Sailboat Solar Power - Series vs. Parallel & Shading
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- Опубліковано 8 вер 2024
- Shade on Solar Panels SUCKS! If shading is unavoidable, choosing between Parallel & Series wiring is the MOST important thing to consider.
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We've had a few different solar installs over the years on our Motorhomes. We've done parallel wiring, we've done series wiring, we've had improperly installed panels that were shadowed by roof A/C units.
With the extreme expense associated with our Solar Panel install on our new Sailboat we thought: We need to know the difference between parallel vs series and how shading affects the solar output. In our typical fashion we're not claiming to be experts, or do a technically perfect test...but we've setup what we think is a semi-solid real world test to see how our solar panels will perform on the Catamaran. THE RESULTS LITERALLY BLEW US AWAY! (ok, maybe not literally)
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Speak to your supplier and ask for schematics of the panel internals. Specifically you want to know the "string" organisation and the number of bypass diodes present per panel. Very simply, typically cheaper panels have less bypass diodes, which means more losses when one cell craps out or is shaded.
For instance, in a perfect world, each cell would be protected by a bypass diode, as soon as the resistance of the cell increases (ie. via fault or in this case shading it) then the bypass diode (or shunt) enables the re-routing of the current around the circuit. Remember cells are wired in series to one another, so one cell dropping out without bypass diode protection will kill the string it belongs to ...
So, a "poor" panel with 72 cells in series (1x string of 72), might have one bypass diode (effectively bypassing the panel!), so a single cell shaded or damaged causes the whole string of 72 to go dark, the bypass kicks in and the whole panel is nulled, but power flows … a "better" (ie. more expensive) panel would arrange the 72 cells as 4x strings (of 18 cells each), where each string is protected by a bypass, hence any single cell would effect only its string. As with all things its just a trade off of cost and engineering, but with a less controlled physical environment on a boat it'll be fun!
So far in reading the comments, Mr. Morgan here is the only one who knows how a solar panel operates. I hope the Wynns decide to call a valid solar installer who is willing to explain this to them. The first question anyone qualified should be asking is, "What electrical load (in amp-hours) do you want to provide power for and how long?" After that, take a look at the most common voltage output you use on the boat and build the battery bank to hopefully match the most common voltage requirement. That way you minimize the voltage transforming to power your equipment/instruments. This plays directly into how you string your panels. It's fine that the Wynns are focusing on the electrical production, but how you consume also plays an important role in efficiency. Another important point, the engine battery should not be the solar batteries. There are a number of youtube videos that can be your guide on this.
in another blog, a yacht just installed two of the newer LG 340 watt panels it will be interested to see how they work out mounted flat on a yacht from a performance perspective.
That explains it all. Still, as an electrical engineer I can't for the life of me figure out why solar panel cells are strung in series. In parallel, they wouldn't need bypass diodes. I can only assume there is some MAJOR drawback with parallel cells, because if not, the series design is fundamentally flawed.
As for only some cells having a bypass diode, I guess its a case of "You get what you pay for", meaning more expensive panels will have more redundancy, but it is clear that manufacturers are not up-front enough about this specification. The redundancy spec should be as important as the max capacity of the panel.
+Adippen each cell still only generates a small voltage (
Aaah yes of course, that makes sense. Individual cells generate a tiny voltage, so you need a minimum number of them in series to output a decent voltage. Then you can connect those groups in parallel and/or, have a bypass diode per group I assume. Thanks for the clarification!
Excellent test - well done. I knew you guys would spin this sailing thing differently than anyone I've seen so far. Great job! I learned something. Thank you.
I did both series and parallel wiring for my solar panels on my bug out van and parallel was much better. Thanks for the testing video.
guys, love the channel, i learnt this the other day, you used two different types of panel the first ones were called monocrystalline, the work best in dierct sun light, the last ones were call polycrystalline and work better in any light. for my boat i will be using polycrystalline
Great episode! It wasn't what I was expecting either; but testing always shows the truth.Those shaded cells are acting like a load; and I thought the diodes where supposed to help stop that.
In a boating environment; or any environment where shading cannot be managed; you will want to look to Amorphous panels. Also called thin cell panels. These panels use cells that are very narrow but span the entire length of the panel. Although they don't produce as much power per panel; in your environment you will get more power throughout the day. Love you guys and best of luck!!!!
