one. Then, instead of the usual power calculation of volts times amps, you can also use resistance times amps squared. Use the amps number from the power monitor nearest to the panels and multiply by the resistance you measured (or obtained from Google). The lower currents that i observed in your measurements accounts for the lower than expected efficiency loss. If you repeated the test with the 2 panels wired in series, your efficiency losses would be half of what you measured for the parallel configuration. Because temperature voltage losses especially in the summer can have a confounding affect on power (and thus interfere with determining is the wire is the major culprit), you should use the Power = I (amps) X R^2 (ohms) equation when looking at wire losses. Conversely in the winter, the max voltage of the panel can be quite a bit higher than what the ratings are on the back of the panel, and thus also confound trying to see what the wire gauge affect is. Nice video! I also use 100 feet of 8 gauge when hooking up my portable panels.
Thanks for the video. Very interesting test. Ive always wanted to see that in the real world. However I would definitely be going for the 12 awg, especially if the runs are small and they very well could be, with Panels located directly above your Solar chargers. I dithered for ages, 18 years ago when I first installed my off the grid house worrying about the gauge of wire. Turns out line loss is the absolute least of your worries and is easily fixed. A couple of extra panels will cover any line loss. Wiring 12 gauge and higher is significantly easier than any of the lower numbers for a DIY. Anyone fought with Crimp lugs on fine stranded 8 gauge wire 😞 Having said that though... Cabling between your Batteries and Inverter should be as big as you can possibly get. Double them up if possible. That's where you will get the best value in your cabling. Your Inverter will love you for it.
Are you meaning run two leads instead of one when you say double them up? Or double the gauges? Because the first one is something I’ve been saying (and of course have known) for a long time. When I ran my Romex 75 feet from the post inverter breaker box, I did just that. Two ten amp wires can carry 20 amps, and connecting them at either end is perfectly fine. Imagine the multi strands inside insulation. It is the same thing. And better for heat dissipation. Nice clear correct info, by the way.
Yes running 2 leads to give you a great big lead is a great way to solve lack of instantaneous power. I had a problem with a 5KW inverter that had the recommended size battery leads that kept going into fault mode with any sudden large motor load. I doubled the Cables and the problem went away. Very easy to do in an existing installation as well because you can keep your down time to a minimum, and 2 smaller cables are normally cheaper and can give a larger square area of cable. In this situation I was looking at installing soft starts on the motors but didn't need to. (Still keen to try them out though, so I may still do one anyway) 🙂@@5400bowen
@@garyrussell5559 I also heard that electricity runs on the outside of wires, hence multi strand wire (did I already mention that about multi strand?). Two smaller wires have more surface area for that to happen. It never occurred to me that a double lead was better for high surge devices, seems peculiar. But like my brother said, electricity is magic! And you of course saw what I said about running two strands of Romex because it was rated at 50 feet at my power levels and it is a 75 foot run? The rest of your reply is so pleasantly accurate! Aloha from the big island of Hawaii!!
@@ceeweedsl Very true, and one of the most disappointing things you discover when completely Off Grid is that in Spring, summer and Autumn, your battery bank is normally fully charged before noon and the solar is pretty much dumped after that. In winter however I could triple the amount of solar panels and still struggle to charge my batteries on most days. My last array of solar panels I installed are completely for the winter sun and are almost upright. Panel angle lets you squeeze that last bit of current. I've found with Solar, when you miss, you tend to miss by a mile 🙂
It's quite a balancing act! The MPPT in the power bank will set the optimum VmP at the point of entry; the panels themselves will be at a lower VmP due to the voltage drop over the feed-wire system. This will mean that the panels will not be operating at their optimum MPP. Next, the power-bank will have a conversion efficiency curve for different DC input voltages; changing the input voltage due to the loss on the feed, will alter the efficiency, and how hot the MPPT gets. For my home DIY off-grid system I used short separate runs with the thickest wire I could afford, before the cost outweighed the benefit. From an engineer's point of view, efficiency is important; from the amateur's point of view, does it work?
In another video he had 4 panels in series going to the battery, and it was over the rated input voltage for the battery unit, so it would not charge. The unit blocked it. He had to reduce it to 3 panels in series to get it to accept a charge.
A reply I did to another’s comment: A shed costs a lot more and is WAY more work than conduit and heavier gauge wire. Though a small enclosure for a combiner box at the panels is very practical, but the combiners are generally set up to be outdoors. So they don’t need a totally weather proof enclosure like an inverter and charge controller will. That makes a BIG difference in time money and effort. Plus, the batteries need excellent weather protection, and you don’t want your batteries a long distance from the inverter or your breaker box, or the end use point(s). So in my case I don’t put panels on my roof because that is a whole can of worms for installation and roof repairs/replacement short and long term. I have a nice exposed hill that I put my panels on and it is just simpler to run 4 AWG into a weather proof cement board cabinet close to the cabin with the controller/inverter/ batteries.
From Leo: Look up whatever wire size that the charts recommend. The ampacity charts have been standardized since WWII. Don't forget to de-rate according to length and temperature if applicable. Then use 1 size thicker. That is how I sized conductors in industrial applications since the 1970's. Everything I set up is still running even in horrible conditions. Whatever you think you are saving today will always bite you in the long run.
You seem to be confused about ampacity vs voltage drop calculations. There are times when ampacity matters a lot, and so maybe that approach worked if you were pushing those limits more than voltage drop. An example would be short runs of high amperage, higher voltages. At that point voltage drop is out of the picture and ampacity is the limit. But for solar panel runs, not likely. An 8 ga will handle 40 amps and stay cool enough but that doesn't mean it's a good choice for 35 amps @ 12v over 300 feet. Nor is upsizing to 6ga adequate in that case. Use a Voltage drop calc and don't worry about ampacity in this usage.
I own a couple of meters similar to what you used. I've noticed what the meters show for the same source can vary a bit. This might contribute to at least some of the difference seen with the calculated values.
I think you are right. I am thinking about stepping up the testing equipment. Do you know of any higher quality power analyzers with a wide range of voltage and amperage capability?
@@everydaysolar For what I am doing, I couldn't justify more expensive meters, so I can't recommend anything. I did get some cheap "voltage reference" devices to test my meters, but they only go up to about 10 volts. Until you get better gear, you might try repeating the test with the meters swapped, then average the results.
@@everydaysolar Use A-B switching and operating conditions as stable as possible. Connect one device to the A side, note its results, swap to the B side, and note the results, swap back to the A side and note the results again, ensuring they read the same as before. If not, try again. Do this multiple times so you get at least three sets of good results at a given light level. Repeat at different light levels. Your records and a bit of work in Excel will allow you to cross-calibrate the two devices - "correct" the readings of the B device to match the A ( which you chose as the "standard").
Yes, when testing electrical values, it is best to repeat the test multiple times, pulling the test probes off and checking again. Rubbing them on the contacts as you watch the meter readings. A lot of electrical and electronics pros do it. False readings are quite common from faulty contact of the probes.
Solar wire comes in two flavors. 4mm2 or 6mm2. Both are rated for 50amps and 1000v and are tinned copper to stop the black death. Most inverters are rated at 16amps and 500v. They would have to be in series at 9amps per panel. Just keep connecting your panels until you hit the max Voc of 450v. 9amps and 450Voc. 4000watts per string. Some Charge Controllers MPPT will have 150v but 50amp. These are ok for short wire runs on DIY systems. Renogy Rover type chargers for RV's.
Great testing! You did mention a series configuration but you never tested it. The thing about going in series, which I don't think you mentioned, is that you cut your losses to 1/4, not just 1/2. So if you go back to that calculator and put in 12 AWG, 40V, 16A, 100ft, you get a loss of 15.8%. The equivalent series configuration would be 80V, 8A, and if you plug that in you get 1/4 of that: 3.95%. And that's with 12 gauge. For a whole-home system it is far better. Now you are running 240VAC with micro-inverters, or in the 400VDC range with a string inverter. The percentage losses with 12 gauge wind up being 1.32% @ 8A and 240VAC, or 0.79% @ 8A and 400VDC. This just goes to show, going for the highest possible supported voltage massively reduces wire losses. That said, I use 10 AWG for all my panel-side cabling. Actually it is even a bit thicker since it is 6mm^2 cable and 10 AWG is 5.3mm^2. I'm just a bit of a perfectionist. I just like the feel of the cable.
Thanks for the feedback and I would like to test a higher voltage as I agree that is a more practical and smart solution. The little power analyzers are pretty limited in the amount of voltage they can handle so that was the limiting factor for this test. I am thinking about stepping up to some mid-grade testing equipment which would expand the capabilities.
(this phenomena is also why people are moving away from 12V battery packs and to 48V battery packs for new ground-up builds. Because the losses and heat in the compartment at 48V are just 1/16th losses and heat at 12V). Now that 48V LFP battery packs are so easy to find.)
I've used No. 10 wire casually between 100 watt panels. The sum runs into heavy aluminum outdoor wire. 21 volts runs through long wires into regulators, one per battery set delivering 12 - 13 volts into lead batteries. The solar wires are long and the battery wires are short. No problems with efficiency.
@@andrew_koala2974 Through. The voltage loss between your solar panels and your charge controller means a lot less than between your controller and your battery.
You mentioned pros will be around 3-3.5% which sounds like a reference to NEC. Thats just a suggestion by NEC code. You should shoot for 1.2-1.5%. Can use 10 awg at close points to the array then in a combiner or JBox jump to an 8 or 6 for the long run to get to 1-1.5% drop. The lower the drop the healthier the system will operate ( most efficient)
The UnboundSolar calculator seems to be set up for AC current. AC current flows more towards the outside of the wire (skin effect) and doesn't make full use of the core of the conductor. DC current uses more of the copper in the wire and therefore has less loss. I think this effect could be contributing to the differences you see in your tests and what the calculator results show. I.e. the calculator will always overstate losses if you are using it for DC currents.
This is a common myth. Skin effect only starts being a thing at radio frequencies from around a few MHz and up. At 60 Hz it varies between zero and virtually indistinguishable from zero, so the full cross-section of the conductor is in play.
V = I x R. Higher the resistance, the higher the voltage drop across the cable. Since Power = V x I, as voltage goes down so does power at the power station. Yet another way to look at this is Power = V^2 / R. Even though R goes down with lower gauge wire runs, the reduced voltage (due to above) reduces by the square and the power delivery to your power station is lower.
