Folks there are some very good charge controllers out there But I recently purchased a VICTRON CHARGE CONTROLLER 100-30 There are no words to explain this product but I can tell you in my words that the quality & the workmanship of this product is second to none. I am so taken back on how beautifully this equipment performs. The reviews of this product is right on and I highly recommend on a scale 1 to 10 9-1/2 seven STAR
Don't freak out but it's 2am and I would hug you!!!! This video was perfect! I spent hours with videos that were 15 minutes long but the information could have been said in 1 minute AND they were a tad rubbish and confusing. This video was at the perfect pace and order to furnish organized information and the formula was like a Father's Day present to me! Thanks! Specifically because I bought a camper and it had a factory installed solar panel, the additional "plug" on the frame reads "Zamp", so I bought another Zamp panel, the exact one you showed. I did not check he operating roof one which I later learned was a 200W/43.83V/4.54A Sonali Solar! I was worried that they were different but then realized I could wire them in series to add the Zamp 18V voltage but since my Victron MPPT is 75V/15A. I was worried on exceeding the Amperage...but I read in comments that as long as the voltage stays under the 75V (my panel series add up to 62V) then the controller will limit the excess (could go to 24A as it trims the voltage to 14V) to 15 amps on peak sun hours. In other words, it would choke if too much voltage is fed to it but it can shave off any amps over 15. Hence, I thought about the 100V 20A to take advantage of the 24A potential, but I was worried the wires to the battery may overheat since they are concealed in the wall and I cannot figure out their gauge. I know that electrical Romex, even the 15A white one can handle 20A, just like outlets and switches, but I am not sure if the wires the factory used allow a tad more occasional juice. The tip looks like an 8AWG but it could be a 10AWG. Anyhow!!!! THANK YOU!!!! WELL DONE!!! you are a hidden treasure in the UA-cam jungle!
Now that I’m in my office, I have a longer response. If you put a Zamp panel in series with the Sonali panel, you will have a functional system that won’t fry your charge controller. You get a slight mismatch in current (4.54A vs. 5.00A) that will reduce efficiency slightly, but you’ll still have much more output than you would get with either panel by itself. As for wire sizes, the input to the controller can be small. 10ga would be fine. Output would ideally be 10ga. If you are interested, have a much more comprehensive explanation of solar system design here: amsolar.com/solar-charger-design
@@GarretTowneAMS You are the Man! it is working like a charm, and I am extremely proud (perhaps OCD) that the panel is perfectly aligned, that the cables re tidy and even the sealant is well shaped, ha! but most important is that the system is working like a charm and I see how it limits to 15A in the output, so I guess a new MPPT 100/20 should be beneficial. I truly thank you for the assistance and when the time comes I will buy the rest of the equipment and upgrades (if you ship to Fairlawn, Ohio which I am sure you do). I tried to upload pictures but as you already know I am technically challenged, LOL
Woow 🤩 after having made a million hours of research in about solar systems and stuff, that video is by far the most simple explicit professional technical way of explaining how charge controllers works!!! Thank you from France Garrett ;)
Thanks for the math lesson. That's exactly what I've been looking for. I just bought a 100/50 charge controller. So 4 100 watt panels should safely do it.
Thank you. I'm working on a new video covering this topic with more details. If you're curious, I have it written out here: amsolar.com/solar-charger-design
Hi from Aussie.. Really Great info A huge help.. Easy to listen to well done... and a big thanks for ( NOT PLAYING USELESS LOUD MUSIC IN THE BACK GROUND ) 5....Stars Liked and Subscribed
This is Awesome! No one speaks about input and output current relative to the amp ratings on these controllers. I also assumed series wiring would allow room for a larger array on a smaller controller. Wx90%/v=A. Love it! Thank you, very informative.
You can wire panels in series, but you must use a MPPT controller, not a cheaper PWM controller. Be sure to stay below the total voltage of your mppt charge controller though. If you are going to wire in series, you need to understand the math involved in electricity so that you keep you equipment and yourself safe.
Thank you for going over that formula, I almost under spec'd (3x) 180 watt / 9 amp panels as only being 27 amps, not 40.5 amps. That would have been a big mistake.
Just regards the rated output current , I've got a 100/20 Victron , its set to charge 12v batteries but it can charge 24v batteries too. As far as I know it can charge to that max 20 amp output current regardless if set to 12v or 24v batteries, so meaning you can put in roughly double the power / wattage into a 24v battery system compared to a 12v system.using the same MPPT controller , providing the solar panels are up to it.
You should mention that at 4:00, the v in your calculation is based on the current voltage of the battery at that moment in time, not some generic '12 volt bank" as you describe it. It's a critical distinction.
I know where you are coming from on this, and I agree that it would tighten up one aspect of the formula, but 90% is probably even more inaccurate, since it is supposed to encompass the wide range of sunlight conditions. I just use it as a rough rule of thumb and frequently oversize solar arrays (which is what would happen if you raised 12V to 14.4V). You can look at charge controller selection in two ways 1) Design it super conservatively in a way that no clipping is allow (maybe end up spending a little more than you needed to on the controller) or, 2) Ball park it, maybe oversize your array, and experience some clipping on bright days. On most of the charge controllers we use, an oversized array isn’t going to harm the controller, it will just limit the charging current on very bright days. Thank you for noticing that.
A 12 volt bank at 12 volt is what we see as empty, Charging to bulk mode is 14,4 volts , so using a mppt gives you even more amp input at low battery, just when you need it, And the percentage will drop down a bit by higher battery voltages, when the battery is gettig fully charged, Messuring from the over voltage you have present in the array, it wil work even better at lower battery voltage, producing more charge amps. (only iff you use the mppt controller) (its not the case in pwm controllers)
@@MrBugsier5 You are correct, but the point is that this is just a quick rule of thumb calculation. I could just as easily use 14.4V and 75% and come up with the same values. Variations in solar irradiance introduce more inaccuracy to the calculations than not getting the exact charging voltage and efficiency factor.
This is a very good description of charge controllers. However, your wattage calculations are all based on having a 12V battery system. If you have 24 volt batteries, the wattages double, and with 48 volt batteries, they double again. For instance, your 30 amp (maximum output current) Victron charge controller with a 12 V battery will output at most 360 watts, give or take a bit based on the actual operating voltage of the battery. 400 watts or so of solar panels would be appropriate. With a 24 volt battery system, that same 30 Amps will give 720 watts, and with a 48 volt battery system, that 30 amp output will give 1440 watts, so total solar panel output power can be increased accordingly. The charge controller will charge any of these systems because the 30 amp maximum current applies to all of the battery voltages. The Victron charge controller is even smart enough to auto detect the battery system voltage! This is an important point that wasn't covered in this video.
It’s been a long time since I posted this video and in that time we have done a lot more 24V systems. You are absolutely right. Don’t use “12” in all the calculations. If you have a 24V or 48V battery bank, use “24” or “48”. A controller will support twice the solar wattage at 24V than it will at 12V. When I get a chance, I plan on making a revised video where I also bring up input current limits, another issue missed on this video.
I love this informative video and I admit i'm a newbie at solar systems, but other videos / tutorials ive seen show that you can get closer to 1400 watts or more running on a 150v /60 amp charge controller as long as you're running a 24 volt solar panels / 24v battery, etc ? I realize that you said that the calculations arent black and white, but i'm confused because of the big gap between less than a thousand and 1400+ . I bet i'm missing something really obvious.
Thanks for a clear, simple video. Finally, someone prepared to de-mystify some of the "shrouded-in-secrecy" off-grid setup information. Frustratingly, the only information available on internet forums seems to be pitched at mountain-top level for advanced users only. Do you happen to know which Victron models have the bluetooth function? Mine is the Easy Solar 170/50 MPPT, and when I tried to scan it with the bluetooth turned on and using the Victron Connect app, I get "no device found".
If the Victron controller has "Smart" in the name, it has built-in Bluetooth. Otherwise, check out the Victron Bluetooth dongle that can plug into a VE.Direct port.
What we really need: A useful charge controller comparison. Measure the output of the not yet connected panel, the voltage at the input with the panel connected, and the voltage to the battery and load from the controller. Every eBay Price lowest first controller I have tested knocks the panel down to 11.8 at the input and sends that to the battery. No amount of control changing will bring that up.
