Flexible solar panels: how NOT to buy them for your Alto

From the moment we put the deposit down on our Safari Condo Alto F1743 trailer I planned to cover the roof with solar panels and install lithium ion batteries so that I would not have to burn any propane to heat the trailer or cook meals. I wanted to go 100% electric. That’s extremely unusual in the RV camping world, where running gas-powered generators and  using propane is the norm. But after almost four years of driving only electric cars there was no way I was going to go back to fossil fuels.

The Safari Condo solar options were puny

The solar options offered by Safari Condo were inadequate to achieve my goal; either 100W or 200W of flexible panels on the roof and no high capacity battery (note: in 2020 they changed to offering either 220W or 440W). With zero practical experience installing solar panels and all the associated hardware I did not want to attempt the installation myself. Fortunately, a web search revealed a company not far from me, Quality RV Solar and looking through the project portfolio quickly convinced me I had to go talk to them. Located in Fremont, California, not far from the Tesla factory, I immediately warmed to owner Dan Reshatoff. We discussed my goals and over the next several months finalized on a plan for the maximum possible solar panels on the Alto roof and two 300Ah LiFePO batteries.

Although Dan had not used flexible solar panels before, he had done many rigid panel installations on RV roofs. I volunteered to source the flexible solar panels and purchase them directly, and he would procure all the other necessary hardware.

My first thought was to buy the panels direct from Sunpower, as they offered very high efficiency flexible panels and had a reputation for quality. Plus, I had a good friend high up in management there! 🙂 Unfortunately, I soon learned that Sunpower had discontinued US sales of their 110W panels and the only size they offered was 100W. The dimensions of the Alto meant that I could get a maximum of maybe 6 panels on the roof and there would be a lot of unused space. I wanted more…

And then I found Elfeland panels

A web search revealed that a Chinese manufacturer produced a wide range of flexible panel sizes under the name “Elfeland”, and serveral resellers sold them on eBay. An Israeli company, AlexNLD, also sold the panels but their prices were significantly higher.

So after developing a list of all the available Elfeland 18V panel sizes and carefully measuring the Alto roof dimensions to figure out the different sizes I need to cover as much roof area as possible, I started ordering panels from several ebay sellers. What could go wrong?

Answer: EVERYTHING. Do not buy flexible solar panels on eBay from Chinese resellers. Here’s what happened:

  • I got panels that were a significantly different size from the dimensions shown on the ebay product page. The seller, anglestore, blamed a “unit conversion error” and didn’t want to take them back.
  • But the panels were also not the advertised voltage, which was 18V, they were 48V! The seller said they would give me a $25 so I could buy a “transformer” and use them. Unacceptable. I used the eBay complaint process and was able to return the panels for a full refund, less shipping.,
  • A panel purchased from seller greatoutdoor arrived with two large holes in it. See the photo below. They had packed up a severely damaged panel and shipped it to me. Who would accept that? Not me. It was returned for a full refund, less shipping.
  • Ordered the same size panel from another seller, mhestore2009, and it arrived damaged with signs of fracturing in some of the solar cells. Also returned for a full refund after going through the eBay complaint process.

In each instance the seller resisted my request to return the panels and came up with absurd excuses and reasons why I really should be able to use them. It was almost comical, except that it was really just incredibly aggravating. It also delayed the completion of the solar installation by several months. Dan was very patient and worked around the delays.

Ultimately I got the panels I wanted in the sizes I needed, through eBay seller ouyou2010 and through AlexNLD. My recommendation is to only use AlexNLD. You will pay more but I think you will get better customer service and no problems. Here are the panels I used and their dimensions in inches:

  • 20W 16.5×11
  • 35W 16.1×20.1 (two panels)
  • 40W 33×11.2
  • 140W 46.5×21.25
  • 200W 57×31.14 (four panels)

With those panels I was able to completely cover the available roof space I had to work with, allowing for the central vent fan (standard on the Alto), the small plumbing vent pipe on the port side by the roof edge, and few other items that Quality RV Solar installed at my request.