HOWdy E-D-S, ... THANKS ... You just helped me JUSTIFY my usage of MARINE Grade "tinned" 8 AWG Pure Copper Wire from my FIVE arrays ... 6S / 5P Configuration = now 30 Panels ( eventually to be 6S / 6P configuration = 36 Panels ) ... to my ... All-In-One GROWATT SPF 6000T DVM-MPV INVERTER (about 75' length ) ... COOP ... the WiSeNhEiMeR from Richmond, INDIANA ...
100 feet is a long run. If you are building a system that uses more than just 1 40V panel, you can place the panels in series to increase the dc voltage, this will improve efficiency, but on the down side high DC voltage is a acing fire hazard. This is how the pros do it have hundreds of volts or the max the MPPT can take. If you what to be safe use 35mm2 or 50mm2 or 0 awg aluminum xlpe as the main trunk this will keep voltage drop down in a extra low voltage system, and aluminum cable is cheap. Be careful with you're terminations on aluminum thou.
Need to do this type of testing on a perfectly clear day. Additionally, always wire up your series/parallel solar system to give you the highest voltage acceptable for your inverter to get the lowest losses.
Why didn't you use the 4.53A in your calculator that your meter was showing? What I do is have a battery at solar panels with an inverter hooked up to it then use a normal 14ga outdoor extension cord to run power inside to charge house batteries.
Good to have some empirical data as well. I would suggest however that you do each of the tests twice and swap locations of the EcoFlow meters just to eliminate calibration differences in them.
It would be interesting to see how accurate the meters are. I was going to comment a similar idea, I have found I would rather like an existing comment then to duplicate a comment.
good show, but would have been good to let folks know that increasing panel voltage is a great way to reduce line losses (and therefore downsizing gauge of wire). This is the case since line losses are proportional to the SQUARE of current but only directly proportional to panel voltage.
Yeah, that would have been a good addition. I was keeping the voltage low for the power analyzer limitations so it was a bit misleading as compared to what you would setup in most real work applications.
What is actually been drawn heavily affects what the panels produce... You plugged into a battery... So it's state of charge will change production.... Should hook them up to a heating element through the mop, that will put a constant pull... And you will also see how hot the wires get as well when under heavy load.
I get that some of the calculators need help in their calculations, but the most important thing in sizing that you need to really worry about is the length of run, not the actual loss. A run of the wrong size for your configuration can/will result in a fire and that will be more of a worry than percentage of loss from wire size.
This is also why you should go as high voltage for the long cables as possible. I have a "off grid" 12v mppt inverter that accepts 56v input and i have open circuit voltage about 54v so there is little loss before the inverter. Also my "on grid" inverter have 470v input Always have as many panels in series as the inverter accepts (open circuit voltage, no load!)
I wrap all of my outlets in good tape. I'm a property manager and you wouldn't believe how many people remove outlet covers to put fancy ones on and then tell me how they go 'shocked'. Once a year at least. That may not sound like a lot but we also have a stainless steel back splash in the kitchens and that doesn't help. People will remove them when they move and put the cheap plastic ones back on... I will always wrap them. Not for my safety but for the non-electrical person who wants to open them up and change covers... I'll never get shocked because I shut the breakers off.
Don’t worry about the 15 amp limitation. Amps are "pulled" by the DP so there is no concern with being over 15.9 amps. The “maximum” of 15 amps is a limitation of what the Delta Pro can consume or take in itself. So even if the panels produce 20 or 25 amps, the Delta Pro will only take 15.9 amps. Think of the 15 amp outlets you have in your house. The breaker in your panel is rated at max of 15 amps but when you plug in a 100 watt light bulb into the outlet, the bulb doesn't pull 15 amps. The bulb only pulls the current it needs to operate the bulb which is what the DP does with the solar array power. However, volts are "pushed" so it is CRITICAL that the 150 volt limit of the DP is NOT exceeded under ANY circumstances after factoring in lowest panel operating temperatures. Most DP users look for panels with a VOC around 40 volts and connect them 3S or 3S2P or 3S3P or even 3S4P to be over panelled for less sunny conditions. Each of my arrays have a total of 3,240 watts but the DP caps the input at about 1,605 watts but it allows me to retrieve the full 1,600 watts for maximum amount of hours throughout the day.
Another option is to use micro inverters and convert to AC at the panels so you can use smaller wiring. The tradeoff is conversion loss so you need to determine which is worse, the line loss or the conversion loss.
The measured results don't match the calculator because the maximum amperage was used. Voltage drop increases as the load increases so, as has been mentioned, keep volts as high as your equipment can stand to minimize amps and voltage drop.
7:36 Your calculated loss (Column E) is percent "voltage" loss while your "watt-hour" loss (column D) is percent "energy" loss. You need to adjust one or the other to be identical units before directly comparing one with the other.
The calculators also are based on "temperature range". You are at an "ideal" temp. If you did the same test on a much hotter day you'd have much higher losses.
One other issue to consider on the wire sizes is that when a wire is run over a roof, the wire can retain heat from the roof and you loose some power there too. 10 awg would be minimum for me on a roof to compensate for the additional loss.
@@georgeperez4770 a valid thought. Or use white wire, or run it straight down as much as possible, or as I do with the cabins we build in Hawaii, use white roofing. But just look up videos on insurance and roofing companies reaction to roof mounted panels. When the roof needs replacing, yer gonna bleed hard. Some insurance companies have started refusing to insure homes with roof mounted panels…
With an eco flow delta pro, the max amperage you can get is 13A. The MPPT is not capable of taking any more. Further: Putting the Panels in Series (2x the voltage, 1/2 the current) will reduce the loss to 1/4 (3%for 12 AWG and 1.5% for 10AWG). Plus: The max Power you can get with 2x360W panels in parallel is 40,95Vx13A=532,35W The max Power you can get with 2x360W panels in series is 81,9x8,79A=720W
@@jacobpetersen5662 Thanks for the correction. The user manual I had when I wrote that comment, specified 13A, the current one specifies 15A. However, it does only slightly change the calculation (613,25W va. 532,35).
The current flow is what is charging the batteries. parallel panels allow for more current and faster charging times. The solar charge controller regulates the amount of current delivered to the battery it recharges. I
@@zaneenaz4962 Battery charges have a current regulator (something like a constant current regulator) Batteries are never charged directly using the PV voltage as it too high. the Battery charger will step down the voltage and supply higher current for the batteries. Basically it will use a Buck step-down converter will will drop the voltage and supply more amps than the PV panels can provide.
@@zaneenaz4962 Not really true. With an MPPT, what matters is POWER. The MPPT is a buck converter which will convert that power into current. If you have 2 panels of 10A each and 25V they can be wired in series as 50 V at 10A or in parallel as 25V and 20A. The POWER is the same either way: 500W. The MPPT will convert them both into the same number of Amps at whatever the battery voltage is (ignoring slight differences in efficiency at different voltages). Ignoring losses, that would be about 41A at 12V.
@@cccmmm1234 The power transfer is noted, but would you not also be increasing the resistance when the panels are in series? ....and the buck converter efficiencies are typically below 90% (another source of loss) As the systems scale up i suppose these loses drop off as lower percentage of the overall system. Leaves me to wonder if my 300W systems might not behave like your 500W.
I think some people might get the wrong idea. From the comments people are assuming that the fatter the cable the better. Which the answer is still yes but what if you have a small set up? If you have a smaller setup that has a lower power output with wires that don’t need to reach 50feet or 100feet getting a bigger wire can also cause power loss too? I’m talking about 13 amps 36 volts at a distance of 10 feet or so. Or am I wrong?
If you could datalog the voltage and amps through the testing period you'd be able to see why there is a difference between the online calculator and your measurements. What you want is the average value of the amps squared (amps * amps at each point) over the time interval. Take the square root of that [average current squared] number to get an "average" current value - and feed that back that into the online calculator. It will show a result that is a lot closer to your measurements. The growing difference in the loss % with each larger gauge wire is explained by the lower total Wh over each test interval. You would see the opposite trend in the closeness of the % loss number if you had a higher load for the 8AWG vs the 12AWG tests. Some rough calculations assuming a 40.5V constant system voltage (needs correction: all of your photos show actual voltage ~36-39V) show that if your trials were approximately 90 minutes for the 12AWG, 75 minutes for the 10AWG, and 80 minutes for the 8AWG - then the theoretical numbers from the online calculator match up. I think if you were able to fully load this system - receiving a constant 17.8A at 40.5V (721W) - the online calculator would be spot on versus your measurements.
When going for larger wire sizes (I will use 4 gauge) take care to avoid wire that is stamped 'CCA'. This is an acronym for Copper Clad Aluminum. You would have to upsize a wire gauge to get similar results. The number would get smaller - 2 gauge CCA instead of 4 ga. copper.
The amount of power running through a 4 ga CCA wire that we are referencing here... there is going to be negligible difference CCA vs OFC. Now if your running a 5000 watt stereo amplifer pulling current directly from the battery, then yeh OFC is a must have.
@@KingMrBigE nope - 500 watts of panels can be around 30 amps. Use the calculator and see for yourself. If you can tolerate more than 10% voltage drop, than I don't care either. Your charge controller adapts to the lower voltage, an amplifier can't. I just don't want to waste the precious power if I can avoid it.
If you simply default to a huge wire like that you are considered an electrical hack! Do what is correct and don't default to big wire as that is pure sloppy workmanship.
@@boblatkey7160 whoa. back off. I didn't default to anything. (5) 100 watt panels, 6 amps each, 12v, 30amps system. 20 feet of 4 gauge wire - you run that through the calculator. I prefer 3% voltage loss or less. THAT is good design.
Great video thanks so am I right in saying just use the thickest wire you can get? Maybe go to AWG 6 for achieve a lower loss than AWG 8 or are there other factors to consider and it’s not as simple as just the thicker the better? Also Rather than running separate wires is it just the same to run a 2 cable with both the wires in that cable. Thanks to anyone who can answer this in advance.