Thanks for the input. What are some controllers you would like to see compared? This channel is an offshoot of a business that warranties work for the life of the install and provides high level tech support to customers that have issues. Because of that, we have to be very careful about the products we carry, and we feel Victron does the best job of keeping our non-revenue producing support (tech and warranty) to a minimum. So, we don’t typically have a variety of controllers around. The output of a panel that isn’t connected to anything would be zero. The potential output would vary based on irradiance, temperature, and the resistance of whatever the panel is connected to (i.e. the voltage at which current is being drawn). As for the rest of your comment, it sounds like you are dealing with a PWM charge controller. PWM stands for Pulse Width Modulation, and PWM controllers connect the panel directly to the battery. The connection is pulsed, with on/off cycles based on the voltage of the battery (roughly the charge status). If you are getting 11.8V on the panel side, that’s because your battery is roughly 11.8V, and the battery forces the panel to operate at that voltage with a PWM controller. There is nothing wrong with this. It works, but it isn’t as efficient as an MPPT charge controller that lets the panel operate at a more efficient voltage (usually 18V depending on the panel) and transforms that higher voltage down to something that is safe for your battery.
This was very helpful especially the bit about too much solar. Does the array wattage equation apply to pwm? If i use 160W panel, the equation says 12A. But the short circuit voltage is only 8.7A. What I really want is to get as close as possible to 10A for my battery.
Thank u very much 4 ur response.Kind of u. I have a 5 panels of 100 watts each.charge controller seems 2 b local made provided by solar installer.it is 12v/50amps. Don't know y it heats up
If they are all connected in parallel and you are using at least 6ga wire, you shouldn't have any issues. I would feel comfortable using a 30A controller on that. Maybe you got a defective charge controller.
If you use 520W for 5h per day, that works out to 2600Wh/day. For easy math, we tell people that 1W of solar will give them about 3Wh per day in decent sun. Obviously this can vary depending on a number of variables, but you would be looking at about 900W of solar. I might start with 5x 200W panels on an 85A charge controller. If you need more solar, you’ll have room on the controller for a 6th panel. I would use at least 300Ah of lithium or 600Ah of AGM batteries for this.
Great video, please make more. Quick question, some of the inverters have built in charge controllers , would your formula still work in that scenario ?
We haven’t worked with an inverter that has a built-in solar charge controller before, but I have heard of them. Make sure you actually have a SOLAR charge controller, not just a charger. If that is what you have, the formula would still work. I have several video scripts in the work, just not enough free time. We are insanely busy. Thank you.
Nice and very informative video , I didn't know that the Victron MPPT's just limit the current if there is over current ( I thought the fuse would blow ) . Thats very handy to know. Do they do the same with Over voltage? Say two 38V panels in series on a MPPT 70/15 Victron? thnx . What I miss in your video is that a good way to expand your system with the same charge controller is increasing the Voltage from the battery pack. ( say 2 or more 12 volt batteries in series in stead of just one 12V, doubles the amount of watt going in, but the amps stay the same ) and besides that everything becomes more efficient with a higher battery voltage. Thnx
Unfortunately, over voltage will damage the charge controller and I believe it damages it in a way that is very obvious to the warranty department, letting them know you did not follow the rules. It is true that you can double the amount of solar on an array by doubling the battery bank voltage, but that makes alternator charging very difficult, you would have to get a new inverter and DC/DC converters for your DC loads. We have a lot of people come to us wanting 24V systems and all but two (Electrical Engineers without normal budget constraints) have changed their minds along the way.
what will be the specification of mppt charge controller use to charge 48 v ,90Ah lithium ion battery with the 5 solar panel of 50 watt each connect in parellel.
Sudhanshu Ranjan You typically need the solar array to be at a higher voltage than the battery bank unless you have a boosting charge controller. Put the panels in series. 48V 5A
Garret, thank you for nice explanation. So, the numbers on Victron controller indicates: input Voltage (what's coming from solar panels) and output Amperage (what's going into batteries). Right? Or it's both - Maximum IN and OUT is: 100V, 30A? Or it's 100V@30A?
Great video! Good rule of thumb suggestions. Best video on controllers that I have seen. I have 2 renogy 270 watt solar panels. I believe RNG 270 pg 1. The back says it’s 38 volts. In this video, the rule of thumb of over 300 watts I should get a mppt. I’m at 270 and so maybe pwm is ok. (Unless I series the panels someday) Does it being a 38 volt panel affect what charge controller I should get? Luckily thanks to your video and the rule of thumb (first number on the Victron is the max voltage) I think I’ll need the Victron 100/30? The panel says 9 amps so in series or parallel I should be good?
Because of the higher voltage, you will need an MPPT controller to step that down for charging a 12V battery bank. If this is a mobile application, I would go with parallel connections. 2 x 270 x 0.9 / 12 = 40.5A. You could use the 100/30, but you will likely get clipping on bright days. Another option would be the 100/50 if you didn’t want any clipping. If I spent most my time under 45 degrees latitude, I would go with the 100/50. Otherwise, the Victron SmartSolar MPPT 100/30 would be fine.
If my rv has one 140 watt panel with 10 gauge wire going down to a 40 amp mppt charge controller and a agm battery bank, could I add 2 100 watt panels in parallel or would I need to wire all three panels in series because of the 10 gauge wire going down to my controller? I know in series the amps are limited to the amp rating of the smallest panel, but wasn't sure if the 10 gauge wire would work ok for the three panels in parallel. Or should I just add one 100 watt panel to the 140, if done in parallel? I guess what I am asking is there a rule of thumb for how much solar wattage in parallel a 10 gauge factory pre wire should be limited to assuming normal drop from roof down to solar controller? Thanks
I wouldn’t series the panels because the mixed Immp is too extreme. Unfortunately, I would be hesitant to add another parallel panel to your existing 10ga. We don’t like to go over 200W on 10ga. I suggest trying to find a panel with a similar Impp to put in series, rather than 100W panels. You might be able to find a150W panel. That would be close enough. But your best bet is to route new cable. Play it safe and go with 4ga or 6ga. Good luck. Hopefully manufacturers will start getting more realistic with their prewires.
Hi, when charging camper batteries it is often mentioned that the charge amperage should not be to high or the battery life span will be reduced. Am I right in assuming that a victron 100/30 is charging batteries at an initial rate of 30 amps, which for many campers is considered to high. What are your thoughts. Kind regards
The charging current output of the 100/30 will be 30A DC. I don’t know of any RV batteries where this is an issue. You might be thinking of 30A AC, which is a totally different thing. For example, a popular Battle Born battery can charge at 50A. Many people have two of these, so that would mean the system can handle 100A of charge.
I have a Hardened Power Systems Juice Box G3 inverter with four upgraded AmpedOutdoors 12v 15ah LifePo4 batteries “in parallel”. What do you recommend I enter for each Victron SmartSolar 75 / 15 charge controller settings below. Also I’m only using 125 to 150-ish Watts of solar to charge up my Juice Box. Max charge current = Absorption voltage = Float voltage =
Our technician recommends the following: Max charge current = 15a Absorption voltage = 14.5v Float voltage =13.7v Of note: low-temperature cut-out does not seem to be mentioned in the manual. I recommend setting this to 32f in the charge controller.
Thank you for this video. I am not sure I grasped everything and want to be sure before I buy the MPPT controller but understand because I exceed 300w I should use a MPPT vs PWM. I am using six 100w panels @ 12v each to charge a 12v 100Ah Battleborn LiFePO4 battery. My total Open Circuit Voltage is 127.2v and Short Circuit Current 6.02 amps. 600w x 90% = 540 and I should divide that by the charging voltage? If I grasp this correctly with a 12v battery I would need a 45a MPPT. Would a 40a work without damaging the battery or controller? I am located in NY state with low sun and not sure if I should use 3 in series then parellel to the battery or if I should just go in a series? Thank you, I appreciate your help and this video!
If we were installing six 100W panels, we would connect them all in parallel with 10ga to a combiner box, then we would route 4ga from the combiner box to a switch, then to the charge controller (Victron SmartSolar MPPT 100/50) then continue with 4ga to a 60A DC breaker, then to your battery system. You would be fine with a 45A charge controller. A PWM controller is fine if all the panels are in parallel, but an MPPT charge controller would be better. I wouldn’t connect all the panels in series, because that would take you over 100Voc which is above the limit of most 45-50A charge controllers. A 3x2 or 2x3 configuration is also acceptable (and preferable if you can’t use thick 4ga cable) but it doesn’t handle partial shade as well. I hope this helps.