Good video. I have my 4 panels in parallel on my 50 foot boat. I have 1,200w (36 amps) and the winter sun angle makes the most shadows where I only get 15 to 18 amps no matter what we do !!
I used to have a little trailer, I don't know anything about solar (the boyfriend did all that) except how exciting it was when we had full power from our panels.😊 love you guys
Looks like a no brainer to go parallel - shading has a much bigger impact on serial set up. Consistent with what the yacht literature suggests! In any case we've just decided to skip the flexible panels on the bimini and see how we go with a hydrogenerator like Watt & Sea. We'll have portable panels for redundancy.
Guy who just crossed the Pacific to Port Vila swore by his hydrogenerator, it produced enough power to handle all requirements on his 40' yacht.
Do you have a link?
For the parallel vs serial set up in the yacht literature? No, it was in one of the main UK yachting press a few years ago. For the hydrogenerator: www.wattandsea.com/en
A very well done test in my opinion. That pesky boom is the real killer in mounted panels. No one says the panels have to be mounted. Put edge guides that will hold the panel in place but also allow it to be moved a few feet. The panels won't hurt a thing if place in the walkway along the sides of the boat temporarily. You guys will figure it out. Could also put a wind turbine at the very top of the mast. It's A.C. volts so just a small wire would be needed to the bridge rectifier then to the charge controller. A small 400-600 watt is better that none.. Thanks for sharing your test.
I loved the way you show the results, it certainly makes it clear how panels work for those who are not aware of electronics/DC electrical power systems. Just think of each panel as a battery (that only works when light is shining on i), and each one of the cells in a panel is also a battery. The cells in a panel are connected in series. Otherwise you would not get enough voltage.
Interesting test and an excellent demonstration on how critical it is to locate your panels without any shading. I see flat mounted solar panels all the time on RVs that are located next to AC units, antennas, etc. etc. and are shaded for hours of the day. Especially important in the Winter when the sun is so low on the horizon to have the ability to tilt.
I have 2 Kyocera panels a 50 watt and a 140 watt and they are excellent panels. At twice the cost at $2 a watt they are one of the most expensive panels on the market, so I'm not surprised the output was higher than your GoPower 160.
If you have the room you could mount a pair up front and a pair farther aft to minimize the boom shading at different times of day and direction. Or make 2 mounting areas and move the panels fore-aft as required. I run my 6 panels portable and have zero problems moving them around connecting/disconnecting daily.
I haven't removed the bottom cover of a solar panel to see if adding diodes to each cell is possible, but diodes wouldn't be a big added expense if there is enough room. Surely some company makes such a panel.....
I expect you will also be adding one of the newer windmills for charging at night and cloudy days. You guys sure do make your videos interesting and fun......thank you!
Just wanted to say that your hair color is simply stunning in bright sunlight Nikki.
If you want to know more you really should click over to our website, we provide links and additional info there. Below I'll try to answer some of the more common questions:
We're not Experts - As we always say we're not experts and by no means are our tests perfect. We have a question and we try to find a solution. That is it.
Diodes - Our panels have 3 diodes however I've been told when you knock out an entire cell it is common to lose the entire panel.
Wind & Water Generators - We are considering adding a wind generator and/or a water generator. Both seem to be viable options however we've been told solar is the first step for boats...and considering we already own the setup from our RV we think it's a logical place to start as well.
Hat - No we are not sponsored by John Deere, I've had this hat for over 10 years and with the intense FL sun I'll likely be wearing glasses and hats in every video. I will try to find an unbranded hat I like soon.
Thanks for watching and commenting, we love seeing the discussion, the questions and of course the experts chiming in with real solutions.
Kent is the man! Doesn't compute! The percentage of panel covered does not equal the percentage of loss of charge.
Amazing guys! I have a Rialta with minimal roof space and consequently circled the air conditioner with 4 x 100W flexible panels and have never seen great results. Granted they're wired in series. After seeing your video I'm contemplating rewiring! I may go with series parallel or all parallel. Either way, I'm amazed at how one cell knocked out the entire {array} when wired in series. I always thought series was the way to go but apparently not! Thank you so much for the excellent video that demonstrates this! I realized what the term array meant from your tilting video when the power didn't start flowing in at a higher rate until the last panel was tilted because the charge controller treats all the panels as a single large panel, or in other words, an array. Power comes from the least common denominator.