Here is my Theory, you did your Tests and its a great Explanation which made me think more about the "Wattage Loss" going into the Charge Controller, your "12AWG" wiring you lost 90.4 watts just from wire length and 32.7 watts from 10AWG, what if you reversed the setup, going from the Array with say under 10ft directly to charge controller, then have Inverter power line to be the 100' length pulling from stored capacity over to the home/off-grid cabin, then voltage drop or "Wattage Loss" would be reduced dramatically giving you better charging capabilities utilizing the most out of your solar panels. My Theory is if the Stored Energy in the batteries has voltage drop from the inverter wires to the house VS Array wires to Charge Controller/Batteries in the home, its just less power being taken from Stored Capacity and Technically the AH Stored is never lost from "Voltage Drop/Wattage-Loss" like it would be Entirely lost from the Array wires to Charge Controller. Let me know what you think, or possibly another Test lol
Interesting topic. By making measurements at the start of your cables and at the end of your cable you can narrow down to line losses, but you still need to consider the varying current flows. The 12awg starts with 12.9A and ends with 16.3A (why the wide range?).....the 10AWG starts with 4.7A and ends with 4.6A (more reasonable behavior). The greater the currents the greater the ohmic losses ! Line losses are lower with the lower currents. Having worked with different batteries i've noticed they draw power from the PV-panels differently, so the state of charge of your batteries should be considered.....they should be similar across both tests. The lower the state of charge the higher the current flow when using a PWM-type solar charge controller. Have not had an MPPT unit long enough to test this, but i still can imagine similar behavior. My inverter experiences make AWG and wire type a high priority ----> ua-cam.com/video/xK0L4dOMpSc/v-deo.html
Yeah, not a bad call out as a I think the 10 AWG test had a little more cloud cover and as such dropped the current resulting in a little less line loss than if the test had full sun. Overall I think the results are still valid within a reasonable error band.
And because the conditions differed, it invalidated the test. Current should have been equal and at the maximum design level to get accurate loss results. Cables will also have to be derated depending on how many cables are in the conduit and outside temperatures encountered, as all loss turns to heat and adds up, creating a safety issue if not considered. Is the conduit in direct sunlight, that's another thing to consider. Check the temperature rating of the cables as that needs to be considered also. Yes, there is a lot to consider for the DIY installer. @@everydaysolar
A small point. I noted the calculator you were using started 1 phase, that I would assume relates to AC current. My understanding is that losses are greater in AC circuits than the DC that the panels provide
There's a reason that high-tension power lines run much higher voltages than house current. And a somewhat related reason that AC dominates over DC, although DC can definitely be transmitted. If I was doing my house to replace grid power, I'd be looking at the storage devices available and trying to match the panels and the wiring to them for best effect, reliability, and longevity. And the copper wire probably (expensive as it is) would be a comparatively minor component of the cost. I'd likely favor the largest gauge practical, because the expense is one-time. Also, panels are necessarily outdoor, and need appropriate provision for electrical storms, which (I imagine) might be a relevant factor. Surely I'd want the advice of a competent engineer, either independently or with a trusted vendor; too many places to make mistrakes.
Number one problem that I see with this test is the wires appear to be exposed to the sun's heat. The heat from the sun will increase the resistance of the wires---making the voltage drop percentages higher. It is more likely that, especially for residential, the wires would be at least in conduit and most likely buried in the ground for most of the run. So, the drops would probably be less. However, the delta between the gauges would probably be in the same range as tested.
For a real world setup with the panels 100 ft. from the inverter, I imagine that the wires would almost certainly be in conduit underground, which would be a whole lot cooler than sitting on concrete in direct sunlight. I think that your test conditions probably made it appear that you needed a whole wire size larger than you would if the test were run underground in conduit.
For 100 feet even with this small two panel setup in parallel, I would go 4 or 6 gauge. Sure, costs a lot, but you pay for wire once, and it degrades over longer periods of time. But the losses are continuously reducing your power production, every minute of every day for years and years. Then there is durability and ability to add on. Add it all up.
So the best thing to do would be to Install an all weather Inverter like an SMA Sunny Boy close to the panels and A.C. to make the long runs to the point the power is needed. You have a lot less loss with AC vs. DC.
Should have put the 100 feet in the shade; hirer wires are also an efficiency loss. You mentioned the series connection, but didn’t test it. The higher voltage will be heaps more efficient and cheaper as you can use thinner wire. I’ll look for a series panel video now; I hope you did it already.
Upping the gauge of the cable increases the cable cost fast. It might be cheaper to run two separate cables, one for each panel of lighter gauges and combine them at the receiving end than to run one heavier one. And also, silicon & glass is cheaper than copper. If you have the space it might be feasible to install an extra panel to make up for the voltage drop rather than spending that (or more) money on a bigger cable. This also has an advantage of keeping the output higher under less favourable light conditions, where the current is lower anyway therefore the voltage drop is less of a factor. Of course if you can run the panels in series (if you have MPPT with an adequate maximum input voltage) then you massively reduce your losses. However, parallel has one significant advantage. In series, shade one panel and you wipe out the production of both. With a parallel setup one panel doesn't affect the output of the other. They can even be pointed in different directions to passively :"track" the Sun over the day. In series they must receive the exact same insolation.
If you were charging a battery there is absolutely no benefit from facing some panels in different directions. What you want is the maximum amount of amp hours delivered to the battery and that will only cut into that.
@@boblatkey7160 If that's *all* you are doing then that is probably the best way to go. However, if you are charging batteries and running loads all day and night, such as in an off grid household then things become quite different. Having some west facing panels makes a massive improvement to battery life because it lengthens the time each day the loads are purely solar powered, before dipping into the stored charge in the battery. It all depends on how large the solar array is and how big the battery is. 2 x 100 watts into a 100AH battery, for example, you probably want to point 'em the same direction.
The calculated losses are probably higher because they take into consideration temperature change of conductors exposed to heat accumulation either by heat generated by current or from heat from weather and the sun and enclosed conductors in conduit or hot attics. heat increases resistance and would increase amps.
I've heard that AC has less lose over longer distances than DC. With that in mind, would micro inverters be a good idea for solar panels that are far from the house?
Low current / high voltage will always be more efficient from a line loss perspective. This is why electrical utilities use high-voltage lines. P = V x I^2, so that current is exponentially more influential on the power loss of the system. The best scenario is to connect the panels in series if the design can handle it of course.
Of course, but this is surprisingly low current for the wire gauge! My larger array has 2 strings, 7x 72 cell panels in each one, a little under 400V on the string, but still has decent amperage in what I'm guessing is 8 gauge but can't remember anymore. 7.5amps per string likely by my calculation but I guess that's peak sun, so the top 1-2 hours of the day and the rest it's below that. Maybe not too bad afterall, but man, upping the copper thickness would likely pay for itself, everything else staying constant!
Have you ever heard of the Shoals Plug and Play cables/system? Can anyone judge whether it makes sense to use it? Although they seem to be a bit more expensive, they are extremely easy to use and no professional installer is required. Installation is also said to be very quick and more energy efficient than conventional cables. What do you think about that?
They have cool products but I have seen their use case more in the large solar farm application where you can get rid of combiner boxes with 1 massive wire that has a bunch of leads coming off to each string of panels. Which of their products were you considering?
The conclusion of the video is that for DIY solar projects, using 8 gauge wire significantly reduces line losses compared to 12 gauge and 10 gauge wires, with a loss of only 3.3% compared to the expected 6.9%. The video emphasizes the importance of choosing the correct wire gauge to minimize voltage drop and improve overall efficiency. It also suggests considering series and parallel configurations to optimize voltage and current for your specific setup. For larger projects, such as grid-tied systems, professional installation is recommended.
I keep mine under 2%. The tables are based on a temperature coefficient, high temperatures create more resistance, therefore more voltage will drop more. When the voltage drops the wire heats up giving you more resistance. Hence the voltage drops even further. Over time this can be a problem.
Silly test, because line loss per foot and current is all known and in online tables. They are very easy to use, so you can find out what your system line loss will be for each gauge wire. These test high line loses are because there is very high current flowing through the wire. In a real DC system, you want series wiring so you have as high a voltage as your inverter can handle. The current would be about 8 to 9 amps (whatever a single panel puts out). That will minimize your line loss. My 5 KW array uses two series strings, with 12 panels per string. Each string feeds it's own MPP inverter channel. That's about 430 volts at 8 amps, well within my grid-tie inverter specs. My line loss is minimal with 10 gauge wire.
I spotted a potential flaw in the testing. The Yunsailing 100V watt meter uses 12AWG wires. So it would automatically add 12AWG loss wherever you add it in the chain. I imagine for more accurate results you would need to resolder 8AWG wires to the Yunsailing, or get a higher quality meter such as the Powerwerx Watt Meter Plus, which uses 8 gauge wires with preinstalled SB50 Powerpole connectors.
Isn't the distance of those connections so short that the effect would be trivial? You also have to go with the AWG of the connections to the panel itself.
And now how much do you loose by not keeping your panels pointed into the sun? I think you can point the panels and get more than the wire losses. And by the way, it really dose not matter if the battery's are charged by 10 AM and you are not using much power during the day.
Great video, but I was wondering about the grounding wire from the solar panel frames to your main house grounding rod. What gauge should that be?? Thank you.
Sure, some. But any loss is consistent with each wire gauge tested so although the percentage losses shown might be slightly affected the overall message is the same. 8 is better than 10 is better than 12.
I think you should repeat the test with a constant DC input power supply, instead of a solar panel. Always control for as many variables as you can, to get the most scientifically reliable and repeatable result.
No. This is not a test of wire performance - thats already been done. It is a test with real world factors in the mix. Thats the next step for more nuanced understanding and decisions.
I'm more interested in wire sizes on batteries. I believe you need bigger wire on a 12v system, and a little smaller on 48v. I'd like to know what size to use on a 48v battery
Did you use a solar-to-xt60 Y adapter to connect the 8AWG wire to the EcoFlow? If so, does the adapter need to be the same gauge? I can't find an 8AWG Y adapter anywhere because the wire is so large. Is it OK to use a short 10AWG Y adapter with a long run of 8AWG wire? THX
Question: Have Rich solar panels with 12 AWG MC4 connectors. Thinking about using 8 AWG wires to a RV charge system. System will have 10 panels at 2x 100 watts connected in series / parallel, Panels @ 20V / 5A each= 40V / 25A total. Need information concerning connecting the 12 AWG MC4 to a 8 AWG MC4 or is that even a thing?
082723/2041h PST 🇺🇸. Thank you for the presentation on simple and adequate PV cells setup. Yes, it’s so true to venture out to connecting to 110AC system and automatic changeover switching, which is all too much for layman and myself ( electrical engineer) I have a similar set up 800W PV array and 2X12.80V@540Ahr LiFePo4 Battery, and 1200W inverter. All equipments are VICTRON. Here, in CA , we don’t experience load shedding or Blackouts. But it’s better to possess such a system, than not. I’ve watched your electrical systems wiring etc, a lot. Thanks again. Best wishes.
Great video and very informative. But there was one piece missing for me. If I go with the 8 gauge cable (my length is going to be about 100' to my ecoflow also), what about the XT60 connector from the 8 AWG (MC4 connector) to my XT60 connector, which only come in 10 gauge options. I cannot find an 8AWG MC4 to XT60 connector for my Ecoflow. Will having a 10 gauge 2' connection cable defeat my long 100' run of 8AWG wire?