Next: details of the 1035W solar and 600Ah battery installation using an Vectron MPPT charge controller and Vectron 3000W inverter.

Some of these panels fit so well into the available space it looks like they were custom made. They were not. Serendipity. (NOTE: see update below this photo)

1369F238-CB18-4758-9593-543F478E1513

Update: panel failures and replacement

Some of the panels I installed in 2018 failed during the summer of 2020, probably because I did several camping trips in Northern California during the summer when temperatures were in the upper 90’s for days in a row, and the panel temperatures were likely over 110 on a daily basis.

In early 2021 I replaced all the solar panels with a much higher quality panel, the Solara Power-M. See  https://www.emarineinc.com/SOLARA-Power-M-Series (that is the company I have purchased from). Here is the data sheet https://www.emarineinc.com/Shared/pdf/Solara/SOLARA_POWER_M_series.pdf

Those panels have external cell protectors with bypass diodes to protect against cell overheating, a feature which the Elfeland panels lack. They are also much sturdier (you can even walk on them) and the cells are better protected. That makes them less flexible and I could not place them quite as far aft as I would have liked. Fewer size choices meant I had more gaps between panels.

Unsurprisingly, they are also much more expensive. So far they are doing fine. They are slightly more efficient and their output on a hot day does not drop off as much, so even though their total max rated output is significantly less than what I had before, in reality they produce more energy than the panels they replaced.

16 thoughts on “Flexible solar panels: how NOT to buy them for your Alto

  1. Pingback: For Alto enthusiasts: factory options I recommend | Electric Travels

  2. Pingback: Camping 100% electric = no propane | Electric Travels

  3. It appears to me that the Alto roof has fewer factory items on it than the Airstream roof, which has an AC unit (or units?) and multiple vents. I spent hours researching the many sizes of Elfeland flexible panels and working out how they would fit together on my trailer roof. Here’s a list of the available 18V sizes that I did NOT use:

    Elfeland 50W 21×21
    Elfeland 80W 34.6×21.25
    Elfeland 100W 41.3×21.25
    Elfeland 250W 62×36.2

    With so many sizes to chose from it was possible to design a layout that came pretty close to covering all the available area on my trailer roof.

    With so many choices, I think you could get well over 400W of panels on your Airstream if you switched to Elfeland flexible solar panels.

    That said, the flexible panels may not last as long as the rigid panels. So that is a potential trade off. And replacing one of my flexible panels would not be easy given how tightly bonded they are to my roof with the 3M VHB tape.

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  4. Based on your photo, I think that using a variety of flexible panel sizes that you could increase your total panel output by as much as 50%.

    But the difference between us is that my goal was 100% electric, no propane. For that I needed to maximize the solar output on my relatively small trailer roof. So that’s what I did. You are still burning propane so whether you have 400W or 600W of solar on your roof you will still be burning some propane.

    That said, if I’m at a camping location where it’s really cold and cloudy I would likely not have enough electrical power. Fortunately for me I don’t have an interest in those camping locations. 🙂

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  5. Hi Barry

    Thank you for all of the information. What are your thoughts on the R version vs the F version for optimizing solar output and general construction. We are going to get a Safari but like you were, I am in the planning phase. We are in Northern Ontario and will definitely be using the trailer into the late Fall.

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    • Hi Robin,

      Good to hear from you, sorry for the delay in responding but we were away camping and offline for several days. Regarding your questions, I think the available roof area of the R Alto model is about the same as the F1743 so you should be able to get about the same amount of solar power generation in both. Of course the F2114 model has much greater roof area since it is four feet longer. But it’s a trade off as always; smaller trailers can fit into campsites that larger trailers cannot, and larger trailers have more room inside and bigger tanks. We are very happy with our F1743, it’s enough space for us though it would certainly be nice to have larger tanks and a bigger refrigerator! As to the “general construction”, the R and F Altos are made of the same materials and I’m sure made to the same level of quality. I discuss the differences in my post at https://electrictravels.blog/2018/09/05/a-safari-condo-is-not-an-apartment-in-the-serengeti/ under the subhead “Why I chose the fixed roof Alto”. Let me know what you decide!

