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jwc99's avatar
jwc99
Explorer
Sep 20, 2015

Another solar question

Didn't want hijack anyone else's thread so here's my question. I was given 2 solar panels to use with my tt. They are Siemens SM55, 55 watt, 17.4 volt, and 3.15 amp each. I will use this setup 1 time a year when I make my Smokey Mountains trip, the only time I primitive camp. I have one 12 v 105 amp hour battery on the trailer. The only power we use in the trailer is for about 15 min of led lighting and each of us a quick shower at night. I would like to use the panels to help with the battery. Since the panels are only capable of 3 amps each would I do better running them separate with a cheaper controller or should I tie them together? I don't want to spend a bunch of money on a controller if possible. What would you recommend?
Thanks
  • groundhogy's avatar
    groundhogy
    Explorer
    Sep 20, 2015
    two 55 watt panels.... one battery???
    jeese. Seems to be lots of solar power and not much battery or
    power usage. you need a charge controller so you don't boil your
    batteries is my thinking.
  • jwc99's avatar
    jwc99
    Explorer
    Sep 20, 2015
    I usually get 2 days out of my battery before I take it off to charge. We stay 8 nights and what I usually do is take the battery off and charge it, I have a plug in my truck that charges the battery as we ride around. I was thinking about buying another battery and adding it to the camper for added support. This will be a portable setup, not something I will mount on the camper.
  • 2oldman's avatar
    2oldman
    Explorer II
    Sep 20, 2015
    For 8 nights, with that little use, a good fully-charged battery should last. I'd bring another along just in case.
  • MrWizard's avatar
    MrWizard
    Moderator
    Sep 20, 2015
    a cheap $20>$30 controller from amazon either a 10amp or 20amp PWM controller
    put both panels wired parallel together
  • KD4UPL's avatar
    KD4UPL
    Explorer
    Sep 20, 2015
    There's no advantage to using a second controller. Connect the panels in parallel and use one charge controller. I would add a good digital voltmeter if the charge controller you choose doesn't have one. The little LED "battery meter" in most RVs is useless.
    I think you will be surprised how much power you will have. We have 100 watts and 2 batteries and never run out of power when off the grid.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Sep 20, 2015
    Use a single controller. Panels can smash. I'd recommend a permanent roof installation.
  • jwc99's avatar
    jwc99
    Explorer
    Sep 20, 2015
    My buddy, after hearing me talk about getting a controller, just gave me one. I now have a Schneider C40. Will it work for what I am doing? The price was right so I hope it will suit my needs. I still want this to be a portable setup, I may mount it when I get the new camper. If I purchase another battery to add to the trailer and connect the solar setup would I be in good shape? What would be my best plan?

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