Just came to mind I have 10 gauge, but at the connections, the wires are very, very small/thin gage , so does that reduce the 10 gauge down to these small wires?
That should not be a line loss issue since it is reduced for such a short length but you would want to make sure that thinner gauge can handle the current load from a failure/heat generation standpoint as opposed to an efficiency/line loss perspective.
Thank you for this video! A question, the analyzer you are using, I was wondering if it has the ability to record data points over an extended period of time? If it doesn't do you know of a similar solution for a similar price that does do that? Thank you!
This one will just continually record the active session (session starts when you plug it in) but is limited outside of this basic functionality. I think you could pull this data from the device through the serial port into a Raspberry Pi or similar device to provide much more functionality like plotting out the metrics over time.
Calculate Solar Cost For Your Home - geni.us/solar_reviews
Ecoflow Delta Pro: geni.us/smzZiC
8 AWG Wire (100 feet) - geni.us/BtgTNT
10 AWG Wire (100 feet) - geni.us/qAgIb
12 AWG Wire (100 feet) - geni.us/Haist
Power Analyzer - Power Analyzer - geni.us/s86J
Line Loss Calculator: geni.us/Hhxpk
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Did you ever look at those hybrid panels that produced hot water by cooling the panels with water? I think they were an Aussie or New Zealand firm. Their primary goal was to reduce degradation due to heat but the byproduct surpassed their expectations.
I'm a retired engineer. I can say with an informed opinion your science and testing are outstanding! Thanks for making this topic so simple to understand for everyone.
Thanks so much for the feedback 👍
A retired engineer? Lmfao u do realize us actual.hard working blue collar.men hate engineers because they are stupid as can be... just pop the hood onnypur new truck and tell me unarent cussing a dumb fuckin engineer.. and thats with every trade ive done we all hate book smart engineers its really not much dofferent than a home inspector that knows nothing but knows it all
Your test is very simplistic. First off, the higher the voltage, the less your transmission losses. Somebody has said it already. You want to series your panels. Get the voltage as close to the max your MPPT can take. That means, that for the same wattage, your current will be much less. It is the current that dictates the size of your conductors. As long as your insulation is rated for the voltage. All the Solar specific cables and connectors I have found is rated for 1000volts. Your MPPT is nowhere near that. Its all in Ohm’s law.
If you use panels in parallel, you will need to fuse each parallel string. And, probably diodes. It depends on the specific panel how many volts they can handle. The long and the short. Series is best.
You didn't watch the whole video. He said as much in the end.
He's trying to avoid the High(er) Voltage legal requirements.. you can laugh at my comment... 'electric fence' [just spike it through.]
@@tsclly2377 makes sense he'd want to stay in (legally speaking) low voltage when possible. it also depends on the local regulations. in some areas they may require anything over low voltage to be professionally installed. and yes I know the low V and high amp is much more of a fire risk. The laws tend to be quite dumb.
It's like Bell vs Tesla all over again!
"Series is best."
Yes and no.
From a resistive loss point of view 'yes'. If you have (partial) shadowing over the day (trees, posts, corners etc.) the story may well be different and individual MPPT's may be the better solution.
Master electrician here. #2 , 4, or 6 Aluminum USE is less expensive than any of those you tested. I worked mainly with ground mounted panels and the lengths involved are a very serious issue. Go with at least 48 volt systems and layout to minimize lengths anywhere possible.
what is No. 2, 4, 6 for a cross section?
@@jensschroder8214c’mon now…do a web search, don’t bother the man after he gave us words of true wisdom. Sincerely.
But also , aluminum isn’t as good in tropical climates, especially here on the big island of Hawaii, where we have heat, moisture, sulphuric acid, hydrochloric acid, and salt. Aluminum turns into aluminum oxide here at an astonishing rate. Copper is much less prone to corrosion.
I always see the suggestion for 24V batter or 48V battery, but at least in my research I don't see inverters sold to handle this, they usually say 12V... Can we use bigger battery anyway? Also Eco Flow Power station requieres the XT60 Solar Connector wires to connect to solar pannel wires. Does the XT60 solar connector wire need to be the same size as the XT60 solar connector wire?
@@adivasworld7466victron makes several 24 and 48 volt inverters, along with several other manufacturers.
If you put the same panels in series then your current would be halved and your line losses would be a quarter. Then it would matter much less what wire you use.
Agreed. This video should have included a series connection. Nobody is going to run in two parallel. I expect the results wouldn’t be as exciting with parallel though. Also, most aren’t doing 100 foot runs.
@@ryanyoder7573 The results are still valid. They show the effect of Voltage drop over a distance. 100 is a nice number. Also, 100' to a ground mounted array would not be odd. Not all rooftops are in direct sun.
@@steveurbach3093 yes they are valid they are just way more compelling due to the low voltage used which produces a high drop
@@ryanyoder7573 I will run five in parallel. My system is designed to be 12 volts, and the controller can't do 24v, even. I will be using a shorter, 4 gauge cable.
It would be nice to have different design constraints.
@@jamesalles139Don’t forget to fuse EACH panel if you wire them in parallel! Fuse rating is the one written on the panel labels.
*I did a HIGH VOLTAGE array and ran 12 ga wire for about 50 feet*
When drawing over 3,000 watts there is not enough voltage drop to affect anything (maybe 1 volt max)
However. I'm running a 330VDC system. So thats only a 10 amp draw on the wires 😁
My system can produce upmto 5000 watts but it rarely utilizes as high as 4kw and at 5k I'd still be just 15 amps
My system is a 21S 2P
Total Amps and Wire Length are the controlling 2-factors. Short wire lengths allow smaller wire gauges. All this video proves it best to get a solar controller to handle as high VDC (48 VDC is better than 24 VDC which is better than 12 VDC) as possible (solar panels in series vs parallel) and keep amperage low as possible to the controller.
I think most marine equipment are also 48 V .. so it opens up appliance options that avoid conversion to 120VAC which means even less losses
The losses in the circuit are determined by the resistance of the wire and the electric current according to the formula P = I^2 x R . If the voltage is multiplied by 2, the current required to supply the same power to the load will be divided by 2. Therefore, the loss in the wire will be divided by 4, allowing the use of a thinner and cheaper wire.
@@nathanneimansweet. Thanx.
Using microinverters on the roof solves a lot of the design complexity of figuring out parallel vs series wiring of your panels, including what gauge wire to run. More important, they alleviate the issue of one panel being in shade taking down the output of a substantial part of the system. While the microinverters themselves add cost to an installation, they should save money in labor costs (assuming you are paying someone to install a system,) due to the simplicity of the wiring. You incur losses converting back to DC to charge a battery backup, to be sure. If you have short runs, no or very little shade, and are charging a battery with your solar, DC direct wiring is probably best. If, like me, you have areas of your roof that move in and out of shade during the day, long runs back to the battery and panel, microinverters are probably better overall - probably. That, and we don't actually SEE the sun in the winter for months at a time. First 10 days of the year this year we had 5 minutes of actual direct sun :D Basically, there are many ways to peel this banana, and everyone needs to find the right one for their situation :) Videos like this provide data to help make those kinds of decisions.
@@smarouchoc7300micro inverters are the bain of the industry. Enphase has worked the system to defend their optimizer/micro-inverter business territory. Making up requirements not even considered by other countries.m like "rapid shutdown".
Micro-inverters assume the power will be fed to the grid not stored local.
For my system they are completely useless even counterproductive.
Grid tied is great if you want to sell power for a quarter and buy it later for a dollar.
Unless you have shading, optimizers are a waste.
I want my solar power to work if the grid fails.
20+ years off grid. You should keep your wire runs under 30 feet and 8 gauge for12 volt. 10 gauge for 24 volt and 12 gauge for 48 volt. You can reduce loss by moving the controller and inverter closer to the panels and use an inverter to run 110 AC to your home. A shed works for that.
I recommend 24 volt in series and a run under 30 feet with 10 or 8 gauge wire for off grid.
A shed costs a lot more and is WAY more work than conduit and heavier gauge wire. Though a small enclosure for a combiner box at the panels is very practical, but the combiners are generally set up to be outdoors. So they don’t need a totally weather proof enclosure like an inverter and charge controller will. That makes a BIG difference in time money and effort. Plus, the batteries need excellent weather protection, and you don’t want your batteries a long distance from the inverter or your breaker box, or the end use point(s). So in my case I don’t put panels on my roof because that is a whole can of worms for installation and roof repairs/replacement short and long term. I have a nice exposed hill that I put my panels on and it is just simpler to run 4 AWG into a weather proof cement board cabinet close to the cabin with the controller/inverter/ batteries.
@@5400bowen You are still going to have significant loss at any long distance with 4AWG.
@@solarcabin the numbers from many experts disagree with you…4 gauge for 50 feet carrying 72 volts at up to 1980 watts from the panels…quite sufficient. And do you know that the wire gets thicker as the numbers go down? You keep mentioning 10 and 12 gauge..that is WAY smaller than 4 gauge…way smaller…
@@5400bowen Off Grid 20 years teaching people to install solar and yes I am very aware of how wire gauge works. You will still have loss at at any significant distance with that gauge.
The Gauge of wire has absolutley nothing to do with voltage, using that as a method to size a conductor is a dangerous road to walk.
We use 10ga wire in large systems where the wire is going hundreds of feet. No matter how many panels you put in series, the max amps is 8 amps, the limit of the panel itself. Amperage is the killer in line loss due to amperage squared times resistance, and the reason we jack the voltage way up. When doing the calculations remember the list for resistance is for 1000ft of wire.
You are doing it wrong. IEEE guidelines suggest that line loss (I-squared R) losses should not exceed 2% in solar systems. Our system is 2.5KW at about 130VDC input to the charge controller. The line run is about 60' which required #4 AWG to not exceed 2% loss.
Does this guy have a second channel? I swear he looks like someone that does a lot of handyman stuff, outlets, wiring, etc.
Yep, this is my second channel and Everyday Home Repairs is the bigger one for sure.
This is a subject that doesn’t get covered often enough, nor with your great real world hands on demonstrations. Bravo!!
Off topic: Noticed your shirt, and I own a 1958 house in south Florida that my parents bought new and I was raised in. Over the years, more so recently, every outlet in this house, or switch that's ever been upgraded, or replaced due to wear and tear, has been found to have been taped originally back in 1958 when the house was built. Not trying to start an argument, or anything, but just thought I'd throw that out there for grins and giggles... Good test in this video. Thanks.