WOW....this is new to me....it looks like if the cell isn't producing, it becomes a resistor. They need to put switches that monitor and bypass the cells that are drawing on the system. Maybe a wind or hydro system would be more beneficial in this situation. Either way, I am really enjoying your channel.....Can't wait to get down in the Bahamas...Love Houston, but so sick of this Texas heat!
You were seeing what's called "cloud edge effect" at around 8:40 where a cloud somehow briefly focuses the sun for a burst of power. In fact, you have to account for this when buying a charge controller, making sure it has some headroom to handle the extra amperage.
You should be charging Kent for all the exposure he is getting. It shows that he cares about his clients. As far as the solar panels go that was very informative. It touched on matters that everyone talks about but only in theory, real life seems much different.
I ran across the following in an article about using solar for powering amateur radios, and thought it might be relevant to your issue with shading. "When selecting a solar panel, the key feature is a 'bypass diode'. Without that, anything that shields a spot on the panel makes that part of the panel perform like a resistor. Resistors have lower voltage. Silicon cells are supposed to produce voltage. Pretty quick, your efficiency is destroyed by random shading without the bypass diode feature. Of course, I learned that after making a purchase or two. Ready, fire, aim! All the major lessons of life are seared into your memory by shame, grief, pain, or all of the above."
Yep, our panels have 3 bypass diodes and they still get knocked out when a complete cell is covered.
If you guys haven't found them there's a solar channel called AltE on youtube. I've gotten some really in depth technical advice on that channel and from the channel operator in reply to my questions. They answered the series vs. parallel on their channel as well as what charge controller to use when you do one or the other. Might be a little late for you but you can't make a mistake testing it for yourself.
You have a very big Yacht. I would go with more then two panels and get a wind turbine. You can even get a thing to drag in the water behind you. I forget what it is called. Love you both! Happy sailing.
We just used two panels for the test. We have more than that for the install. We gave more details in the post: www.gonewiththewynns.com/Sailboat-Solar-Series-Parallel-Shading
How many? So much? wp.streetwise.co/wp-content/uploads//2013/06//boat-inno.jpg
Just kidding :-)
In the process of putting up our solar panels now and its a huge learning curve as it is totally new to us. Thanks for the great information!
I'm not surprised by the results.
It shows the concept of parallel and serie pretty clearly.
What a great demonstration.Very useful.
The other useful and easy thing is to show the single panel, one cell shading scenario too, to help verify the characteristics of the panels bypass diode setup. Low voltage panels are often internally a combination of series and parallel wiring of individual cell groups, so this might contribute to the partial shade characteristics. Different brands might matter - they are optimising for total output under uniform shade, and bypass is mostly about panel protection.
For pure serial connected cells, each group of cells covered by a bypass diode should reduce output in proportion as a group is taken out by shade. I don’t know why you didn’t see this? Worth investigating
For parallel connected panels, a bypassed group in one panel will rapidly push the panel into a very low efficiency zone, effectively reducing it's contribution to zero - exactly what you saw. Parallel panels really need chargers that accept their connections individually (multi string inputs)
I’d be really keen to see you play with a single panel, and show us how it behaves, and to compare higher voltage panels with that. I think that you might find that higher voltage panels will degrade more linearly, as they have no parallel component internally, and building a system of them might work better in partial shade? Also, knowing how the panel is laid out internally might help you decide it's orientation too (the paper below shows a scenario where shading just one row takes out the whole panel).
This might help too www.sicleanenergy.com.au/wp-content/uploads/2014/05/Shade-Effect-Paper_Final.pdf
Hi Guys. You need to go with higher amp panels to give you enough power. On my Leopard 40 I have built a frame for behind the boom sticking out a bit from the Bimini. I put 2 x 345 w panels up there in parallel with 2 controllers for redundancy. On the hook as my boat is stationary in one position I pull the boom to one side allowing max sun on the panels. I have 600amh of battery power. Using all the toys from sunset to sunrise with the fridge 24/7 I tend to use 150 amps. This is replaced on a normal day by 12:00 the next day. 400watts on a big cat is not going to help much ! Got a nice pic of my frame up if you want it.
