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StirCrazy's avatar
StirCrazy
Moderator
May 12, 2026

Time to start looking at solar.

so got up on the roof yesterday and measured everything up.  so what I end up with is basicly 4 spots I can put a solar panel.  

so drivers side front is 56" x 32" rear is 72" x 44" pasenger side front is 64" x 28" (there is an existing 100watt panel there right now) and the rear is 81" x 32" . 

so my delema is the panels I wanted to use were 320 watt panels but they are 64.6" x 34.7".  so the pasenger rear side starts to prevent a issue.  I could sneek another inch off of that side but that would still leave just over 1.5" sitting proud of the side of the camper.  would it hurt anything...  probably not. I am planing on putting a box awning on that side in the future anyways.  

so thoes panels are a 24V panel "N" type solar cell so more efficient and so on, and believe it or not a renogy branded panel.  do you know how hard it is to find a panel in that 200+ watt to 380 watt range, and how much more expensive they are than a 500- 600 watt panel.. oh man..  

anyways that setup would give me 640 watts with two panels.  

the other option is to go with a 195 watt panel by eco-worthy, I didn't know they were branding panels now, but hey.  these are a bifacial panel so if mounted right they would give you up to 220 watts, but I won't be mounting them right so what I should see is maybe 200 and some increased low light preformance.  but they are 52.6" x 26.4" and I could get 4 of them for about the same price as the renogy panels maybe 50 bucks cheeper but it will take more to mount them.  the big thing is I will end up with 780 official watts but up to 800+ in reality.  but they are a 12V panel.  now the open circuit voltage is only 23.7V so in theory I could run all 4 in series and have very high voltage coming into the solar controler or I could split them into a serries/paralel setup

so the big question, who hear is running a seup with smaller panels, how do you have them setup and how are they preforming?  

12 Replies

  • StirCrazy's avatar
    StirCrazy
    Moderator
    May 20, 2026

    so newest update, after a few days of searching for afordable panels on the internet 🙄 I finaly decided on THESE as they were semi afordable.  the other update is that after days and says of searching for panels I just couldnt find one that was under 28" to fit on the other side so instead of four panels I only got 3.  that still gives me 600 watts + what ever I gert from the bifacial.  doing a normal surface mount on a white roof they say its probably good for another 5% which I don't care at that point, but what did interest me is they are type N panels which are good, and that the bifacial provides a little kick over a regular panle in low light conditions,  besides it will give me twice what I had on the old camper.  

    another good thing about these panels is they are offered in 12V or 24V versions, so I got the 24V versions.  now I can run them in series and increase the charging efficiency.  

    big question time.  I am still going back and forth with renogy and victron, so I have a question for the victron users, are the lights on the unit ever on and or flashing at night?  I fear I might have to mount it on the wall in te bedroom, or extend wires so I am just trying to decide which would be sutable for a bedroom wall mount if I have to do it that way.  

  • Bedlam's avatar
    Bedlam
    Moderator
    May 13, 2026

    Panels in parallel have to have same voltage. Panels in series have to have the same wattage. Batteries in parallel have to have same voltage and wattage. Batteries in series have to have same wattage. Panels and batteries get confused as how to combine them.

    • StirCrazy's avatar
      StirCrazy
      Moderator
      May 14, 2026

      ya and its not even that easy.  everything I have been read and explained to me on solar forums and what not, points to it doesn't matter it if series or parallel the smallest panel will set the tone, in volatage for parallel, or amps in series. I have a basic understanding of why, but I do want to dive into it deeper as the understanding I have now is not enough to expain why to someone if they ask.  

      I personaly have never seen this as I have always went with a single panel or identical panels and I only found this out when I asked about it on a large solar forum as I knew the sides where I can put panels were different widths.  so basicly, if you have two different sized panels the way to go is two solar controlers, if you have three different size panels then 3 solar controlers, the batteries don't care what is sending them power, as long as its the right volatage.  

       

    • Camper_Jeff___K's avatar
      Camper_Jeff___K
      Navigator
      May 13, 2026

      Demonstration of Series and Parallel

      According to this guys demonstration, if you have different size or rated panels and voltage, you will get better results in Series. Also the larger the panels in an array, The greater effect an oddball lessor panel will have. If the panels have close to the same voltage, you're better off paralleling them together. Watts isn't a measure when combining panels. Watts output is the measured result you get when testing the result of whichever combination you use. Rule is, close voltage in Parallel, and close amperage in Series. Wattage is the final result measuring voltage out times amperage out = wattage produced. Yes, batteries you want to match to the same model as the existing units. Different size batteries will discharge from Larger to smaller batteries in the connection. You especially do not mix different battery types with different ambient voltages, Lead Acid 12.6, AGM 12.8, LI 13.2.

