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icanon's avatar
icanon
Explorer
Sep 10, 2015

How much solar power needed for?

Hey everyone! I do a lot of astronomy and planning to go on the four day 'off grid' trip. I'm wondering how much solar power do I need? Basically just need to keep my 12V RV battery charged. I just need the battery to keep the propane fridge, water heater running and water pump to shower with (no microwave, a/c, or TV). So how much of a solar power kit do I need?

Thanks. :)

29 Replies

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  • JiminDenver's avatar
    JiminDenver
    Explorer II
    Sep 10, 2015
    Just four days? You should be able to get through that with the use you describe on a decent, well charged battery. A extra battery and LED lighting would be a good start. Otherwise a 100w portable would easily keep up with the limited use.
  • Helimech's avatar
    Helimech
    Explorer
    Sep 10, 2015
    100 watts and keep it pointed to the sun and that should do the trick.
  • TucsonJim's avatar
    TucsonJim
    Explorer II
    Sep 10, 2015
    I have two 100 watt panels and similar usage as you. The two panels are overkill. I'm usually fully charged in 3-4 hours of sunlight. For your use, I'd probably go with a single 100watt panel.
  • fitznj's avatar
    fitznj
    Explorer
    Sep 10, 2015
    I have a ~150W solar panel and 2 Walmart batteries; Keep me going almost indefinitely. I have not camped during the winter yet with this set up.

    I have digital voltmeter hooked up to the battery and can keep a constant eye on the state of the batteries. My batteries charge even on an overcast day (like today in NJ) - but not as efficiently.

    Gerry
  • 2oldman's avatar
    2oldman
    Explorer II
    Sep 10, 2015
    icanon wrote:
    I want to go as cheap as possible.
    Everyone does. One 120w panel will be fine.

    Seriously, twice a year, 4 days.. go real cheap and just carry a spare battery. Your usage is close to nothing, unless it gets cold and you need furnace.
  • icanon's avatar
    icanon
    Explorer
    Sep 10, 2015
    smkettner wrote:
    Depends on conservation. You could make four days fine if you turn nothing on.
    I will suggest two batteries and 200 watts to get started.
    Will also depend on getting a sunny campsite.


    I just need it to keep the propane fridge, water heater running and water pump to shower with.
  • time2roll's avatar
    time2roll
    Nomad
    Sep 10, 2015
    Depends on conservation. You could make four days fine if you turn nothing on.
    I will suggest two batteries and 200 watts to get started.
    Will also depend on getting a sunny campsite.
  • icanon's avatar
    icanon
    Explorer
    Sep 10, 2015
    Happy Prospector wrote:
    How much money do you have for this project?


    I want to go as cheap as possible, it's only to be used maybe twice a year the rest of the time I'm camped with full service.

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