Great vids
very informative, thanks for doing this test and showing how solar panels work when they are shaded when wired in series vs. parallel
As you found out, a solar panel is like a string of Christmas lights. Each panel is made up of a number and type of solar cell. Each cell is wired in series. So when you block one cell the 'string' fails just like many Christmas light strings. Your readings on the charge controller showed 1/2 power during parallel test because really only one panel was producing power. Sooooo since you have the panels from the RV, if you install them on different surfaces around the boat and wire them in parallel you will be less susceptible to loosing lots of power during shading of one panel. That outdoor prewire MC4 connector that you got Fleetwood to do on the RV would be a good addition to have on the boat. If the connector was wired in parallel with your installed panels, then you could add your portable tilting panel kit and aim them when needed.
Thanks. I had no idea that just shading a couple of cells could have such an effect. I was about to buy a flexible unit and mount it on the coachroof under the boom thinking that a bit of shadow wouldn't hurt. Time for a rethink...
yep, I keep thinking there must be a way to float a few panels behind us, that would be way out of the way from shading while at anchor :)
I think you guys are doing cutting edge work that gets into the public domain. Solar companies must be doing this basic research too but not putting it out there. Your results surprised me.
Hey guys, Just started following. I'm sure by now you have figured out that shading is the biggest enemy of solar. I've been in it for over ten years now. your test with shading was good but to help you understand the principle of what you were looking at the circuitry of the modules is to protect the module. Which means if you shade one it shuts down the module. Also, you need to keep them clean. Which means the salt residue from the spray would have diminished the performance. i think all in all on a boat go with a wind generator.
I don't think wind is the solution either...
To avoid this kind of loss you might want to look at Enphase micro inverters. They will allow each panel to act independently. Not sure if it will work for your situation though. Good luck and great show!
This video needs to be added to your solar playlist please
+Stim Racing Trailer and Travels good catch.
If you have the real estate (area) you will always yield more power into your batteries with amorphous solar panels. They are also more heat and shade tolerant.
In a real world test you should have some load in the circuit (like a light bulb) and be measuring power (in watts), which is the product of voltage and current together. Then compare the readings of parallel vs series connections, and your various blocking patterns. Also, since you got essentially similar results using different panel makers, perhaps trying different charge controllers might reveal an indicative result. Anyway, those were my curiosities from your tests. Overall, nice work guys! This is how we learn!!
The load is the battery. Which has a resting voltage lower than the one at the end of the charge controller so current flows to it... It is a real world testing, the panel/charge controller doesn't care if it's a light bulb or any other load.
I know there are still lots of questions to be answered based on this unofficial test. If you want to know a little more about the test, our experience, thoughts and the products we're using click over to our site...there's always more info there: bit.ly/solar-test
Thanks for watching!!!!
I was surprised to see that the by-pass diodes didn't work. That might be due to a MPPT algorithm that's not aggressive enough. Many modern MPPT's have a special more aggressive algorithm for when there's shading involved (e.g. OptiTrac from SMA). So maybe see if Outback has an firmware update or if it can be activated through settings. If the MPPT is able to find the MPP reliable it might very well turn out that series is slightly better, but for now you're conclusion is probably right.
Also if you want to learn a lot about solar, MPP, by-pass diodes, etc:
www.pveducation.org/
You lost me my friend. I don't understand how a diode which blocks traffic to only one direction and an algorithm go hand in hand. We are talking about two separate components here that don't talk to each other at all. The controller can only take what the panels gives it and then through the algorithm decide how to do it's output to the batteries. I took a quick look at the link you gave and it didn't help.
You're anthropomorphising to much, obviously they don't talk.
Also, you don't read enough. I'll take you a couple days at least to study that resource. I did say that you can learn a lot right?
Anyway, if that's more than your attention span, you might've read chapter 7.2, especially this page:
www.pveducation.org/pvcdrom/modules/bypass-diodes
"A bypass diode is connected in parallel, but with opposite polarity, to a solar cell as shown below. Under normal operation, each solar cell will be forward biased and therefore the bypass diode will be reverse biased and will effectively be an open circuit. However, if a solar cell is reverse biased due to a mismatch in short-circuit current between several series connected cells, then the bypass diode conducts, thereby allowing the current from the good solar cells to flow in the external circuit rather than forward biasing each good cell. The maximum reverse bias across the poor cell is reduced to about a single diode drop, thus limiting the current and preventing hot-spot heating."
I'll leave it as homework to you to figure out why might need a different MPPT algorithm to take advantage of such a configuration.