@@GarretTowneAMS Yes, that is very helpful! I truly appreciate the help and reply. I watched some of your installation videos and was more than confident that I could trust your advice. You folks do great work. I was amazed at the Airstream install! Thanks again...
Hi, great explanation I have a victron 100/50 and 2 x350w solar panels, but only 1 on my caravan roof so far, the max watts it has gone to is only 190watts which I thought it would have been more, so I am going to put the second panel up. My question to you is over 5 meters what size cable I need to join and run the cable to the controller from the panels, as the controller might not fit the diameter of the cable that is needed for the 500watts all though it handles 500 watts? thanks Wes
I would put the panels in parallel, then go to 4ga down to the controller, and 4ga to the batteries. 6ga will work too (and fit in the controller terminals better) but we like to oversize slightly. I hope this helps.
Great information. I bought second hand panels and batteries: 6 panels for a total of 1020 W (12V), parallel wired, and 1140 AH of deep cycle lead batteries (6 of SBS-190F). I calculated 78A charging current needed. Since the system is old, (1) can I get away with a 70 A controller, and (2) is a PWM controller sufficient?
I would feel comfortable with a 70A controller on that. Make sure you don't exceed the input current or input voltage limits. With a system that big, I would avoid PWM. Get a Victron 150/70.
I've tried my hardest not to ask and just to do enough research to figure it out but I guess confirmation would be nice too haha. I have 800W of solar (4 x 200W) that I'm planning on wiring in series-parallel and a 40a charge controller. In just about every video or blog, people recommend at least 70-80a charge controllers but I think that's because they're usually expecting people to wire in series. Since I'm wiring in series-parallel my total amps would be 20.4 and total volts would be 48.6 (each panel has a VOC of 24.3 V & ISC 10.2 A)so it seems like I should be fine with a 40a charge controller. It's all Rich Solar brand. Thoughts?
Charge controllers are rated on output current, not input current, so your array configuration doesn’t matter, four panels is too hot for the controller. You might get 60A of charging current, and that’s not a good match a 40A controller. Put all your panels in series and you still have too much output current. Good luck with your project.
I have 12 x 250 watt solar panels and my system is currently running on 24volt inverter. I’m looking to change my inverter to a 48volt system as I anticipate to increase my load to 6800watts. Can I get a 150/85 charge controller to run (configure) for my system now at 24volts and later use it with 48volt inverter?
Losses (line losses, panel angle, age of panels) need to be considered also. This is just an example, please don't try this at home! I use 8x100 watts panels, in series (2 years old system) open volts 21.6 x 8 = 172 - losses in my system = 35 volts, 25 feet marine 12 gauge wire, controller voltage hovers around 130-140 at peak times in cool sunny days, and in Texas, and generates approx. 3.5 kW with a 600 watts GTI, very impressive. Keep your system cool is very important.
My experience with quite a few controllers is the inability to input the parameters needed for a particular battery chemistry. Some even state you can input 'user' settings but often do not allow such after installed. I do like some of the higher priced ones in that they are more accurate and allow more user input. Batteries are freakishly expensive and using a cheaper controller seems like a foolish thing to do.
Very informative video! For a 12v system, 4x100ah Lithium, 4x210watt panels (Vmp:22.4, Voc 24.9, Imp 9.37, Isc 9.85), would the 100/50 be a good choice? If so, would the 100/50 still be good if 2 more 210 watt panels were added? I’m thinking 3s2p config for the panels.
Assuming your batteries are in parallel, for a 12V system, yes, you can add another 100W panel. If you add a third panel, it will still work, but you might get output clipping on bright days.
I really need your help. My solar panel details are as below. Voltage: Voltage at Max Power (Vmax) - 37.39V, Open Circuit Voltage (Voc) - 46.38V Current: Current at Max Power (imax) - 8.20A, Short Circuit Current (isc) - 8.96A I have a 24 v 11 ah lithium ion battery. Please suggest me the suitable mppt controller rating. I would also like to ask if it is possible to charge the batteries at max 4 amps. Not more. Is that possible in mppt?
@@GarretTowneAMS what would determine if we hook up panels in series vs parallel? Thanks! I just found you and am grateful of the concise information! I'm trying to get a controller choice nailed down. MPPT, but I've got 2 agm batteries, only 400 watts=30A, BUT panels say 12-24V which is confusing me. Help! Lol thank you
@@heatherk8931 Ignore the 12-24V on the panels. It doesn't mean anything useful. Your panels likely operate at 18V, which in parallel is ideal for a 12V battery bank. Put the panels in parallel to give them optimal performance under partial shade. Use 6ga after the panels are combined to the charge controller, and 6ga from the charge controller to the battery.
Thank you for the great informative video. However I need a clarification on the startup voltage and Open circuit voltage. For example, if I use 3 strings each with 3 SHARP 330W PV modules (Open Circuit Voltage (Voc) = 46.2V, Short circuit current (I sc) = 9.33A, Voltage at Point of Max. Power(Vmpp)=37.8V ) and I use Smart Solar Charge Controller MPPT 150/70 (150V absolute maximum coldest conditions, 145V start-up and operating maximum), will the Charge Controller startup or not? Thank you
If you are sure you won't get cold enough that the 150V limit will be problem, the short circuit current won't be an issue either. If you put this on a 12V or 24V battery bank you will have a lot of output clipping. An array like that has the potential to charge at about 220A on 12V. With that controller, you will only get 70A.
I heard that cold weather can increase current so the controller should be sized 25% larger than what is needed. You are saying to mult by 0.9 and not 1.25. So 3 100w panels in series (22.5 V each, open current 5.75A each) would be fine for the 100 / 30 controller?
Scott Wood I would feel fine with five 100W panels on a Victron SmartSolar MPPT 100/30. 500W may result in some clipping of power on bright days, but nothing harmful. Cold does increase voltage output of a panel, but you certainly don’t need to oversize for cold weather.
Hi hoping you could help me with this. 12V System ! Panels =250w Vmp =30.1V Voc =37.3 Imp =8.31A Isc =8.71A Charge Controller is a Renogy 60A MTTP. Nominal Voltage: 12V/24V/36V/48V Auto Recognition (for non-lithium batteries) Rated Charge Current: 60A Rated Load Current: 20A Max. PV Input Power: 800W/12V; 1600W/24V; 2400W/36V; 3200W/48V Max. PV Input Voltage: 150 VDC (25°C), 140VDC (-25°C) Battery's= x2 115AH AGM 12v Wired in Parallel Running a Companion Fridge 24/7 avg power consumption is 0.09amp What is the maximum panels i can use in any given wiring configuration to get the maximum out of my controller and battery's?
60A / (250W x .9 / 12.8V) = 3.5 You can play it safe and use three panels in parallel, or go up to four panels if you don’t mind a little output clipping on bright days.
Sounds like you have 400Ah of Lead-acid batteries and want to use a 100W solar panel? A 30A charge controller will definitely work. You could get away with something as small as a 5A charge controller.
I have 3 190 watt panels and a Victron 100/50 charg controller. Can I safely add another a190 watt panel? My panels are now hooked up in series. Thank you
What’s the best Victron controller i can use on 3 260 watt panels running in parallel on 2 140amp leisure battery’s voc at 38 short circuit current at 8.89
Hello, thanks for the informative videos. I have a question. if I have purchased one victron bluesolar 360wp 24 volt mono solar panel which Victron charger from Victron do I recommend? I want this with built-in bluetooth. Ore another scenario If I understand correctly, I can charge two 12 volt 17Ah batteries in series with a powerful Victron charger without damaging the battery? The solar panel used is the Victron panel mentioned above. This may sound ridiculous but I want to buy more solar panels and batteries later. Greatings Jean-Pierre
If you are charging a 24V battery bank, you can use a Victron SmartSolar 75/15 controller with that panel. If your battery bank is 12V, you'll need a 30A controller. Also, 17Ah seems pretty small. Make sure the batteries can handle 15A of charging current. My guess is that they can't. You might want to get larger batteries.