Hahaha, don't worry I won't get worked up either way. I just made the shirt a while back because of a few videos I did in the past there were no shortage of passionate people on both sides of the argument.
Still a newby in the solar community and I'm not very smart. I really like your videos because you teach and explain things down on my level of understanding.
Thanks. Running in series has its benefits given the cost of copper wire.
Yeah, Series is usually my default 👍 if possible.
As the thickness of wire goes up, the cost increases exponentially. For something like this, I'd at least do the math on the alternative of running two hots and two neutrals of a thinner gauge wire vs one conductor of the thicker gauge. There are calculators on line that let you look at this alternative, e.g. how many strands of AWG X = 1 strand of AWG Y. Of course the best thing is to max the voltage and shorten the cable run as much as possible.
Why does this guy look like Johny sins?
Thank you for sharing your insights on wire thickness and cost considerations for DIY solar kits. It's important to find the right balance between wire gauge and cost efficiency. Maximizing voltage and minimizing cable runs are indeed effective strategies. By the way, have you heard about the Segway Portable PowerStation Cube Series? It's a versatile and reliable power solution for outdoor enthusiasts and RV lovers. It offers massive capacity, powerful output, fast recharging, and comprehensive protections. Plus, it's designed with Segway's UltraSeal Technology for waterproof performance. Check it out if you're interested!
This is why I chose an EG4 inverter. it can handle 500 volts mppt. so the amperage is 10 or less.
All over the cost of 30-40 feet of wire?
I'm a new DIY solar player. This video helped me know that wire gauage matters. Thank you.
We are here to help 👍
I tell you the bigger the better, but in terms of wire thicknes not gauge
Why not keep the EcoFlow in a cabinet or shed 10ft away from the panels; then run A/C to the house at 120vac? The much higher A/C voltage 'line loss', will be able to run much farther and be negligible (a endless point of contention between Tesla and Edison).
There are so many different application that a longer run could be needed. If you can keep it short that would be preferred for sure.
Interesting results. I knew the 8 awg would be better, but I didn't expect that big of a difference. Thanks!
You bet!
Sadly, approx. 2/3 of grid power from our local utility companies is lost during transmission (but yes, customers are still paying for the full 100%). With Solar on your own rooftop there is hardly any loss with appropriate wire size.
@@acordia91 Average grid losses are only around 5%, not 66%. The reason is because those overhead wires are running at much, much higher voltages. The basic trade-off is: double the voltage, halve the current, power losses over the wire wind up being only 1/4 rather than 1/2 because you aren't only reducing the current, you are also doubling the voltage.
The reason it works like this is because wire losses result in a voltage drop based on (current x resistance). But POWER losses are a function of (current x voltage) and not only did you halve the current, you also doubled the voltage so even though the voltage drop is only halved, POWER losses are 1/4th rather than 1/2 because that voltage drop is relative to a doubled voltage.
20+ years off grid. You should keep your wire runs under 30 feet and 8 gauge for12 volt. 10 gauge for 24 volt and 12 gauge for 48 volt. You can reduce loss by moving the controller and inverter closer to the panels and use an inverter to run 110 AC to your home. A shed works for that.
I recommend 24 volt in series and a run under 30 feet with 10 or 8 gauge wire for off grid.
@@acordia91nice observations.
On any solar system you should run the highest voltage your inverter can handle, as the higher the voltage the efficiency is much better on smaller wire. I can run a 6270 watt array at 466.5 volts at 13.44 amps. This allows me to run 100meters on 10awg with only a 2% voltage drop. All this means is the higher your voltage is the lower your resistance(aka amps).
Agreed 👍 thanks for the feedback!
Ive done real world tests and concluded that yes distance plus amps affects gains from thicker wire. But you want to consider average amperage not optimal. First of all, you will only get 80% of rated in best case. Second, thicker wire makes less difference when you need most efficiency- when its shaded and output drops to 30%...so optimizing for sunniest hours may not get you much over the whole year. That money may be better spent increasing your panels for cloudy winter days. Consider that for most overall yield per dollar.
Yes. Our solar systems from 1 to 20 megawatts in MA only consider 7 months of optimum solar. The other 5 months of winter are a bonus. And our 10ga wires run hundreds of feet from 500volts in 2013 to the 1200 volt systems now in 2024. The important thing for homeowners is to not cheap out and be sure they're using PV wire...and of course having a licensed electrician install the system. In MA only licenses can even touch solar.
@@Icehso140 Wow! At 500 volts (and even better 1200) the calculation shifts dramatically. Your professionals know what they are doing to bring up the voltage from the panels.
People doing smaller systems should understand that three things affect the wire size calculation: the voltage (often 100 or less), the watts delivered (again, I think 80% rated or even lower to save $) and the distance. Again, I contend that you don't need to care so much about maximum efficiency on the best days of the year at noon. You need sufficient efficiency on the medium days that are more numerous in your area when the power produced will be good but less. Optimizing wire gauge for the the highest possible output that you only get when there's more sun than your system is designed for is not usually the best use of funds. Exceptions would be maybe running AC on the sunniest days or a grid-connected system that pays back. But good to recognize that seeing that 80% of panel rating may only happen for short periods and when you least need it. Might make more sense to spend that money on more panel for the shorter or cloudier days. Of course, it's an iterative process. More watts bigger wire...
@@ceeweedsl Thanks for the reply. I played with a battery backup/inverter setup for running my furnace for a few hours. Cost: one battery, 2500 watt pure sinewave inverter, battery switch...$700. Add 2 panels and charge controller...another $300. But I have nearly unlimited funds...as long as my wife doesn't see this. LOL But if someone can add a panel or two, it would be good, and Amazon has a pair of decent panels for less than $200. Buying used panels that are still good works to. Solar technology has increased efficiency times 3 over the last 10 years, and the panels we installed 10 years ago are still working within warranty. As they get switched out ,they become viable used panels for homeowner projects. (As long as a licensed electrician supervises the installation. )
Good info! Just to eliminate any doubt you should periodically series (butt to butt) test the accuracy of your meters. Probably no issues but you never know. Worked with this stuff for over 30 years. It happens.
Another way to calculate efficiency loss is the look up the resistance of your wire (and multiply by 2 for round trip resistance) or simply measure it with your ohm meter if you have one. Then, instead of the usual power calculation of volts times amps, you can also use resistance times amps squared. Use the amps number from the power monitor nearest to the panels and multiply by the resistance you measured (or obtained from Google). The lower currents that i observed in your measurements accounts for the lower than expected efficiency loss. If you repeated the test with the 2 panels wired in series, your efficiency losses would be half of what you measured for the parallel configuration. Because temperature voltage losses especially in the summer can have a confounding affect on power (and thus interfere with determining is the wire is the major culprit), you should use the Power = I (amps) X R^2 (ohms) equation when looking at wire losses. Conversely in the winter, the max voltage of the panel can be quite a bit higher than what the ratings are on the back of the panel, and thus also confound trying to see what the wire gauge affect is. Nice video! I also use 100 feet of 8 gauge when hooking up my portable panels.
That is a ridiculous pain in the butt. Just do it correctly and use a VDI chart that you can find on Google.
I think it's P = I`2 X R
That's great and all if you're retired and have all kinds of time on your hands. Or you could simply use a VDI chart and be done in about 30 seconds.
Thanks for the video. Very interesting test. Ive always wanted to see that in the real world. However I would definitely be going for the 12 awg, especially if the runs are small and they very well could be, with Panels located directly above your Solar chargers. I dithered for ages, 18 years ago when I first installed my off the grid house worrying about the gauge of wire. Turns out line loss is the absolute least of your worries and is easily fixed. A couple of extra panels will cover any line loss. Wiring 12 gauge and higher is significantly easier than any of the lower numbers for a DIY. Anyone fought with Crimp lugs on fine stranded 8 gauge wire 😞 Having said that though... Cabling between your Batteries and Inverter should be as big as you can possibly get. Double them up if possible. That's where you will get the best value in your cabling. Your Inverter will love you for it.
Are you meaning run two leads instead of one when you say double them up? Or double the gauges? Because the first one is something I’ve been saying (and of course have known) for a long time. When I ran my Romex 75 feet from the post inverter breaker box, I did just that. Two ten amp wires can carry 20 amps, and connecting them at either end is perfectly fine. Imagine the multi strands inside insulation. It is the same thing. And better for heat dissipation. Nice clear correct info, by the way.
Yes running 2 leads to give you a great big lead is a great way to solve lack of instantaneous power. I had a problem with a 5KW inverter that had the recommended size battery leads that kept going into fault mode with any sudden large motor load. I doubled the Cables and the problem went away. Very easy to do in an existing installation as well because you can keep your down time to a minimum, and 2 smaller cables are normally cheaper and can give a larger square area of cable. In this situation I was looking at installing soft starts on the motors but didn't need to. (Still keen to try them out though, so I may still do one anyway) 🙂@@5400bowen
@@garyrussell5559 I also heard that electricity runs on the outside of wires, hence multi strand wire (did I already mention that about multi strand?). Two smaller wires have more surface area for that to happen. It never occurred to me that a double lead was better for high surge devices, seems peculiar. But like my brother said, electricity is magic! And you of course saw what I said about running two strands of Romex because it was rated at 50 feet at my power levels and it is a 75 foot run? The rest of your reply is so pleasantly accurate! Aloha from the big island of Hawaii!!
Agreed. Real world amperage is usually much lower than rated. Especially Winter and cloudy days, morning and afternoon.
@@ceeweedsl Very true, and one of the most disappointing things you discover when completely Off Grid is that in Spring, summer and Autumn, your battery bank is normally fully charged before noon and the solar is pretty much dumped after that. In winter however I could triple the amount of solar panels and still struggle to charge my batteries on most days. My last array of solar panels I installed are completely for the winter sun and are almost upright. Panel angle lets you squeeze that last bit of current. I've found with Solar, when you miss, you tend to miss by a mile 🙂
Wow, nice job in explaining what this even means. This tells me that this industry is ALWAYS fighting physics. Wow!
It's quite a balancing act! The MPPT in the power bank will set the optimum VmP at the point of entry; the panels themselves will be at a lower VmP due to the voltage drop over the feed-wire system. This will mean that the panels will not be operating at their optimum MPP. Next, the power-bank will have a conversion efficiency curve for different DC input voltages; changing the input voltage due to the loss on the feed, will alter the efficiency, and how hot the MPPT gets. For my home DIY off-grid system I used short separate runs with the thickest wire I could afford, before the cost outweighed the benefit. From an engineer's point of view, efficiency is important; from the amateur's point of view, does it work?