Paul
Thanks Paul that does make a little sense to me.
LOVE the John Deere Hat Jason!!!! A solar test is a GREAT idea!! Praying that solar works well on your new boat!!! Thanks for the GREAT video!!!! :)
Might be worth mentioning you should be measuring Watts not Amps. Watts are a measure of power Volts X Amps. Amps are a measure of volume of flow . In series you will have twice the voltage so even if you have half the amps you have the same power. If you got about the same amps in series you were getting twice the power. Your installers should have know that.
Parallel is going to be your best bet if multiple panels can be in shade. Wind turbines make a good complement to solar. It is a different animal and often works well on boats. You can also consider strings of panels (2 panels in series for example) with the strings in parallel.
best solar demo I have seen thanks for sharing can't wait till your out sailing on your own.
finally someone did those tests properly, nice work guys! decent information and conclusions, gave me the insight I needed
Between your demonstration and some of the comments, this has been very enlightening thank you for a great video. s/v Spokojny
Consider the option of two charge controllers in parallel, one for each panel. You will still get the loss on the shaded panel, but you will get full amperage out of the sunny panel. the amperage sums, voltage stays the same. some controllers have a dual mode for this purpose.
Before I watched this video I knew that series was much more affected by shade than a parallel setup. Still crazy to think though that even with parallel that a little bit of shade can knock out basically a whole panel. Hopefully we are able to come up with a working solution to this in the near future.
Excellent !!!, I would never have guessed that shading would have been such a big deal..
Great video! Timely as well, since we are just preparing to put solar on the C-Shel for our Bahamas trip in the Fall. Thanks so much. Parallel it is for us.
The wife & I love your video's especially now you are on the water. Keep them coming please.
We just had 2 x 200 watt flexible sunpower panels sewn in to our bimini on our 32 foot cruiser.
Panels are in parallel as are our house batteries. Winter here in Australia so can't run tests just yet.
But sunpower panels are the most efficient there is & I look forward to wringing every last amp out of them.
Good luck on your adventures. Enjoy!!!!!!!
I knew shading could be a problem, but had no idea one shaded square could kill a whole panel or series of panels. It is great to see a real world and well executed test!
P.S. I imagine the clamp meter you had is designed to only measure AC current. Since the panels output DC current, I expect that meter was not reading correctly and just picking up noise. But I noticed you didn't show any of the clamp meter readings in your video, so perhaps you already figured that out.
Installing Solar panel in series is used to take advantage of long cable runs so smaller wire (Cheaper), Long runs in Parallel would mean higher currents and maybe 2 times larger cables. Most panel do not have a shunt diode near near the outside edges where all the individual cells are combined. Series is most command in Home installations where there will all ways be a some distant on the install back to the charge controller.
Your finding are exactly what should be expected..
I have learned something today, thank you very much, still planning on a video on wind turbines?
If you have the real estate for large panels, use amorphous silicon thin film panels in parallel. They aren't as efficient but far more shade tolerant.
I can't wait until you guys start sailing.. oh what an adventure that i can be a part of. Thank you!
Great video and fantastic comments everyone!
Thanks again,
John H.
B.C. Canada
Also, If you guys will be doing any further tests, its important that you use the systems Wattage(or KwH, as the display will sometimes have it shown as) to gage the effects of shading. This is your total power. The amperage is just on of the two components that make up the power and when comparing series to parallel, you need the neutral component to accurately tell whats going on.
Yes, the amperage dropped off significantly when in series but the voltage is twice the amount as it is in parallel(when using two panels). So, your overall power most likely was not too different between the two tests. I have had the opportunity to be involved in similar tests with a case study we have going at UC Riverside. The whole thing was put together to test the claims of the Jinko modules i mentioned in my previous comment.
When comparing series vs parallel, the real considerations lie in the other components you plan to use with your system. It is almost always more cost effective and efficient to go series if you are using more then one module. You have less voltage drop, you can use smaller/less expensive wire, that smaller wire gives you flexibility with your run, you get more dependable/longer charging each day, and you can use smaller fuses/breakers to protect your system.
I hope you guys find what works for you. If you have any questions, feel free to HMU via PM.
Just a big "hello" from Sheffield, England. Looking fantastic!!!!! Thanks for sharing.
Since watching this video, I did some serious research on solar panels and found a company called SunPower. Their solar panels are designed for shade and harsh environments. They sound expensive but well worth it. Hope this helps.