@@GarretTowneAMS Thank you Garret for this clear answer. Continue making these informative videos. These are for me the best videos about solar panels and battery chargers. I love your channel thank you. I wish you success in all you do. regards Jean-Pierre
Hello Garret here I am back, if I buy two victron AGM batteries of 12 volts 240Ah and connect them in series (24 volts) How many victron bluesolar 360wp 24 volt mono solar panel do I need. Minimum and maximum panels and which Victron charger do I need to charge these batteries? I would also buy the 24 volt to 230v 1200 watt inverter. Am I doing the right thing with this? Please provide your expert advice. regards Jean-Pierre
@@Wirelessinfopuntbe The only reason you would want a certain wattage of solar array relative to battery bank capacity is to make sure your solar array is capable of topping your batteries off at least once per week on the low end, and on the high end, just making sure your charger isn’t in float mode (i.e. battery bank is full all the time) indicating that you spent too much on solar that isn’t operating at its full potential. You can use a single panel, assuming it has a Vmpp over 36V. Or, you could have four of those panels (connected in series pairs). You probably wouldn’t benefit much beyond four. If you had four panels, you would want a 100/50 controller. With a single panel the 75/15 will work.
i have the 100/20 and my panels showing 33v direct open circuit summer sunshine.. i want to add 3 series and count on long cabling voltage drop to lower at safer voltage numbers... is it possible to count on voltage drop and add that 3rd panel ? 2 panels close to 70volts open circuit i guess little more in winter temperatures ... if i make that long route cabling the panels up on the roof 30 foots cable .. is it possible with that voltage drop to add 3 series and no damage the charger ? i m going to test with multi meter and keep it at safe voltage numbers but what is the best asking production i want to have and earn all longivity of the charge controler ? ? ? ? 70% ? 80% ? any long term use of them ,,, usefull tip > >> ? thanks
What is the total wattage you have and the total wattage you want to have? Let me know, and I'll tell you what you can do. As long as you don't exceed 100V or 35A on the input, it will work.
Tkyou so much...i will go whit 150/ 70. Can you help me whit the blue print .how to conet 8 solar panel 435w. Can i orde mppt in you store. ..also this mppt is good for lithium battery. Tkyou
Please can you suggest a charge controller that I can use with a polycrystalline panel of max power 20w, current max power 1.15A, voltage max. Power 17.8v, short circuit current 1.19A, open circuit voltage 21.7v. thank you
hi can i use that solar charger controller by giving AC input of 220v power to the transformer and 24v or 12v dc output to charge the batteries? instead of getting the power from PV panel. thanks...
I have a pwm control box with a single 100W panel hooked up to a single 12v normal car battery...it will not charge my battery - in fact it discharges my battery Any ideas ??? HELP !!!
My first guess would be a bad controller, especially since it seems to discharge your battery. Next would be a bad panel, or a bad connection. Good luck.
Ok, I have watched so many videos on solar and still don’t quite understand, I have 4 100W panels, 1000W pure sine wave inverter, I did buy a charge controller but it is not a MPPT so I sent it back, bought a reset circuit breaker and someone said I needed a fuse also, have 1 100ah lithium battery, what I am trying to do is hook up to ru a freezer and refrigerator and nothing else, do I need to use all 4 panels? Should I have 2 batteries, I can’t get anyone to answer me, l am 74, trying to get ready for hurricane season, Thanks
There are a lot of crazy people on the internet talking nonsense about solar. I understand the frustration. You will want all four panels connected in parallel. A breaker and a fuse do the same thing. We would use a 40A breaker between the charge controller and the battery bank. Your system will work with one battery, it’s just a matter of how much energy you want to store. You can add a second battery later if you want more energy.
Hi Gary. I have two 160w panels going through a BlueSky 2000e controller. 4agm 12v batteries totalling 760ah’s. On a sunny day the batteries never peak to over 13v when my output setting is 13.8. Will I get better output output with Victron 100/30 controller? Also pros and cons of panels wired in parallel or series? Thanks
Ian Mayo I don’t the charge controller is the weak link in your system. I think your ratio of solar wattage to battery amp-hours might be the problem. You don’t have enough solar wattage. I would get two more panels (which would necessitate a 50A controller). If you don’t do this soon, your batteries will suffer.
Hello, I got 8 solar panels wire in parallel. 250watt ,37.2 voc ,and 8.3 a each panel. So should I buy Victron Energy BlueSolar MPPT TR 150V 70 amp 12/24/36/48-Volt Solar Charge Controller? And should I do the batteries in series to make 36v? Or I can still do it as 12v. Please advise. Thanks in advance.
8 x 250W = 2000W, 2000W x 0.9 / 12V = 150A. You would need two of those 150/70 charge controllers if you are using a 12V battery bank. You can get away with a single charge controller if you put them on a 24V battery bank. I recommend putting the panels in series-pairs, not all parallel.
![Sizing an MPPT Charge Controller [Basics]](/img/n.gif)
Outstanding video. Very simple. I’m retired from the Electrical/Mechanical work.
about 50 hours of research in and this is one of the best detailed but simply explained videos yet.!! thanks :)
not my real name Thanks! I’m about nine years in and learning new stuff every day.
'Not my real name'....I was thinking the same....
Folks there are some very good charge controllers out there But I recently purchased a VICTRON CHARGE CONTROLLER 100-30 There are no words to explain this product but I can tell you in my words that the quality & the workmanship of this product is second to none. I am so taken back on how beautifully this equipment performs. The reviews of this product is right on and I highly recommend on a scale 1 to 10 9-1/2 seven STAR
Nice to hear from a professional - electrical engineer Garret Towne. Thank you Sir..!
Thank you for speaking on over sizing the solar charge controller.
Best video on UA-cam for solar!
Don't freak out but it's 2am and I would hug you!!!! This video was perfect! I spent hours with videos that were 15 minutes long but the information could have been said in 1 minute AND they were a tad rubbish and confusing. This video was at the perfect pace and order to furnish organized information and the formula was like a Father's Day present to me! Thanks! Specifically because I bought a camper and it had a factory installed solar panel, the additional "plug" on the frame reads "Zamp", so I bought another Zamp panel, the exact one you showed. I did not check he operating roof one which I later learned was a 200W/43.83V/4.54A Sonali Solar!
I was worried that they were different but then realized I could wire them in series to add the Zamp 18V voltage but since my Victron MPPT is 75V/15A. I was worried on exceeding the Amperage...but I read in comments that as long as the voltage stays under the 75V (my panel series add up to 62V) then the controller will limit the excess (could go to 24A as it trims the voltage to 14V) to 15 amps on peak sun hours. In other words, it would choke if too much voltage is fed to it but it can shave off any amps over 15. Hence, I thought about the 100V 20A to take advantage of the 24A potential, but I was worried the wires to the battery may overheat since they are concealed in the wall and I cannot figure out their gauge. I know that electrical Romex, even the 15A white one can handle 20A, just like outlets and switches, but I am not sure if the wires the factory used allow a tad more occasional juice. The tip looks like an 8AWG but it could be a 10AWG.
Anyhow!!!! THANK YOU!!!! WELL DONE!!! you are a hidden treasure in the UA-cam jungle!
Send me an email and we can go over your situation in more detail. There may be more efficient solutions. Garret@amsolar.com
Now that I’m in my office, I have a longer response. If you put a Zamp panel in series with the Sonali panel, you will have a functional system that won’t fry your charge controller. You get a slight mismatch in current (4.54A vs. 5.00A) that will reduce efficiency slightly, but you’ll still have much more output than you would get with either panel by itself. As for wire sizes, the input to the controller can be small. 10ga would be fine. Output would ideally be 10ga. If you are interested, have a much more comprehensive explanation of solar system design here: amsolar.com/solar-charger-design
@@GarretTowneAMS You are the Man! it is working like a charm, and I am extremely proud (perhaps OCD) that the panel is perfectly aligned, that the cables re tidy and even the sealant is well shaped, ha! but most important is that the system is working like a charm and I see how it limits to 15A in the output, so I guess a new MPPT 100/20 should be beneficial.
I truly thank you for the assistance and when the time comes I will buy the rest of the equipment and upgrades (if you ship to Fairlawn, Ohio which I am sure you do). I tried to upload pictures but as you already know I am technically challenged, LOL
@@asuarezjd We do ship to Ohio. I'm glad things are working for you. Thanks.