The Delta Pro will only use 15 amps, which means that it current will be limited to that level throughout the circuit regardless of the voltage.
In another video he had 4 panels in series going to the battery, and it was over the rated input voltage for the battery unit, so it would not charge. The unit blocked it. He had to reduce it to 3 panels in series to get it to accept a charge.
A reply I did to another’s comment: A shed costs a lot more and is WAY more work than conduit and heavier gauge wire. Though a small enclosure for a combiner box at the panels is very practical, but the combiners are generally set up to be outdoors. So they don’t need a totally weather proof enclosure like an inverter and charge controller will. That makes a BIG difference in time money and effort. Plus, the batteries need excellent weather protection, and you don’t want your batteries a long distance from the inverter or your breaker box, or the end use point(s). So in my case I don’t put panels on my roof because that is a whole can of worms for installation and roof repairs/replacement short and long term. I have a nice exposed hill that I put my panels on and it is just simpler to run 4 AWG into a weather proof cement board cabinet close to the cabin with the controller/inverter/ batteries.
From Leo: Look up whatever wire size that the charts recommend. The ampacity charts have been standardized since WWII. Don't forget to de-rate according to length and temperature if applicable. Then use 1 size thicker. That is how I sized conductors in industrial applications since the 1970's. Everything I set up is still running even in horrible conditions. Whatever you think you are saving today will always bite you in the long run.
Thanks for the feedback 👍
You seem to be confused about ampacity vs voltage drop calculations. There are times when ampacity matters a lot, and so maybe that approach worked if you were pushing those limits more than voltage drop. An example would be short runs of high amperage, higher voltages. At that point voltage drop is out of the picture and ampacity is the limit. But for solar panel runs, not likely. An 8 ga will handle 40 amps and stay cool enough but that doesn't mean it's a good choice for 35 amps @ 12v over 300 feet. Nor is upsizing to 6ga adequate in that case. Use a Voltage drop calc and don't worry about ampacity in this usage.
I own a couple of meters similar to what you used. I've noticed what the meters show for the same source can vary a bit. This might contribute to at least some of the difference seen with the calculated values.
I think you are right. I am thinking about stepping up the testing equipment. Do you know of any higher quality power analyzers with a wide range of voltage and amperage capability?
@@everydaysolar For what I am doing, I couldn't justify more expensive meters, so I can't recommend anything. I did get some cheap "voltage reference" devices to test my meters, but they only go up to about 10 volts. Until you get better gear, you might try repeating the test with the meters swapped, then average the results.
@@everydaysolar Use A-B switching and operating conditions as stable as possible. Connect one device to the A side, note its results, swap to the B side, and note the results, swap back to the A side and note the results again, ensuring they read the same as before. If not, try again. Do this multiple times so you get at least three sets of good results at a given light level. Repeat at different light levels. Your records and a bit of work in Excel will allow you to cross-calibrate the two devices - "correct" the readings of the B device to match the A ( which you chose as the "standard").
Yes, when testing electrical values, it is best to repeat the test multiple times, pulling the test probes off and checking again. Rubbing them on the contacts as you watch the meter readings. A lot of electrical and electronics pros do it. False readings are quite common from faulty contact of the probes.
@@gregvanpaassenI’m sorry, what are the A and B sides?
Solar wire comes in two flavors. 4mm2 or 6mm2. Both are rated for 50amps and 1000v and are tinned copper to stop the black death. Most inverters are rated at 16amps and 500v. They would have to be in series at 9amps per panel. Just keep connecting your panels until you hit the max Voc of 450v. 9amps and 450Voc. 4000watts per string. Some Charge Controllers MPPT will have 150v but 50amp. These are ok for short wire runs on DIY systems. Renogy Rover type chargers for RV's.
Great testing! You did mention a series configuration but you never tested it. The thing about going in series, which I don't think you mentioned, is that you cut your losses to 1/4, not just 1/2.
So if you go back to that calculator and put in 12 AWG, 40V, 16A, 100ft, you get a loss of 15.8%. The equivalent series configuration would be 80V, 8A, and if you plug that in you get 1/4 of that: 3.95%. And that's with 12 gauge.
For a whole-home system it is far better. Now you are running 240VAC with micro-inverters, or in the 400VDC range with a string inverter. The percentage losses with 12 gauge wind up being 1.32% @ 8A and 240VAC, or 0.79% @ 8A and 400VDC.
This just goes to show, going for the highest possible supported voltage massively reduces wire losses.
That said, I use 10 AWG for all my panel-side cabling. Actually it is even a bit thicker since it is 6mm^2 cable and 10 AWG is 5.3mm^2. I'm just a bit of a perfectionist. I just like the feel of the cable.
Thanks for the feedback and I would like to test a higher voltage as I agree that is a more practical and smart solution. The little power analyzers are pretty limited in the amount of voltage they can handle so that was the limiting factor for this test. I am thinking about stepping up to some mid-grade testing equipment which would expand the capabilities.
(this phenomena is also why people are moving away from 12V battery packs and to 48V battery packs for new ground-up builds. Because the losses and heat in the compartment at 48V are just 1/16th losses and heat at 12V). Now that 48V LFP battery packs are so easy to find.)
I've used No. 10 wire casually between 100 watt panels. The sum runs into heavy aluminum outdoor wire. 21 volts runs through long wires into regulators, one per battery set delivering 12 - 13 volts into lead batteries. The solar wires are long and the battery wires are short. No problems with efficiency.
Does electricity run THROUGH the wire
or along the surface of the wire wire ?
@@andrew_koala2974 Through. The voltage loss between your solar panels and your charge controller means a lot less than between your controller and your battery.
@@andrew_koala2974 The phenomena of electricity takes place outside of the wire
You mentioned pros will be around 3-3.5% which sounds like a reference to NEC. Thats just a suggestion by NEC code. You should shoot for 1.2-1.5%. Can use 10 awg at close points to the array then in a combiner or JBox jump to an 8 or 6 for the long run to get to 1-1.5% drop. The lower the drop the healthier the system will operate ( most efficient)
The UnboundSolar calculator seems to be set up for AC current. AC current flows more towards the outside of the wire (skin effect) and doesn't make full use of the core of the conductor. DC current uses more of the copper in the wire and therefore has less loss. I think this effect could be contributing to the differences you see in your tests and what the calculator results show. I.e. the calculator will always overstate losses if you are using it for DC currents.
this is true. its a fulty test
This is a common myth. Skin effect only starts being a thing at radio frequencies from around a few MHz and up.
At 60 Hz it varies between zero and virtually indistinguishable from zero, so the full cross-section of the conductor is in play.
V = I x R. Higher the resistance, the higher the voltage drop across the cable. Since Power = V x I, as voltage goes down so does power at the power station.
Yet another way to look at this is Power = V^2 / R. Even though R goes down with lower gauge wire runs, the reduced voltage (due to above) reduces by the square and the power delivery to your power station is lower.
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100 feet is a long run. If you are building a system that uses more than just 1 40V panel, you can place the panels in series to increase the dc voltage, this will improve efficiency, but on the down side high DC voltage is a acing fire hazard. This is how the pros do it have hundreds of volts or the max the MPPT can take. If you what to be safe use 35mm2 or 50mm2 or 0 awg aluminum xlpe as the main trunk this will keep voltage drop down in a extra low voltage system, and aluminum cable is cheap. Be careful with you're terminations on aluminum thou.
Need to do this type of testing on a perfectly clear day. Additionally, always wire up your series/parallel solar system to give you the highest voltage acceptable for your inverter to get the lowest losses.
Why didn't you use the 4.53A in your calculator that your meter was showing? What I do is have a battery at solar panels with an inverter hooked up to it then use a normal 14ga outdoor extension cord to run power inside to charge house batteries.
Good to have some empirical data as well. I would suggest however that you do each of the tests twice and swap locations of the EcoFlow meters just to eliminate calibration differences in them.
Not a bad idea, thanks for the feedback.
It would be interesting to see how accurate the meters are.
I was going to comment a similar idea, I have found I would rather like an existing comment then to duplicate a comment.
I wind up duplicating a lot because I haven’t read all the comments and replies yet. This video and comments are a cut above.
good show, but would have been good to let folks know that increasing panel voltage is a great way to reduce line losses (and therefore downsizing gauge of wire). This is the case since line losses are proportional to the SQUARE of current but only directly proportional to panel voltage.
Yeah, that would have been a good addition. I was keeping the voltage low for the power analyzer limitations so it was a bit misleading as compared to what you would setup in most real work applications.
What is actually been drawn heavily affects what the panels produce... You plugged into a battery... So it's state of charge will change production.... Should hook them up to a heating element through the mop, that will put a constant pull... And you will also see how hot the wires get as well when under heavy load.
I get that some of the calculators need help in their calculations, but the most important thing in sizing that you need to really worry about is the length of run, not the actual loss. A run of the wrong size for your configuration can/will result in a fire and that will be more of a worry than percentage of loss from wire size.
VDI chart works great. I always run my large ground mounted solar array wire runs in DC, and I keep my operating voltage up around 500 V DC.
Yeah, if you can crank up the voltage and keep current as low as possible that is ideal 👍
This is also why you should go as high voltage for the long cables as possible.
I have a "off grid" 12v mppt inverter that accepts 56v input and i have open circuit voltage about 54v so there is little loss before the inverter.
Also my "on grid" inverter have 470v input
Always have as many panels in series as the inverter accepts (open circuit voltage, no load!)
higher voltage less loss. also keeping your wires as short as possible also helps.
I wrap all of my outlets in good tape. I'm a property manager and you wouldn't believe how many people remove outlet covers to put fancy ones on and then tell me how they go 'shocked'. Once a year at least. That may not sound like a lot but we also have a stainless steel back splash in the kitchens and that doesn't help. People will remove them when they move and put the cheap plastic ones back on...
I will always wrap them. Not for my safety but for the non-electrical person who wants to open them up and change covers... I'll never get shocked because I shut the breakers off.
Don’t worry about the 15 amp limitation.
Amps are "pulled" by the DP so there is no concern with being over 15.9 amps.
The “maximum” of 15 amps is a limitation of what the Delta Pro can consume or take in itself.
So even if the panels produce 20 or 25 amps, the Delta Pro will only take 15.9 amps.
Think of the 15 amp outlets you have in your house. The breaker in your panel is rated at max of 15 amps but when you plug in a 100 watt light bulb into the outlet, the bulb doesn't pull 15 amps. The bulb only pulls the current it needs to operate the bulb which is what the DP does with the solar array power.