They buy lots of expensive stuff - they can definitely afford the SunPower panels!
They are using all the panels they already bought, the 7 or 8 from their RV.
I caught that, they are the ones that don't like shade. Sunpower makes a solar panel that is designed for maximum output if in shade or even if a bird craps on it. Even on cloudy days, they out perform most others.
There will never be a situation where one cell is completely blocked from light during the day. Putting the cardboard over one cell is not a true indication of how the panels will work. But the video was very interesting and some good information. It does go to show that if one panel goes out you will have problems with your system.
What it showed was that if one or more cells are shaded then that panel is going to produce almost nothing. Having the second panel was masking the effect the shading was having on the single panel. One panel was producing full output whilst the other was dropping to almost nothing. What it showed me was that a small shadow across both panels was very bad compared to the same amount of shading to one panel. So for a boat where shading radiates from the mast it would be better to have a starboard and a port panel layout versus a bow and stern type layout. So that there was more chance of one of the panels being unshaded for longer.
In case you didn't know, its because your cells are in series. If you had a whole bunch of little 10 watt panels, the resulting shading would be much less of an effect. When you shade a cell, you are essentially cutting off the flow of electricity through that panel.
Location of the panels needs to be looked at which I am sure you have considered, I have seen panels installed over the aft dingy which takes the boom and rigging out of the picture. Also agree the a wind turbine would help in this instance to supplement your power gathering needs.
PV panels are internally wired in series, usually into a single panel charge controller, then sent out via whatever type of connection to a bank. Because of the nature of semiconductive chips, when you fully disable a cell it effectively increases the resistence that energy being produced in surrounding cells must pass through in order to exit the panel. This is also why multiple panels in parallel is more efficient, so that when only a single panel is at a higher resistence, it isnt affecting the entire array. The only practical way to elimate cascade resistence from shading is to custom build your own panels, wiring the entire panel in parallel, a step that means little to 99% of solar users. If it were me, I would build a bracket above your dinghy davits and run 4-5 kyocera panels in full sun, rather than a much larger partially shaded array. Good luck guys. ~J
Wow, what an interesting test. You guys are truly innovators and I enjoy all of your videos and comments. Thanks
Charlie and Martha (Wandering Toes)
OK I love your commitment to solar. So new appliances for the boat. The refrigerator is an energy hog. Much better choices but I do not know how sea tested they are.
That answers my FB question if tilting will work on a (your) boat 😃
You were quite series-us about your parallel testing. I got a charge out of it, at least until the boom hit and I could not amp it up.
Makes sense because the cells in the panels are wired in series so when you take one cell out you break the circuit which takes out the whole panel. I've heard the older poly panels do better with shade and they are cheaper too! Never tested them though :/
I also thought the bypass diodes were to mitigate the power loss from shade so I was surprised by your results... I went googling and ended up finding an interesting document that explains that the diodes are actually to protect the shaded cells from being burnt up by the unshaded ones in the same string of cells.
Learn something every day!
Here's the doc if anyone is interested:
www.solaredge.com/sites/default/files/se_technical_bypass_diode_effect_in_shading.pdf
Great video from your usual average person viewpoint!
surely the solution is like what is on Impi cat channel?
Tube structure built over dinghy davits !
Due to the wide beam of your monster I can see how tilting could be incorporated as well.
Brent on Impi also talks about having a "weather guy" so I think that is something to look into as well.
Have loved your transition from 4 wheels to 2 hulls and really looking forward to the ongoing !
Look after one another !
altE did a video on using a different chg controller for different panels which will keep one shaded panel from dragging the other one down. One example given was on a sailboat application.
I know this is an old video, but it was *very* helpful.
We love to hear that! Keeps us motivated to make more. Thanks for being a part of the crew. 😘💙💙
THANK YOU! for actually testing. Sooo many videos saying this and that will and wont happen but no actual testing. So thank you and I'm subscribing.
This was a really interesting experiment, and hopefully this information will be of use to you. And I hope Nikki's hand is better!
Many people mount their panels on an arch over the dingy davits to avoid shading. Some people mount their on the life lines and pull them up when needed.
The series parallel test is basic high school math
Parallel is positive to positive and negative to negative , voltage stays the same , amps are added together
Series is negative to positive, Amps stay the same , voltages are added together
On our catamaran we are mounting above the dingy davits but the boom is still a factor and will still create shading.