Yup, many hours and days on UA-cam researching and this video, by far has taught me the most. Thank you for sharing your knowledge.
Woow 🤩 after having made a million hours of research in about solar systems and stuff, that video is by far the most simple explicit professional technical way of explaining how charge controllers works!!! Thank you from France Garrett ;)
This video is fantastic! I was feeling super lost before this video. Love the math and diagram portion. Big thanks!
Very helpful. I have been looking for a simple concise explanation of sizing and this was exactly what I needed. Thank you.
From Uganda, this is the best Video i have watched on Solar systems. Thanks AM
Bloody brilliant - thanks so much (even if I had to watch it 50+ times to get it in my tiny brain! 😉).
Thanks for the math lesson. That's exactly what I've been looking for. I just bought a 100/50 charge controller. So 4 100 watt panels should safely do it.
Victron depends on your battery voltage if you using 12v then yea 400w, 24v 800w, 48v 1600w etc
This was a great explanation. I struggle with all the various calculations, and you really laid it out so I can make sense of it.
so frick'n helpful man, it's little video's like this that go such a long way...thank you so much for sharing, so clean and concise, I understand now!
You are a wise photovoltaic men. Thanks for the explanation
Thank you for the first informative explanation of Victron MPPT solar controllers I’ve viewed yet! Easy, simple to understand and very worthwhile.
Great information. Thanks
Great Video guys - all the best from Australia :)
Thank you
Very useful - thanks!
Brilliant explanation. Thanks for a good video
Thank you. I'm working on a new video covering this topic with more details. If you're curious, I have it written out here: amsolar.com/solar-charger-design
Thank you Garret. So very well explained.You cleared up so much confusion.
Fantastic video. Thanks for the easy equation. Super helpful
The video super helpful, thank you and You're the best Teacher!
Made my day. Thanks.
Thanks for the formula. Now it actually makes sense.
Super video !
Hi from Aussie.. Really Great info A huge help.. Easy to listen to well done... and a big thanks for ( NOT PLAYING USELESS LOUD MUSIC IN THE BACK GROUND )
5....Stars Liked and Subscribed
Clearly you didn't watch the video! The useless music begins at 2:43
Wow thank you so much for that video! it's awesome and answeres every single question I had so far :)
Brilliant video
This is Awesome! No one speaks about input and output current relative to the amp ratings on these controllers. I also assumed series wiring would allow room for a larger array on a smaller controller. Wx90%/v=A. Love it! Thank you, very informative.
You can wire panels in series, but you must use a MPPT controller, not a cheaper PWM controller. Be sure to stay below the total voltage of your mppt charge controller though. If you are going to wire in series, you need to understand the math involved in electricity so that you keep you equipment and yourself safe.
That, I am already aware of but I'm sure that info will be useful to others. Thanks Steve
absolutely nailed it, thank you
Super informative!! Many thanks. You saved me hours of research!
Thank you for going over that formula, I almost under spec'd (3x) 180 watt / 9 amp panels as only being 27 amps, not 40.5 amps. That would have been a big mistake.
Its a common mistake. You likely wouldn't have fried anything, but you would have experienced some current limiting on bright days.
Very well explained Thank You
great information there, very helpfull. thank you
Thanks for making this video! ❤
Just regards the rated output current , I've got a 100/20 Victron , its set to charge 12v batteries but it can charge 24v batteries too. As far as I know it can charge to that max 20 amp output current regardless if set to 12v or 24v batteries, so meaning you can put in roughly double the power / wattage into a 24v battery system compared to a 12v system.using the same MPPT controller , providing the solar panels are up to it.
bradley c. That is true, but 24V systems require 24V inverters, DC converters for 12V loads and alternator charging becomes more complicated.
You should mention that at 4:00, the v in your calculation is based on the current voltage of the battery at that moment in time, not some generic '12 volt bank" as you describe it. It's a critical distinction.
I know where you are coming from on this, and I agree that it would tighten up one aspect of the formula, but 90% is probably even more inaccurate, since it is supposed to encompass the wide range of sunlight conditions. I just use it as a rough rule of thumb and frequently oversize solar arrays (which is what would happen if you raised 12V to 14.4V). You can look at charge controller selection in two ways 1) Design it super conservatively in a way that no clipping is allow (maybe end up spending a little more than you needed to on the controller) or, 2) Ball park it, maybe oversize your array, and experience some clipping on bright days. On most of the charge controllers we use, an oversized array isn’t going to harm the controller, it will just limit the charging current on very bright days. Thank you for noticing that.
A 12 volt bank at 12 volt is what we see as empty, Charging to bulk mode is 14,4 volts , so using a mppt gives you even more amp input at low battery, just when you need it, And the percentage will drop down a bit by higher battery voltages, when the battery is gettig fully charged, Messuring from the over voltage you have present in the array, it wil work even better at lower battery voltage, producing more charge amps. (only iff you use the mppt controller) (its not the case in pwm controllers)
@@MrBugsier5 You are correct, but the point is that this is just a quick rule of thumb calculation. I could just as easily use 14.4V and 75% and come up with the same values. Variations in solar irradiance introduce more inaccuracy to the calculations than not getting the exact charging voltage and efficiency factor.
@@GarretTowneAMS and Wx.90÷12 is easier math to remember
Very well explained!! Keep doing good work!
This is a very good description of charge controllers. However, your wattage calculations are all based on having a 12V battery system. If you have 24 volt batteries, the wattages double, and with 48 volt batteries, they double again. For instance, your 30 amp (maximum output current) Victron charge controller with a 12 V battery will output at most 360 watts, give or take a bit based on the actual operating voltage of the battery. 400 watts or so of solar panels would be appropriate. With a 24 volt battery system, that same 30 Amps will give 720 watts, and with a 48 volt battery system, that 30 amp output will give 1440 watts, so total solar panel output power can be increased accordingly.
The charge controller will charge any of these systems because the 30 amp maximum current applies to all of the battery voltages. The Victron charge controller is even smart enough to auto detect the battery system voltage!
This is an important point that wasn't covered in this video.
It’s been a long time since I posted this video and in that time we have done a lot more 24V systems. You are absolutely right. Don’t use “12” in all the calculations. If you have a 24V or 48V battery bank, use “24” or “48”. A controller will support twice the solar wattage at 24V than it will at 12V. When I get a chance, I plan on making a revised video where I also bring up input current limits, another issue missed on this video.
I love this informative video and I admit i'm a newbie at solar systems, but other videos / tutorials ive seen show that you can get closer to 1400 watts or more running on a 150v /60 amp charge controller as long as you're running a 24 volt solar panels / 24v battery, etc ? I realize that you said that the calculations arent black and white, but i'm confused because of the big gap between less than a thousand and 1400+ . I bet i'm missing something really obvious.
This was the best video I've seen yet on this.. no one else references the array wattage. So a 1200w array would need a 150/100 correct?
Yes, make sure you don’t exceed 150Voc or an Isc of 70A. I’m actually working on an updated version of this video. I hope to have it out in two weeks.
Thanks for a clear, simple video. Finally, someone prepared to de-mystify some of the "shrouded-in-secrecy" off-grid setup information. Frustratingly, the only information available on internet forums seems to be pitched at mountain-top level for advanced users only. Do you happen to know which Victron models have the bluetooth function? Mine is the Easy Solar 170/50 MPPT, and when I tried to scan it with the bluetooth turned on and using the Victron Connect app, I get "no device found".
If the Victron controller has "Smart" in the name, it has built-in Bluetooth. Otherwise, check out the Victron Bluetooth dongle that can plug into a VE.Direct port.
Great video...thanks!!
What we really need: A useful charge controller comparison. Measure the output of the not yet connected panel, the voltage at the input with the panel connected, and the voltage to the battery and load from the controller. Every eBay Price lowest first controller I have tested knocks the panel down to 11.8 at the input and sends that to the battery. No amount of control changing will bring that up.
Thanks for the input. What are some controllers you would like to see compared? This channel is an offshoot of a business that warranties work for the life of the install and provides high level tech support to customers that have issues. Because of that, we have to be very careful about the products we carry, and we feel Victron does the best job of keeping our non-revenue producing support (tech and warranty) to a minimum. So, we don’t typically have a variety of controllers around.