  • Camper_Jeff___K's avatar
    Camper_Jeff___K
    Navigator
    May 12, 2026

    I have 5 panels, all GOPOWER and one Zamp 115  watt.

    All are in paralell with 10 gauge uf resistant wire inside split loom. They are from different times, incremental installments. 

    180, 190, 200, 200, these 4 are the same size. Then I added the Zamp 115 watt more square than rectangle and it has the exact same specs as the others so it's a good match that fit a space. This year, I had another area on the roof that kept pestering me, so I installed another long narrow 100 watt GOPOWER. I have the Zamp 115 and GP 100 wired paralell with each other for combined 215 watts on a 10 gauge. The wires run down next to the sewer vent. Since the panel voltage is a more efficient higher 24 volts, I opted to run those wires down to the Victron 150/70 MPPT solar controller where it becomes battery voltage. From there, it's I think a 2 gauge cable to a Victron Distributer bus and either to the house or batteries as needed. 

    I opted for paralell wiring because in a partial shade condidion, you only loose 1 panel output instead of the whole series string. With 10 gauge wire on each paneloutputting 200 watts. About 15 amps max on a 30 amp rated wire, the line loss isn't significant. 

    I tried my best to find exact size, tight fitting panels and decided they didn't exist. What I did get were good quality, mono crystal panels that were a decent price. I do have most of the roof space covered and there is enough space for 1 more in the back, 1 in center right, and 20 across the front of the cabover. I could nearly double my solar filling those spaces but then, I'd have no roof access to service and maintain the camper. Another consideration is, I left space between the AC unit and panels to minimize a shadow being across a panel and loosing power. The tighest most efficient space fitting isn't always the best thing. Best wishes on your install.

    • StirCrazy's avatar
      StirCrazy
      Moderator
      May 13, 2026

      you do realize when you have different size panels they all act like the smaller panel on the controler, right?  I am trying to keep everything on one solar controler other wise I could go with two different size panels and get 1040 watts up there if I go with two controlers.  

      the issue is if you have say a 200 watt panels and a 300 watt panel on a single controler all you will get is 400 watts max.  this was my original plan untill I did the research and found this out, I didn't realize this would happen either.

      so for example I could put a 400 watt panel in the one side a 320 on the other, then two 200's up front.  All I would get is 800 watts instead of 1120 watts.  so if you put that zamp on the same controler you lost power not gained it.  but it sounds like you have the two small panels on their own controler.  another way to beat shading is to get panels with more busbars and diodes.  that way if a panel is partialy shaded you don't lose it all in any situation.  plus more busbars offer better performance in low light conditions.  I kinda want to do the series/parallel set up as I like the higher voltage, it makes charging more efficient and it starts a couple hours, in the morning,  before the 12V setup I have in the 5th wheel but thats not here nor their.  If I lose one side it will be no big deal because I am almost trippling what I had in the old camper and I never said, "I don't have enough panels on this"🤣 

      • Camper_Jeff___K's avatar
        Camper_Jeff___K
        Navigator
        May 13, 2026

        My understanding is the voltage match is what matters. The panels will work like the lowest voltage panel. If you have 4 panels, 2x200 and 2x300, You would be best wiring them in series parallel, 200+300 and 200+300 to create a series match of voltage and other characteristics. My panels run through the one 150/70 MPPT controller. The panels I have are all within millivolts of each other and work well together. I've seen 840 watts from the array even though the array is rated about 780 watts. My experience is good with different sizes and one other brand in the mix but all producing near identical voltage.  I was skeptical when I originally bought the panels  but the dealer assured me they will work well together. He also informed me if I add another of the same battery, even though the existing batteries are 5 years old, a new of the same will work just fine with them. My batteries are at about 125 life cycles now and I think they are supposed to give me 1000 cycles and still be 80% efficient.

    • Camper_Jeff___K's avatar
      Camper_Jeff___K
      Navigator
      May 12, 2026

      Here's the installation video from when I replaced and added solar panels a few months back in Quartzsite. You may or may not find it useful. Also, my new Victron 3000 watt inverter charger install is working beautifully

      https://youtu.be/ra7SQb04od8?si=dc5H3TTlBA3X0dZe

      • StirCrazy's avatar
        StirCrazy
        Moderator
        May 13, 2026

        I'll sit down and see what you did when I am on my days off.  these 15 hour days, with the comute, don't leave me much time for anything haha

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