There are all kinds of options but $$$$
But it's easier and cheaper just to live with it, watch your consumption, get more or better panels at a future date, they are becoming cheaper every year. If your boat don't have a generator, get a Honda 2000 for topping up under heavy use
The reason the drop is always ~50% is this:
A solar panel with 72 cells is actually two sets of 36 cells wired in series, then the two series are connected in parallel. So if you shade one cell, effectively that entire series is shorted out so you're only getting power from the other series that's un-shaded.
Think of the old school Christmas lights where when one bulb goes out the entire strand goes out. So, in a solar panel you basically have two strands of Christmas lights each with 36 bulbs, and they both sets of lights are twisted together. If one of the bulbs goes out (is shaded), then half your lights go out.
So, the question is - why would they connect the cells in a series instead of parallel? Each cell produces about .5V of power. If you connect them in a series, the voltage multiplies time the number of cells connected. If you connect in parallel, the voltage stays the same. (Regardless of connection, the amperage increases). So, in perfect conditions:
30 cells x .5V = 15V (the voltage to charge a battery needs to be slightly higher than the battery voltage, so a 12V batter needs a ~15V charger.)
A 60 cell solar panel will have 60 cells, but they'll have to be divided into 2 series of 30cells to get you the 15V. Each of the series combines parallel at the end to give you twice the amps (but still 15V).
15V is the minimum voltage required for this type of use. You could have a panel where all the cells were in series which would give you 30 V and then use an inverter to step it down to 12V (with no theoretical power loss), but that would mean if any of the cells were shaded you would have a complete power outage from the panel.
The ideal set up (currently) would be to have a 72 cell solar panel then use an inverter to break down the power into 12V and 24V for the two systems, but the 72 cell panels are considerably more expensive.
Ultimately though, on a sailboat the panels themselves definitely need to be wired in parallel (as you've demonstrated).
You guys rock! This is great stuff. REALLY useful to cruising sailors. Thank you so much.
Loved the video, had no idea that a little shade would have that much affect
That was really interesting and useful. I'm now running out to do the same shading tests on my panels ;-)
Some Cats put solar panels over the davits, if you did that you could design a mount that would let you tilt the panels to improve the angle. You could also have a couple of panels that are stored underway but that mount to the rail an could pivot, even be height adjustable to keep them from being shaded. Many boats also have wind generation mounted which will give you power from the gentle tropical night breeze, or gale as the case may be. Just check a bunch out first some are loud.
Your results are typical with the types of panels which you were using for your test. This is also one of the main issues which solar panel manufacturers face. You may want to check out TenK Solar, their panels do not have the shade issues which you have shown. I know because I have their panels installed on my house, which has a tree which shades a number of my panels, but I still get decent power out if them, even when more than 1/2 of the cells are shaded. I am planning on using a panel or two for my RV, since I expect to have tree shading issues while parked.
Good and realistic solar testing, and some fun. Thanks a lot.
just saw your new episode, it was great one. Probably you will need to install one or two wind turbines as well i heard Silentwind Generator is quite good and very quiet
Those crazy PN junctions and their quiescent point!
Great video and sail in good health! Looking forward to the onsite update as well as daily amp inputs...
If you mount the panels over the dingi they will be clear of the boom shading and give some shade to reduce sun bleaching to dingi.
Many places mention this lose from shadowing. It's not proportional to the area of the panel, although people on UA-cam disagree in the comments. The second panels are more efficient. Gopower panels have a lower efficiency. Wattage matters but only when comparing to two panels at the same efficiency.
Intersting video. My first thought is to add as much panel as possible and use a charge controller that can accept any amount of power even if it can't process it into charging. Also I am curious as to the possibility of wind power on a sailboat. Interested to see how things work out!
Look into having a rack built over your Davit to avoid any shadows
Hey guys,
Love your channel. I would suggest you look into a module called the Jinko M-series. They come in 260 watt modules and would be perfect for your application. They have led the market in the last year in cell string level shade mitigation(they call it Cell String Power Optimization). The technology does the same thing that products like SolarEdge and Enphase do, except they bring it down to the cell string level, making them the best solution for shade mitigation available. The beauty of their product is that it is not proprietary so you can use it with any inverter/charger/battery setup. I have worked in the solar industry for a while now and was a little skeptical to hear some of the claims Jinko was making when our company brought their product on. I have since been proved wrong and am now a believer after personally tracking over 200 jobs installed with the jinko 260 watt pannel. Check 'em out. Not sure if you are in the market for something new, but IMO, when you are relying on Photovoltaics for electricity and space is an issue, the solution is efficiency.