The output of a panel that isn’t connected to anything would be zero. The potential output would vary based on irradiance, temperature, and the resistance of whatever the panel is connected to (i.e. the voltage at which current is being drawn).
As for the rest of your comment, it sounds like you are dealing with a PWM charge controller. PWM stands for Pulse Width Modulation, and PWM controllers connect the panel directly to the battery. The connection is pulsed, with on/off cycles based on the voltage of the battery (roughly the charge status). If you are getting 11.8V on the panel side, that’s because your battery is roughly 11.8V, and the battery forces the panel to operate at that voltage with a PWM controller. There is nothing wrong with this. It works, but it isn’t as efficient as an MPPT charge controller that lets the panel operate at a more efficient voltage (usually 18V depending on the panel) and transforms that higher voltage down to something that is safe for your battery.
Thanks
super helpful, thank you!!
Thanks alot!😊 Appreciate the indepth info!❤️
Good video. Lots of info!
This was very helpful especially the bit about too much solar. Does the array wattage equation apply to pwm? If i use 160W panel, the equation says 12A. But the short circuit voltage is only 8.7A. What I really want is to get as close as possible to 10A for my battery.
very super messages, please help hiveme a mppt charge controllar ,thank you
Thank u very much 4 ur response.Kind of u. I have a 5 panels of 100 watts each.charge controller seems 2 b local made provided by solar installer.it is 12v/50amps. Don't know y it heats up
If they are all connected in parallel and you are using at least 6ga wire, you shouldn't have any issues. I would feel comfortable using a 30A controller on that. Maybe you got a defective charge controller.
My total Load is 520watts . Wat solar panels, inverter and solar charger controller required for the above load to last for atleast 5hrs in a day
If you use 520W for 5h per day, that works out to 2600Wh/day. For easy math, we tell people that 1W of solar will give them about 3Wh per day in decent sun. Obviously this can vary depending on a number of variables, but you would be looking at about 900W of solar. I might start with 5x 200W panels on an 85A charge controller. If you need more solar, you’ll have room on the controller for a 6th panel. I would use at least 300Ah of lithium or 600Ah of AGM batteries for this.
@@GarretTowneAMS thnxs
Great video. I am building my system and will have 2-100 watt panels, what charge controller would I need? I won't be expanding the system
My favorite is the Victron SmartSolar MPPT 75/15.
@@GarretTowneAMS Thank you for your response. I forgot to add I will be using 2- 6 volt AGM Deep Cycle golf cart batteries. Would that be ok?
Ms. Sowlo Yes, those are compatible.
Great video, please make more. Quick question, some of the inverters have built in charge controllers , would your formula still work in that scenario ?
We haven’t worked with an inverter that has a built-in solar charge controller before, but I have heard of them. Make sure you actually have a SOLAR charge controller, not just a charger. If that is what you have, the formula would still work. I have several video scripts in the work, just not enough free time. We are insanely busy. Thank you.
Victron mppt charge controller is expensive, you can buy solar inverter of 3.2kw or 5kw having already Mppt technology in affordable price
Nice and very informative video , I didn't know that the Victron MPPT's just limit the current if there is over current ( I thought the fuse would blow ) . Thats very handy to know. Do they do the same with Over voltage? Say two 38V panels in series on a MPPT 70/15 Victron? thnx . What I miss in your video is that a good way to expand your system with the same charge controller is increasing the Voltage from the battery pack. ( say 2 or more 12 volt batteries in series in stead of just one 12V, doubles the amount of watt going in, but the amps stay the same ) and besides that everything becomes more efficient with a higher battery voltage. Thnx
Unfortunately, over voltage will damage the charge controller and I believe it damages it in a way that is very obvious to the warranty department, letting them know you did not follow the rules. It is true that you can double the amount of solar on an array by doubling the battery bank voltage, but that makes alternator charging very difficult, you would have to get a new inverter and DC/DC converters for your DC loads. We have a lot of people come to us wanting 24V systems and all but two (Electrical Engineers without normal budget constraints) have changed their minds along the way.
what will be the specification of mppt charge controller use to charge 48 v ,90Ah lithium ion battery with the 5 solar panel of 50 watt each connect in parellel.
Sudhanshu Ranjan You typically need the solar array to be at a higher voltage than the battery bank unless you have a boosting charge controller. Put the panels in series. 48V 5A
Garret, thank you for nice explanation.
So, the numbers on Victron controller indicates: input Voltage (what's coming from solar panels) and output Amperage (what's going into batteries). Right?
Or it's both - Maximum IN and OUT is: 100V, 30A? Or it's 100V@30A?
Input 100V max, output is limited to 30A. You can overload the output and it will clip, but don’t exceed the input voltage. Does this help?
Great video! Good rule of thumb suggestions. Best video on controllers that I have seen.
I have 2 renogy 270 watt solar panels. I believe RNG 270 pg 1.
The back says it’s 38 volts.
In this video, the rule of thumb of over 300 watts I should get a mppt. I’m at 270 and so maybe pwm is ok. (Unless I series the panels someday) Does it being a
38 volt panel affect what charge controller I should get?
Luckily thanks to your video and the rule of thumb (first number on the Victron is the max voltage) I think I’ll need the Victron 100/30? The panel says 9 amps so in series or parallel I should be good?
Because of the higher voltage, you will need an MPPT controller to step that down for charging a 12V battery bank. If this is a mobile application, I would go with parallel connections. 2 x 270 x 0.9 / 12 = 40.5A. You could use the 100/30, but you will likely get clipping on bright days. Another option would be the 100/50 if you didn’t want any clipping. If I spent most my time under 45 degrees latitude, I would go with the 100/50. Otherwise, the Victron SmartSolar MPPT 100/30 would be fine.
So if I want to run a top load fridge that is 45watts/3.75amps and charge a cell phone how many panels should I use?
I would start out with about 300W on a 30A charge controller. If the 300W isn't enough, that charge controller will give you room to add more.
If my rv has one 140 watt panel with 10 gauge wire going down to a 40 amp mppt charge controller and a agm battery bank, could I add 2 100 watt panels in parallel or would I need to wire all three panels in series because of the 10 gauge wire going down to my controller? I know in series the amps are limited to the amp rating of the smallest panel, but wasn't sure if the 10 gauge wire would work ok for the three panels in parallel. Or should I just add one 100 watt panel to the 140, if done in parallel? I guess what I am asking is there a rule of thumb for how much solar wattage in parallel a 10 gauge factory pre wire should be limited to assuming normal drop from roof down to solar controller? Thanks
I wouldn’t series the panels because the mixed Immp is too extreme. Unfortunately, I would be hesitant to add another parallel panel to your existing 10ga. We don’t like to go over 200W on 10ga. I suggest trying to find a panel with a similar Impp to put in series, rather than 100W panels. You might be able to find a150W panel. That would be close enough. But your best bet is to route new cable. Play it safe and go with 4ga or 6ga. Good luck. Hopefully manufacturers will start getting more realistic with their prewires.
Hi, when charging camper batteries it is often mentioned that the charge amperage should not be to high or the battery life span will be reduced. Am I right in assuming that a victron 100/30 is charging batteries at an initial rate of 30 amps, which for many campers is considered to high. What are your thoughts. Kind regards
The charging current output of the 100/30 will be 30A DC. I don’t know of any RV batteries where this is an issue. You might be thinking of 30A AC, which is a totally different thing. For example, a popular Battle Born battery can charge at 50A. Many people have two of these, so that would mean the system can handle 100A of charge.
@@GarretTowneAMS Thank you for the advice.
I have a Hardened Power Systems Juice Box G3 inverter with four upgraded AmpedOutdoors 12v 15ah LifePo4 batteries “in parallel”. What do you recommend I enter for each Victron SmartSolar 75 / 15 charge controller settings below. Also I’m only using 125 to 150-ish Watts of solar to charge up my Juice Box.
Max charge current =
Absorption voltage =
Float voltage =
Our technician recommends the following:
Max charge current = 15a
Absorption voltage = 14.5v
Float voltage =13.7v
Of note: low-temperature cut-out does not seem to be mentioned in the manual. I recommend setting this to 32f in the charge controller.
Now a question sir, can two or more charge controller be used with a panel?
That is can charge controller be connected together
You can parallel PWM controllers on the same panel to two different battery banks, but don’t do it with MPPT controllers.