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  6. Looks like it’s been a couple of years since you installed the solar power system. Have you upgraded anything? Are you happy with your system? Would you recommend the same system? I’m going to purchase the same Alto Condo 1723 in 2 years. Please let me know what you think! Thanks.

    -Danny

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  7. Hi Danny; I’m going to update the post on this page soon because I am in the process of replacing all my solar panels with a much higher quality panel, the Solara Power-M. You can read about them here https://www.emarineinc.com/SOLARA-Power-M-Series (that is the company I have purchased from). Here is the data sheet https://www.emarineinc.com/Shared/pdf/Solara/SOLARA_POWER_M_series.pdf

    Those panels have external cell protectors with bypass diodes to protect against cell overheating, a feature which the Elfeland panels lack.

    Some of the panels I installed in 2018 failed last summer, probably because I did several camping trips in Northern California during the summer when temperatures were in the upper 90’s for days in a row, and the panel temperatures were likely over 110 on a daily basis.

    All the other components of my solar system have been working well and I am very pleased with it.

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  8. Anyone contemplating this sort of work on an SC trailer needs to consider the pros and cons of flexible versus rigid solar panels. The R-series and F1743 have curved roofs throughout, so only the flex panels make sense for those. This is unfortunate because it means those PV systems will only achieve their design performance in the tropics, since flex panels don’t do nearly as well with low solar angles. Also, rigid panels can be tilted if needed, adding another huge performance gain. Anywhere north of the southern tier of U.S. states, you really NEED this tilt from September to April. The fixed flex panels just won’t cut it during those months. In Canada during the winter you would actually do better by hanging the flex panels vertically on the SIDE of the trailer. So the R-series and F1743 will be lousy for boondocking during those months unless you use suitcase panels jacked into external ports added to the trailer. Yuck.

    With the larger F- and A-series trailers you can go with rigid instead of flex because they all have large flat areas on their roofs. If choosing an SC trailer with boondocking in mind, I’d go with one of those models and have SC just prep the trailer for aftermarket solar, giving me a blank canvas for my own system. Their factory solar kits are a step up from most but still blow compared to state of the art. Even Barry’s “maxxed out” PV system on the F1743 is pretty severely compromised by the curved roof and use of flex panels.

    The only hands-down “pro” with the flex panels is their aerodynamics. They also LOOK sleek and sexy for the fashion diva types.

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  9. Hello Puddin,

    Thank you for your message. I certainly agree that flexible panels have their drawbacks, and obviously in the winter months their output is minimal. But the Alto is a “3 season” trailer, it is not winterized, and personally I will never use it anywhere that has a “real” winter (I have posted about a trip to Joshua Tree NP in the winter and it actually snowed, but that was unusual).

    However please keep in mind that from my perspective — towing with an EV and needing to minimize range loss — fixed panels were not a viable choice as they would ruin the aerodynamics of the trailer.

    Best regards,

    Barry

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    • Dear Barry,
      I don’t mean to “challenge” your decisions at all. I understand and respect them. As I said, flex panels are the way to go on the F1743 (although Zamp’s Obsidian 90W LONG panels, 11/16″ thick x 14.3″ wide x 59″ long, “shingled” to the roof’s curvature with Zamp’s low-profile mounts might surprise you a lot). I also thoroughly appreciate how you’ve shared your efforts via this website. No other SC owner has done anything like this, especially in writing. Your work has given me endless food for thought. I was very taken at first with SC’s solar design logic and how you had taken it even further. Your enhancements inside the trailer are still dreamy.