Anyway, probably sounds like i work for these guy but I don't. If you don't go that route, i highly suggest you swap out those other module you have for a single Sunpower module or a pair of them if you've got the space.
file:///Users/admin/Downloads/SMART%20MODULE(maxim)%20(1).pdf
Internal Bypass Diodes may be responsible. Our Solar panels do not suffer from such high loss on shading - Our Solar Innova 155w (X3 panels) apparently have 6 diodes per panel. So with loss of one cell we should lose 1/6 amperage if controller is working well. How many diodes do your panels have?
Hello Guys. We have confirmed that our GoPower! panels have 3 diodes. I'm assuming the Kyocera panles are the same since they performed similarly. It's interesting to hear that you're panels have 6. I'll do some more research :)
I hope we can cross paths one day, you two are an inspiration to so many dreamers out there.
So This test also tells me that 4 smaller panels that cover the same space/wattage would do better in shade conditions than 2 high watt panels.
+Michael Zietlow we thought the same thing!
Here's a really good link explaining shunt diodes and how they help. And also have a look at Half-cut cells. www.thesolarnerd.com/blog/which-solar-panels-work-best-in-shade/
If using cheaper panels, (with fewer shunt diodes) you'd be better using several smaller panels wired in parallel, although this isn't as space efficient for the same overall power, but you might find that you generate more power with 6x100w independent panels than 2x400w panels in situations where you are likely to have partial shading.
If you decide to ad wind power, know that many units are loud and create vibration. Selection of the right turbine and mounting are critical.
If you are at anchor, you can always move your boom off to port or starboard, so it is not shading the panels----depending on where they are installed. Also, how are you enjoying the humidity here in South Florida???
Not sure exactly why I’m enjoying this series so much, considering I’ll never own a boat.
I think the problem is inside each pannel. Cells connects series inside. If i am right you just should sell this pannels and buy another.
It was intersting video. Thanks !
That is why we tested multiple panel brands. They each have diodes but they only do so much when it comes to shading an entire cell.
@@gonewiththewynns hmm, may be it will be right to made experimental personal one pannel fully paralel inside ? I think if you ask about this to manufacture they will answer, or you could ask this question to one of manufacturers from the AliExpress.
Any way if i'll found somth interesting about this topic on UA-cam i can put link here :) For me it was surprise too that so small shadow could shutdown the whole solar panel oO
As your old gopower panels are from the rv, perhaps the difference is actually on the glass itself. I'm going to guess there is micro-pitting and scratches that is diffusing the sunlight enough to make a fresh panel out perform it.
Really interesting. Thank you for sharing! ⛵️
It also depends on how many by-pass diodes the panels have, if any. Canadian Solar uses half-cut cells and has more columns. They put a by-pass diode on each column. Allegedly, Sunpower has a by-pass diode across each cell. I don't know about other panels... damn hard to find that info.
Interesting to see that fall-off in power. Re other sources of power. What kind of props do you have? ( folding, feathering, fixed pitch.) If you are running fixed pitch props you could add an extra pulley, belt and alternator on the prop shaft and take advantage of the flow of water passing the props. Also gives you triple redundancy in the event of an alternator failure. PS..... just checked your haul-out / survey video...looks like fixed pitch!..... worth considering.
Mind blown! Seems like numerous small panels wired in parallel would be more reliable than one large panel if there is ANY chance of shading.
Just so, I'm not any sort of knowledgeable as to solar panel construction, but it seems that the sections of each panel is wired in series and that there is no pass through of the electricity generated by the separate sections if one entire section is covered and there is NO electricity generated from it.
I would not have believed that would be the case. I wonder if there are Marine solar panels that are wired in parallel to avoid this
Less wiring maybe? Like the old strings of Christmas lights.
Mike Siedlecki Probably exactly right, less wiring. I suppose it makes sense for most applications where solar panels are installed, Doesn't work exactly right for a sailboat though!
no...it's like hooking up batteries. do you need voltage...or current? then connect accordingly.