Thank you for this video. I am not sure I grasped everything and want to be sure before I buy the MPPT controller but understand because I exceed 300w I should use a MPPT vs PWM.
I am using six 100w panels @ 12v each to charge a 12v 100Ah Battleborn LiFePO4 battery. My total Open Circuit Voltage is 127.2v and Short Circuit Current 6.02 amps.
600w x 90% = 540 and I should divide that by the charging voltage? If I grasp this correctly with a 12v battery I would need a 45a MPPT. Would a 40a work without damaging the battery or controller? I am located in NY state with low sun and not sure if I should use 3 in series then parellel to the battery or if I should just go in a series? Thank you, I appreciate your help and this video!
If we were installing six 100W panels, we would connect them all in parallel with 10ga to a combiner box, then we would route 4ga from the combiner box to a switch, then to the charge controller (Victron SmartSolar MPPT 100/50) then continue with 4ga to a 60A DC breaker, then to your battery system.
You would be fine with a 45A charge controller. A PWM controller is fine if all the panels are in parallel, but an MPPT charge controller would be better. I wouldn’t connect all the panels in series, because that would take you over 100Voc which is above the limit of most 45-50A charge controllers. A 3x2 or 2x3 configuration is also acceptable (and preferable if you can’t use thick 4ga cable) but it doesn’t handle partial shade as well.
I hope this helps.
@@GarretTowneAMS Yes, that is very helpful! I truly appreciate the help and reply. I watched some of your installation videos and was more than confident that I could trust your advice. You folks do great work.
I was amazed at the Airstream install!
Thanks again...
charge controller must take some power itself, like inverters , wondering how much each type
That's a good question. We tested one (not Victron brand) about seven years ago and got about 5W. We'll try this again and post the results.
Good
Hi, great explanation I have a victron 100/50 and 2 x350w solar panels, but only 1 on my caravan roof so far, the max watts it has gone to is only 190watts which I thought it would have been more, so I am going to put the second panel up. My question to you is over 5 meters what size cable I need to join and run the cable to the controller from the panels, as the controller might not fit the diameter of the cable that is needed for the 500watts all though it handles 500 watts? thanks Wes
I would put the panels in parallel, then go to 4ga down to the controller, and 4ga to the batteries. 6ga will work too (and fit in the controller terminals better) but we like to oversize slightly. I hope this helps.
@@GarretTowneAMS It will thank you
@@GarretTowneAMS Sorry so are you mean 6AWG cable ?
@@wesleyblake8552 yes 6AWG will work.
Great information. I bought second hand panels and batteries: 6 panels for a total of 1020 W (12V), parallel wired, and 1140 AH of deep cycle lead batteries (6 of SBS-190F). I calculated 78A charging current needed. Since the system is old, (1) can I get away with a 70 A controller, and (2) is a PWM controller sufficient?
I would feel comfortable with a 70A controller on that. Make sure you don't exceed the input current or input voltage limits. With a system that big, I would avoid PWM. Get a Victron 150/70.
Thanks for the information - very much appreciated.
I've tried my hardest not to ask and just to do enough research to figure it out but I guess confirmation would be nice too haha. I have 800W of solar (4 x 200W) that I'm planning on wiring in series-parallel and a 40a charge controller. In just about every video or blog, people recommend at least 70-80a charge controllers but I think that's because they're usually expecting people to wire in series. Since I'm wiring in series-parallel my total amps would be 20.4 and total volts would be 48.6 (each panel has a VOC of 24.3 V & ISC 10.2 A)so it seems like I should be fine with a 40a charge controller. It's all Rich Solar brand. Thoughts?
Charge controllers are rated on output current, not input current, so your array configuration doesn’t matter, four panels is too hot for the controller. You might get 60A of charging current, and that’s not a good match a 40A controller. Put all your panels in series and you still have too much output current. Good luck with your project.
@@GarretTowneAMS Thank you so much! Super good to know! :)
I have 12 x 250 watt solar panels and my system is currently running on 24volt inverter. I’m looking to change my inverter to a 48volt system as I anticipate to increase my load to 6800watts. Can I get a 150/85 charge controller to run (configure) for my system now at 24volts and later use it with 48volt inverter?
Losses (line losses, panel angle, age of panels) need to be considered also. This is just an example, please don't try this at home! I use 8x100 watts panels, in series (2 years old system) open volts 21.6 x 8 = 172 - losses in my system = 35 volts, 25 feet marine 12 gauge wire, controller voltage hovers around 130-140 at peak times in cool sunny days, and in Texas, and generates approx. 3.5 kW with a 600 watts GTI, very impressive. Keep your system cool is very important.
My experience with quite a few controllers is the inability to input the parameters needed for a particular battery chemistry. Some even state you can input 'user' settings but often do not allow such after installed. I do like some of the higher priced ones in that they are more accurate and allow more user input. Batteries are freakishly expensive and using a cheaper controller seems like a foolish thing to do.
Very informative video! For a 12v system, 4x100ah Lithium, 4x210watt panels (Vmp:22.4, Voc 24.9, Imp 9.37, Isc 9.85), would the 100/50 be a good choice? If so, would the 100/50 still be good if 2 more 210 watt panels were added? I’m thinking 3s2p config for the panels.
4 x 210W x 0.9 / 12V = 63A, and 4 x 210W x 0.9 / 12V = 95A
If you want just four panels, get a 150/70. If you want six panels, get the 150/100.
@@GarretTowneAMS Thanks Garret.
I have a smartsolar charger it is MPPT 75 I 10. With a 100 watt solar panel. Can I add more solar panels to this? I have 2 12volt batteries.
Assuming your batteries are in parallel, for a 12V system, yes, you can add another 100W panel. If you add a third panel, it will still work, but you might get output clipping on bright days.
I really need your help.
My solar panel details are as below.
Voltage: Voltage at Max Power (Vmax) - 37.39V, Open Circuit Voltage (Voc) - 46.38V
Current: Current at Max Power (imax) - 8.20A, Short Circuit Current (isc) - 8.96A
I have a 24 v 11 ah lithium ion battery.
Please suggest me the suitable mppt controller rating.
I would also like to ask if it is possible to charge the batteries at max 4 amps. Not more. Is that possible in mppt?
For that watts of solar × 90% / voltage of charging = amps is the solar panels in series or parallel or it doesn't matter which?!
It doesn’t matter. The results are the same either way..
@@GarretTowneAMS what would determine if we hook up panels in series vs parallel? Thanks! I just found you and am grateful of the concise information! I'm trying to get a controller choice nailed down. MPPT, but I've got 2 agm batteries, only 400 watts=30A, BUT panels say 12-24V which is confusing me. Help! Lol thank you
@@heatherk8931 Ignore the 12-24V on the panels. It doesn't mean anything useful. Your panels likely operate at 18V, which in parallel is ideal for a 12V battery bank. Put the panels in parallel to give them optimal performance under partial shade. Use 6ga after the panels are combined to the charge controller, and 6ga from the charge controller to the battery.
Thank you for the great informative video.
However I need a clarification on the startup voltage and Open circuit voltage. For example, if I use 3 strings each with 3 SHARP 330W PV modules (Open Circuit Voltage (Voc) = 46.2V, Short circuit current (I sc) = 9.33A, Voltage at Point of Max. Power(Vmpp)=37.8V ) and I use Smart Solar Charge Controller MPPT 150/70 (150V absolute maximum coldest conditions, 145V start-up and operating maximum), will the Charge Controller startup or not?
Thank you
If you are sure you won't get cold enough that the 150V limit will be problem, the short circuit current won't be an issue either. If you put this on a 12V or 24V battery bank you will have a lot of output clipping. An array like that has the potential to charge at about 220A on 12V. With that controller, you will only get 70A.
@@garrettowne i am using 48V battery bank
I heard that cold weather can increase current so the controller should be sized 25% larger than what is needed. You are saying to mult by 0.9 and not 1.25. So 3 100w panels in series (22.5 V each, open current 5.75A each) would be fine for the 100 / 30 controller?
Scott Wood I would feel fine with five 100W panels on a Victron SmartSolar MPPT 100/30. 500W may result in some clipping of power on bright days, but nothing harmful. Cold does increase voltage output of a panel, but you certainly don’t need to oversize for cold weather.
Nice
Hi hoping you could help me with this. 12V System !