However, volts are "pushed" so it is CRITICAL that the 150 volt limit of the DP is NOT exceeded under ANY circumstances after factoring in lowest panel operating temperatures.
Most DP users look for panels with a VOC around 40 volts and connect them 3S or 3S2P or 3S3P or even 3S4P to be over panelled for less sunny conditions.
Each of my arrays have a total of 3,240 watts but the DP caps the input at about 1,605 watts but it allows me to retrieve the full 1,600 watts for maximum amount of hours throughout the day.
Another option is to use micro inverters and convert to AC at the panels so you can use smaller wiring. The tradeoff is conversion loss so you need to determine which is worse, the line loss or the conversion loss.
The measured results don't match the calculator because the maximum amperage was used. Voltage drop increases as the load increases so, as has been mentioned, keep volts as high as your equipment can stand to minimize amps and voltage drop.
7:36 Your calculated loss (Column E) is percent "voltage" loss while your "watt-hour" loss (column D) is percent "energy" loss. You need to adjust one or the other to be identical units before directly comparing one with the other.
The calculators also are based on "temperature range". You are at an "ideal" temp. If you did the same test on a much hotter day you'd have much higher losses.
One other issue to consider on the wire sizes is that when a wire is run over a roof, the wire can retain heat from the roof and you loose some power there too. 10 awg would be minimum for me on a roof to compensate for the additional loss.
And that heat cooks your wire. Even the metal is more quickly degraded from heat, and especially the insulation. Wire for outdoor use should be white.
run it through the attic. Yes, there's still some heat but not as much.
@@georgeperez4770 a valid thought. Or use white wire, or run it straight down as much as possible, or as I do with the cabins we build in Hawaii, use white roofing. But just look up videos on insurance and roofing companies reaction to roof mounted panels. When the roof needs replacing, yer gonna bleed hard. Some insurance companies have started refusing to insure homes with roof mounted panels…
With an eco flow delta pro, the max amperage you can get is 13A. The MPPT is not capable of taking any more.
Further: Putting the Panels in Series (2x the voltage, 1/2 the current) will reduce the loss to 1/4 (3%for 12 AWG and 1.5% for 10AWG).
Plus:
The max Power you can get with 2x360W panels in parallel is 40,95Vx13A=532,35W
The max Power you can get with 2x360W panels in series is 81,9x8,79A=720W
Delta Pro is 15 amps.
@@jacobpetersen5662 Thanks for the correction. The user manual I had when I wrote that comment, specified 13A, the current one specifies 15A. However, it does only slightly change the calculation (613,25W va. 532,35).
Better to put panels in series to provide higher voltages. Power loss = I^2*R. double the current and your losses increase by 4.
Yup, most people forget the square.
Perhaps the device he is charging cannot handle the higher voltage.
The current flow is what is charging the batteries. parallel panels allow for more current and faster charging times. The solar charge controller regulates the amount of current delivered to the battery it recharges. I
@@zaneenaz4962 Battery charges have a current regulator (something like a constant current regulator) Batteries are never charged directly using the PV voltage as it too high. the Battery charger will step down the voltage and supply higher current for the batteries. Basically it will use a Buck step-down converter will will drop the voltage and supply more amps than the PV panels can provide.
@@zaneenaz4962 Not really true.
With an MPPT, what matters is POWER. The MPPT is a buck converter which will convert that power into current.
If you have 2 panels of 10A each and 25V they can be wired in series as 50 V at 10A or in parallel as 25V and 20A. The POWER is the same either way: 500W. The MPPT will convert them both into the same number of Amps at whatever the battery voltage is (ignoring slight differences in efficiency at different voltages). Ignoring losses, that would be about 41A at 12V.
@@cccmmm1234 The power transfer is noted, but would you not also be increasing the resistance when the panels are in series? ....and the buck converter efficiencies are typically below 90% (another source of loss) As the systems scale up i suppose these loses drop off as lower percentage of the overall system. Leaves me to wonder if my 300W systems might not behave like your 500W.
I think some people might get the wrong idea. From the comments people are assuming that the fatter the cable the better. Which the answer is still yes but what if you have a small set up? If you have a smaller setup that has a lower power output with wires that don’t need to reach 50feet or 100feet getting a bigger wire can also cause power loss too? I’m talking about 13 amps 36 volts at a distance of 10 feet or so.
Or am I wrong?
Voltage drop = (2k x l x i)/Cm k= 12.9 for copper wire, l= 1 way length, i= current, Cm= area of conductor in circular mills
That was just for 12v. Now in a 24 or esp a 48v system. The wire gauge isnt near as much of a Factor. Great video thx
If you could datalog the voltage and amps through the testing period you'd be able to see why there is a difference between the online calculator and your measurements. What you want is the average value of the amps squared (amps * amps at each point) over the time interval. Take the square root of that [average current squared] number to get an "average" current value - and feed that back that into the online calculator. It will show a result that is a lot closer to your measurements. The growing difference in the loss % with each larger gauge wire is explained by the lower total Wh over each test interval. You would see the opposite trend in the closeness of the % loss number if you had a higher load for the 8AWG vs the 12AWG tests. Some rough calculations assuming a 40.5V constant system voltage (needs correction: all of your photos show actual voltage ~36-39V) show that if your trials were approximately 90 minutes for the 12AWG, 75 minutes for the 10AWG, and 80 minutes for the 8AWG - then the theoretical numbers from the online calculator match up. I think if you were able to fully load this system - receiving a constant 17.8A at 40.5V (721W) - the online calculator would be spot on versus your measurements.
When going for larger wire sizes (I will use 4 gauge) take care to avoid wire that is stamped 'CCA'. This is an acronym for Copper Clad Aluminum. You would have to upsize a wire gauge to get similar results. The number would get smaller - 2 gauge CCA instead of 4 ga. copper.
The amount of power running through a 4 ga CCA wire that we are referencing here... there is going to be negligible difference CCA vs OFC. Now if your running a 5000 watt stereo amplifer pulling current directly from the battery, then yeh OFC is a must have.
@@KingMrBigE nope - 500 watts of panels can be around 30 amps. Use the calculator and see for yourself.
If you can tolerate more than 10% voltage drop, than I don't care either.
Your charge controller adapts to the lower voltage, an amplifier can't.
I just don't want to waste the precious power if I can avoid it.
If you simply default to a huge wire like that you are considered an electrical hack! Do what is correct and don't default to big wire as that is pure sloppy workmanship.
@@boblatkey7160 whoa. back off. I didn't default to anything. (5) 100 watt panels, 6 amps each, 12v, 30amps system. 20 feet of 4 gauge wire - you run that through the calculator.
I prefer 3% voltage loss or less. THAT is good design.
@@jamesalles139 the difference between a CCA vs a OFC 4ga cable is not 10%...
Great video thanks so am I right in saying just use the thickest wire you can get?
Maybe go to AWG 6 for achieve a lower loss than AWG 8 or are there other factors to consider and it’s not as simple as just the thicker the better?
Also Rather than running separate wires is it just the same to run a 2 cable with both the wires in that cable.
Thanks to anyone who can answer this in advance.
Here is my Theory, you did your Tests and its a great Explanation which made me think more about the "Wattage Loss" going into the Charge Controller, your "12AWG" wiring you lost 90.4 watts just from wire length and 32.7 watts from 10AWG, what if you reversed the setup, going from the Array with say under 10ft directly to charge controller, then have Inverter power line to be the 100' length pulling from stored capacity over to the home/off-grid cabin, then voltage drop or "Wattage Loss" would be reduced dramatically giving you better charging capabilities utilizing the most out of your solar panels.
My Theory is if the Stored Energy in the batteries has voltage drop from the inverter wires to the house VS Array wires to Charge Controller/Batteries in the home, its just less power being taken from Stored Capacity and Technically the AH Stored is never lost from "Voltage Drop/Wattage-Loss" like it would be Entirely lost from the Array wires to Charge Controller.
Let me know what you think, or possibly another Test lol
That's great but didn't mean anything to me. What are the metric cable sizes? 4, 6, 8mm2?
Interesting topic. By making measurements at the start of your cables and at the end of your cable you can narrow down to line losses, but you still need to consider the varying current flows. The 12awg starts with 12.9A and ends with 16.3A (why the wide range?).....the 10AWG starts with 4.7A and ends with 4.6A (more reasonable behavior). The greater the currents the greater the ohmic losses ! Line losses are lower with the lower currents.
Having worked with different batteries i've noticed they draw power from the PV-panels differently, so the state of charge of your batteries should be considered.....they should be similar across both tests. The lower the state of charge the higher the current flow when using a PWM-type solar charge controller. Have not had an MPPT unit long enough to test this, but i still can imagine similar behavior. My inverter experiences make AWG and wire type a high priority ----> ua-cam.com/video/xK0L4dOMpSc/v-deo.html
Yeah, not a bad call out as a I think the 10 AWG test had a little more cloud cover and as such dropped the current resulting in a little less line loss than if the test had full sun. Overall I think the results are still valid within a reasonable error band.
And because the conditions differed, it invalidated the test. Current should have been equal and at the maximum design level to get accurate loss results. Cables will also have to be derated depending on how many cables are in the conduit and outside temperatures encountered, as all loss turns to heat and adds up, creating a safety issue if not considered. Is the conduit in direct sunlight, that's another thing to consider. Check the temperature rating of the cables as that needs to be considered also. Yes, there is a lot to consider for the DIY installer. @@everydaysolar
I measured my hundred foot run with 10 gauge wire and it came out to 0.61% Percentage of Voltage Drop with the calculator you're using... Not too bad
A small point. I noted the calculator you were using started 1 phase, that I would assume relates to AC current. My understanding is that losses are greater in AC circuits than the DC that the panels provide
With AC, you need to consider reactive circuits . The phase of current and voltage shift.
@@chuckmaddison2924and the skin effect.
AC current moved in less area of the wire. DC current moves in the whole area of the cable.
@ajarivas72 Skin is related to frequency. This is why in rf pipe can be used in the big stuff.
That is 100% untrue. The voltage drop is the same whether it is DC or AC. End of subject!