      But once I got interested I dived deeper and discovered other options and perspectives you hadn’t touched on, and I felt that others like myself reading your website should also have that exposure. To enrich the discussion, you see. Especially with the A-series or larger F-series trailers, which lend themselves better to rigid panels. I’m very interested in making the trailer as *capable* as possible for the off-season and high latitudes. The lack of real insulation makes these trailers unsuitable for winter, true, but that doesn’t rule out “snow-birding”– but even at the Salton Sea or Key West in December, you’re still going to NEED to tilt those panels. The climate is mild enough but the solar angle is barely more than 40 degrees at “high noon.” And the tilt will be just as needed when touring Canada or Alaska even in June. Or Montana or New England in September. Having rigid panels that can tilt expands the possibilities and amp-hours a whole lot throughout the year.

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  10. Thanks for the heads up about the Zamp Obsidian panels. I found a spec sheet on them here https://www.specialized.net/amfile/file/download/file/5124/product/16801/ . For an RV with a flat roof they are certainly an option. The spec sheet does not state that they include bypass diodes to manage cell overheating, which is a desirable feature.

    Regarding the need to tilt solar panels, that is certainly desirable and will of course increase panel output. That is what is done on fixed structures to optimize energy production. But because an RV is by its very nature a mobile vehicle, installing angled panels is counterproductive in my opinion. They will often not be at the correct angle relative to the position of the sun since campsite spots generally do not allow the RV owner much flexibility in positioning their vehicle for optimal solar power generation. Given site constraints, tilted panels are as likely to be facing away from the sun as towards it. Keeping the panels flat is a compromise that works whichever direction the RV is positioned.

    If an RV is usually sited in a wide open area with lots of flexibility in positioning than I agree that mounting panels with a tilt optimized for latitude is the best choice, though trailer aerodynamics will be negatively impacted. But if the trailer is, for example, used in Canada in the summer and also in Arizona in the winter, the tilt angle will never be even close to optimal. Again, the problem is that an RV is mobile and a house with panels is not.

    Everything is a compromise. 🙂

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  11. Tilt-mounted panels are never left tilted up while the RV/trailer is in motion. That would be a sure way to damage the panels and/or wiring. They have to be stowed flat for driving then redeployed at the next campsite, all of which is done easily and quickly using AM Solar’s tilt bars

    on panels mounted using their rocker foot mounts

    I would make different choices for certain hardware bits, but you get the idea.
    Zamp Obsidian panels can do this too if mounted with Zamp’s “stabilized” mounts, which accept the same tilt bars

    You don’t have to go ON the roof, either. Just whip out one of those telescoping ladders, climb it until you’re hip-high against the roof, and lean across to do everything.
    Granted, this is more “fiddle-y” than fixed panels when moving between camps, but there’s a huge pay-off, too. It’s like using a stabilizer bar trailer hitch: big PITB factor when hitching and unhitching, but the ride quality and safety pay-off is so huge you might want to anyway. And you can forego tilting, too, and just leave the panels flat, but the tilt capability will be there WHEN you need it.

    Also– and this is another big game-changer for what you said– notice that there’s not one but TWO directions of tilt available, opposed 180 degrees to each other. This makes tilting toward the sun way more feasible than you’re thinking. You may not get a perfect due-south aim, but you can probably get close enough, especially if you have SC’s trailer mover option so you can skew the trailer in its parking spot once it’s unhitched.

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  12. Thanks for your comment, but getting out my 8 ft telescoping ladder to set up panels when I get to a campsite, and then getting it out again to make the panels flat before leaving the campsite is more effort than I care to put in. My current flush-mounted solar system meets my needs and takes zero effort. For trailers with a flat roof — meaning not mine — some owners may wish to go with tiltable panels, though on large RVs it will certainly be difficult to manipulate the tilt mechanism without getting on the roof. Personally, I’ve seen a lot of trailers with panels and have never seen the adjustable tilting type.

    I also don’t use a weight distribution hitch with stabilizer bars, not just because they are a pain to deal with when hitching/unhitching but because my trailer fully loaded weighs less than 50% of my tow vehicle, so they aren’t needed.

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