Panels =250w
Vmp =30.1V
Voc =37.3
Imp =8.31A
Isc =8.71A
Charge Controller is a Renogy 60A MTTP.
Nominal Voltage: 12V/24V/36V/48V Auto Recognition (for non-lithium batteries)
Rated Charge Current: 60A
Rated Load Current: 20A
Max. PV Input Power: 800W/12V; 1600W/24V; 2400W/36V; 3200W/48V
Max. PV Input Voltage: 150 VDC (25°C), 140VDC (-25°C)
Battery's= x2 115AH AGM 12v Wired in Parallel
Running a Companion Fridge 24/7 avg power consumption is 0.09amp
What is the maximum panels i can use in any given wiring configuration to get the maximum out of my controller and battery's?
60A / (250W x .9 / 12.8V) = 3.5
You can play it safe and use three panels in parallel, or go up to four panels if you don’t mind a little output clipping on bright days.
I have two 100 W solar panels wired in series to a 12 V battery what solar charger do you recommend right now I have a 100-15
The Victron SmartSolar 100/15 or 75/15 are good options.
I have 2 200 watt solar panel with a 12 volt output. What is the minimum size MPPT controller I can use for this array?😮
I recommend a 30A controller, like the Victron SmartSolar MPPT 100/30.
I have 4 100 watts liquid acid batteries will a 100 watt solar panel and a 30 watt charge willl it work
Sounds like you have 400Ah of Lead-acid batteries and want to use a 100W solar panel? A 30A charge controller will definitely work. You could get away with something as small as a 5A charge controller.
I have 3 190 watt panels and a Victron 100/50 charg controller. Can I safely add another a190 watt panel? My panels are now hooked up in series. Thank you
You can if you put your panels in parallel or series pairs. Definitely don’t add the fourth panel in series.
What’s the best Victron controller i can use on 3 260 watt panels running in parallel on 2 140amp leisure battery’s voc at 38 short circuit current at 8.89
Assuming a 12V battery bank, go with the 150/70.
Hello, thanks for the informative videos. I have a question.
if I have purchased one victron bluesolar 360wp 24 volt mono solar panel which Victron charger from Victron do I recommend? I want this with built-in bluetooth.
Ore another scenario
If I understand correctly, I can charge two 12 volt 17Ah batteries in series with a powerful Victron charger without damaging the battery?
The solar panel used is the Victron panel mentioned above.
This may sound ridiculous but I want to buy more solar panels and batteries later.
Greatings
Jean-Pierre
If you are charging a 24V battery bank, you can use a Victron SmartSolar 75/15 controller with that panel. If your battery bank is 12V, you'll need a 30A controller. Also, 17Ah seems pretty small. Make sure the batteries can handle 15A of charging current. My guess is that they can't. You might want to get larger batteries.
@@GarretTowneAMS Thank you Garret for this clear answer. Continue making these informative videos. These are for me the best videos about solar panels and battery chargers. I love your channel thank you.
I wish you success in all you do.
regards
Jean-Pierre
Hello Garret here I am back, if I buy two victron AGM batteries of 12 volts 240Ah and connect them in series (24 volts) How many victron bluesolar 360wp 24 volt mono solar panel do I need. Minimum and maximum panels and which Victron charger do I need to charge these batteries? I would also buy the 24 volt to 230v 1200 watt inverter. Am I doing the right thing with this?
Please provide your expert advice.
regards
Jean-Pierre
@@Wirelessinfopuntbe The only reason you would want a certain wattage of solar array relative to battery bank capacity is to make sure your solar array is capable of topping your batteries off at least once per week on the low end, and on the high end, just making sure your charger isn’t in float mode (i.e. battery bank is full all the time) indicating that you spent too much on solar that isn’t operating at its full potential. You can use a single panel, assuming it has a Vmpp over 36V. Or, you could have four of those panels (connected in series pairs). You probably wouldn’t benefit much beyond four. If you had four panels, you would want a 100/50 controller. With a single panel the 75/15 will work.
i have the 100/20 and my panels showing 33v direct open circuit summer sunshine.. i want to add 3 series and count on long cabling voltage drop to lower at safer voltage numbers... is it possible to count on voltage drop and add that 3rd panel ? 2 panels close to 70volts open circuit i guess little more in winter temperatures ... if i make that long route cabling the panels up on the roof 30 foots cable .. is it possible with that voltage drop to add 3 series and no damage the charger ? i m going to test with multi meter and keep it at safe voltage numbers but what is the best asking production i want to have and earn all longivity of the charge controler ? ? ? ? 70% ? 80% ? any long term use of them ,,, usefull tip > >> ? thanks
What is the total wattage you have and the total wattage you want to have? Let me know, and I'll tell you what you can do. As long as you don't exceed 100V or 35A on the input, it will work.
Tkyou so much...i will go whit 150/ 70. Can you help me whit the blue print .how to conet 8 solar panel 435w. Can i orde mppt in you store. ..also this mppt is good for lithium battery. Tkyou
If you place an order for the charge controller from AMSolar.com we can get you a wiring diagram. I assume you are in the US?
Please can you suggest a charge controller that I can use with a polycrystalline panel of max power 20w, current max power 1.15A, voltage max. Power 17.8v, short circuit current 1.19A, open circuit voltage 21.7v. thank you
At only 20W, any controller will work. Maybe a 5A PWM controller would be a good fit.
I HAVE A MPPT SOLAR MOT 7210A WILL IT BE TO SMALL FOR A 400 WATTS PANELS
hi can i use that solar charger controller by giving AC input of 220v power to the transformer and 24v or 12v dc output to charge the batteries? instead of getting the power from PV panel. thanks...
That won't work for a number of reasons. A better solution would be a Victron IP67 charger.
I have a pwm control box with a single 100W panel hooked up to a single 12v normal car battery...it will not charge my battery - in fact it discharges my battery
Any ideas ??? HELP !!!
My first guess would be a bad controller, especially since it seems to discharge your battery. Next would be a bad panel, or a bad connection. Good luck.
Ok, I have watched so many videos on solar and still don’t quite understand, I have 4 100W panels, 1000W pure sine wave inverter, I did buy a charge controller but it is not a MPPT so I sent it back, bought a reset circuit breaker and someone said I needed a fuse also, have 1 100ah lithium battery, what I am trying to do is hook up to ru a freezer and refrigerator and nothing else, do I need to use all 4 panels? Should I have 2 batteries, I can’t get anyone to answer me, l am 74, trying to get ready for hurricane season, Thanks
There are a lot of crazy people on the internet talking nonsense about solar. I understand the frustration. You will want all four panels connected in parallel. A breaker and a fuse do the same thing. We would use a 40A breaker between the charge controller and the battery bank. Your system will work with one battery, it’s just a matter of how much energy you want to store. You can add a second battery later if you want more energy.
But, of i charge a 24 volts battery i can have double the amps?
If you go from 12V to 24V, you can double the wattage, but amps would remain the same.
Hi Gary. I have two 160w panels going through a BlueSky 2000e controller. 4agm 12v batteries totalling 760ah’s. On a sunny day the batteries never peak to over 13v when my output setting is 13.8. Will I get better output output with Victron 100/30 controller? Also pros and cons of panels wired in parallel or series? Thanks
Ian Mayo I don’t the charge controller is the weak link in your system. I think your ratio of solar wattage to battery amp-hours might be the problem. You don’t have enough solar wattage. I would get two more panels (which would necessitate a 50A controller). If you don’t do this soon, your batteries will suffer.
Garret Towne Thanks Gary. For now would I better off removing a battery out of the system?
@@ianmayo6711 I would probably remove two batteries, as long as you can keep them maintained while not in use.
Hello, I got 8 solar panels wire in parallel. 250watt ,37.2 voc ,and 8.3 a each panel. So should I buy Victron Energy BlueSolar MPPT TR 150V 70 amp 12/24/36/48-Volt Solar Charge Controller? And should I do the batteries in series to make 36v? Or I can still do it as 12v. Please advise. Thanks in advance.
8 x 250W = 2000W, 2000W x 0.9 / 12V = 150A. You would need two of those 150/70 charge controllers if you are using a 12V battery bank. You can get away with a single charge controller if you put them on a 24V battery bank. I recommend putting the panels in series-pairs, not all parallel.