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cliffy49's avatar
cliffy49
Explorer II
Jun 19, 2021

Watts needed

I have read where folks suggest any where from 1 to 2 watts of solar per ah of battery. My question, is this based on battery rating (ie 215 AH) or is it based on useable amp hours(105)?

All replys are greatly appreciated.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Jun 19, 2021
    One to two watts per battery amp hour is the standard but it depends on where you are (up North, two) and whether you like campsites with lots of shade during the day. I’m currently 240 battery amp hours and 300 solar watts. Don’t cheap out on wire or the controller…then you can easily add another panel if needed.
  • jdc1's avatar
    jdc1
    Explorer II
    Jun 19, 2021
    100 watts of solar at 12v is 8.33333amps. If you have a 130Ah battery and it is down 50%, it will take in excess of 10 hours of FULL sunlight to charge it (the charge rate slows as it gets to capacity). So, it might take 2 days to charge one battery.

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