Wattage and Amperage:
* 100W: 16-14 AWG
* 200W: 14-12 AWG
* 300W: 12-10 AWG
* 400W: 10-8 AWG
Distance from Panels:
* Short distances: 10-12 AWG
* Longer distances: 8-6 AWG
Voltage Drop:
There's a reason that high-tension power lines run much higher voltages than house current. And a somewhat related reason that AC dominates over DC, although DC can definitely be transmitted. If I was doing my house to replace grid power, I'd be looking at the storage devices available and trying to match the panels and the wiring to them for best effect, reliability, and longevity. And the copper wire probably (expensive as it is) would be a comparatively minor component of the cost. I'd likely favor the largest gauge practical, because the expense is one-time. Also, panels are necessarily outdoor, and need appropriate provision for electrical storms, which (I imagine) might be a relevant factor. Surely I'd want the advice of a competent engineer, either independently or with a trusted vendor; too many places to make mistrakes.
Number one problem that I see with this test is the wires appear to be exposed to the sun's heat. The heat from the sun will increase the resistance of the wires---making the voltage drop percentages higher. It is more likely that, especially for residential, the wires would be at least in conduit and most likely buried in the ground for most of the run. So, the drops would probably be less. However, the delta between the gauges would probably be in the same range as tested.
You should use standard wire cross sectional area of mm2. The Dawg you use is obsolete, especially having smaller numbers mean larger cable.
For a real world setup with the panels 100 ft. from the inverter, I imagine that the wires would almost certainly be in conduit underground, which would be a whole lot cooler than sitting on concrete in direct sunlight. I think that your test conditions probably made it appear that you needed a whole wire size larger than you would if the test were run underground in conduit.
For 100 feet even with this small two panel setup in parallel, I would go 4 or 6 gauge. Sure, costs a lot, but you pay for wire once, and it degrades over longer periods of time. But the losses are continuously reducing your power production, every minute of every day for years and years. Then there is durability and ability to add on. Add it all up.
So the best thing to do would be to Install an all weather Inverter like an SMA Sunny Boy close to the panels and A.C. to make the long runs to the point the power is needed. You have a lot less loss with AC vs. DC.
Yeah, not a bad plan 👍
Should have put the 100 feet in the shade; hirer wires are also an efficiency loss.
You mentioned the series connection, but didn’t test it.
The higher voltage will be heaps more efficient and cheaper as you can use thinner wire.
I’ll look for a series panel video now; I hope you did it already.
Upping the gauge of the cable increases the cable cost fast. It might be cheaper to run two separate cables, one for each panel of lighter gauges and combine them at the receiving end than to run one heavier one.
And also, silicon & glass is cheaper than copper. If you have the space it might be feasible to install an extra panel to make up for the voltage drop rather than spending that (or more) money on a bigger cable. This also has an advantage of keeping the output higher under less favourable light conditions, where the current is lower anyway therefore the voltage drop is less of a factor.
Of course if you can run the panels in series (if you have MPPT with an adequate maximum input voltage) then you massively reduce your losses. However, parallel has one significant advantage. In series, shade one panel and you wipe out the production of both. With a parallel setup one panel doesn't affect the output of the other. They can even be pointed in different directions to passively :"track" the Sun over the day. In series they must receive the exact same insolation.
If you were charging a battery there is absolutely no benefit from facing some panels in different directions. What you want is the maximum amount of amp hours delivered to the battery and that will only cut into that.
Yep. Plus, easier to work with.
@@boblatkey7160 If that's *all* you are doing then that is probably the best way to go. However, if you are charging batteries and running loads all day and night, such as in an off grid household then things become quite different. Having some west facing panels makes a massive improvement to battery life because it lengthens the time each day the loads are purely solar powered, before dipping into the stored charge in the battery. It all depends on how large the solar array is and how big the battery is. 2 x 100 watts into a 100AH battery, for example, you probably want to point 'em the same direction.
The calculated losses are probably higher because they take into consideration temperature change of conductors exposed to heat accumulation either by heat generated by current or from heat from weather and the sun and enclosed conductors in conduit or hot attics. heat increases resistance and would increase amps.
I've heard that AC has less lose over longer distances than DC. With that in mind, would micro inverters be a good idea for solar panels that are far from the house?
Low current / high voltage will always be more efficient from a line loss perspective. This is why electrical utilities use high-voltage lines. P = V x I^2, so that current is exponentially more influential on the power loss of the system. The best scenario is to connect the panels in series if the design can handle it of course.
Of course, but this is surprisingly low current for the wire gauge! My larger array has 2 strings, 7x 72 cell panels in each one, a little under 400V on the string, but still has decent amperage in what I'm guessing is 8 gauge but can't remember anymore. 7.5amps per string likely by my calculation but I guess that's peak sun, so the top 1-2 hours of the day and the rest it's below that. Maybe not too bad afterall, but man, upping the copper thickness would likely pay for itself, everything else staying constant!
Have you ever heard of the Shoals Plug and Play cables/system? Can anyone judge whether it makes sense to use it? Although they seem to be a bit more expensive, they are extremely easy to use and no professional installer is required. Installation is also said to be very quick and more energy efficient than conventional cables. What do you think about that?
They have cool products but I have seen their use case more in the large solar farm application where you can get rid of combiner boxes with 1 massive wire that has a bunch of leads coming off to each string of panels. Which of their products were you considering?
The conclusion of the video is that for DIY solar projects, using 8 gauge wire significantly reduces line losses compared to 12 gauge and 10 gauge wires, with a loss of only 3.3% compared to the expected 6.9%. The video emphasizes the importance of choosing the correct wire gauge to minimize voltage drop and improve overall efficiency. It also suggests considering series and parallel configurations to optimize voltage and current for your specific setup. For larger projects, such as grid-tied systems, professional installation is recommended.
I keep mine under 2%. The tables are based on a temperature coefficient, high temperatures create more resistance, therefore more voltage will drop more. When the voltage drops the wire heats up giving you more resistance. Hence the voltage drops even further.
Over time this can be a problem.
Silly test, because line loss per foot and current is all known and in online tables. They are very easy to use, so you can find out what your system line loss will be for each gauge wire. These test high line loses are because there is very high current flowing through the wire. In a real DC system, you want series wiring so you have as high a voltage as your inverter can handle. The current would be about 8 to 9 amps (whatever a single panel puts out). That will minimize your line loss.
My 5 KW array uses two series strings, with 12 panels per string. Each string feeds it's own MPP inverter channel. That's about 430 volts at 8 amps, well within my grid-tie inverter specs. My line loss is minimal with 10 gauge wire.
I spotted a potential flaw in the testing. The Yunsailing 100V watt meter uses 12AWG wires. So it would automatically add 12AWG loss wherever you add it in the chain. I imagine for more accurate results you would need to resolder 8AWG wires to the Yunsailing, or get a higher quality meter such as the Powerwerx Watt Meter Plus, which uses 8 gauge wires with preinstalled SB50 Powerpole connectors.
Isn't the distance of those connections so short that the effect would be trivial? You also have to go with the AWG of the connections to the panel itself.
Good info. A dc power supply may be thought to use for a consistent supply voltage and current availability for future tests.
Yeah, that would help compare apples to apples. Thanks for the feedback!
Would have been nice to see loss in series under 50 feet of wire which most people use! But, this was very informative! Thanks
And now how much do you loose by not keeping your panels pointed into the sun? I think you can point the panels and get more than the wire losses. And by the way, it really dose not matter if the battery's are charged by 10 AM and you are not using much power during the day.
Great video, but I was wondering about the grounding wire from the solar panel frames to your main house grounding rod. What gauge should that be?? Thank you.
I use 4mm², that is AWG 11. The new cables I have now bought are 6mm², AWG9½ - copper
100 feet are 30m. I don't have the cables for that long.
Do you think that measuring device introduces some loss too?
Sure, some. But any loss is consistent with each wire gauge tested so although the percentage losses shown might be slightly affected the overall message is the same. 8 is better than 10 is better than 12.
I think you should repeat the test with a constant DC input power supply, instead of a solar panel. Always control for as many variables as you can, to get the most scientifically reliable and repeatable result.
No. This is not a test of wire performance - thats already been done. It is a test with real world factors in the mix. Thats the next step for more nuanced understanding and decisions.
Thank you for running your real life experiment. I noticed that your running stranded cable. How would it compare to solid core wire?
I'm more interested in wire sizes on batteries. I believe you need bigger wire on a 12v system, and a little smaller on 48v. I'd like to know what size to use on a 48v battery
Did you use a solar-to-xt60 Y adapter to connect the 8AWG wire to the EcoFlow? If so, does the adapter need to be the same gauge? I can't find an 8AWG Y adapter anywhere because the wire is so large. Is it OK to use a short 10AWG Y adapter with a long run of 8AWG wire? THX
Question: Have Rich solar panels with 12 AWG MC4 connectors. Thinking about using 8 AWG wires to a RV charge system. System will have 10 panels at 2x 100 watts connected in series / parallel, Panels @ 20V / 5A each= 40V / 25A total. Need information concerning connecting the 12 AWG MC4 to a 8 AWG MC4 or is that even a thing?
082723/2041h PST 🇺🇸. Thank you for the presentation on simple and adequate PV cells setup. Yes, it’s so true to venture out to connecting to 110AC system and automatic changeover switching, which is all too much for layman and myself ( electrical engineer)
I have a similar set up 800W PV array and 2X12.80V@540Ahr LiFePo4 Battery, and 1200W inverter. All equipments are VICTRON. Here, in CA , we don’t experience load shedding or Blackouts. But it’s better to possess such a system, than not.
I’ve watched your electrical systems wiring etc, a lot. Thanks again. Best wishes.
this was really good. seeing real world results are better than calculating estimates! 🙂
Great video and very informative. But there was one piece missing for me. If I go with the 8 gauge cable (my length is going to be about 100' to my ecoflow also), what about the XT60 connector from the 8 AWG (MC4 connector) to my XT60 connector, which only come in 10 gauge options. I cannot find an 8AWG MC4 to XT60 connector for my Ecoflow. Will having a 10 gauge 2' connection cable defeat my long 100' run of 8AWG wire?
Just came to mind I have 10 gauge, but at the connections, the wires are very, very small/thin gage , so does that reduce the 10 gauge down to these small wires?
That should not be a line loss issue since it is reduced for such a short length but you would want to make sure that thinner gauge can handle the current load from a failure/heat generation standpoint as opposed to an efficiency/line loss perspective.
Amps and volts determine what size wire the wire also has a factor on that too
Thank you for this video!
A question, the analyzer you are using, I was wondering if it has the ability to record data points over an extended period of time? If it doesn't do you know of a similar solution for a similar price that does do that?
Thank you!
This one will just continually record the active session (session starts when you plug it in) but is limited outside of this basic functionality. I think you could pull this data from the device through the serial port into a Raspberry Pi or similar device to provide much more functionality like plotting out the metrics over time.