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DarkSkySeeker's avatar
DarkSkySeeker
Explorer
Apr 19, 2020

Solar Charging and Amp Hours

Is the amperage from a solar panel constant as the battery it is charging charges up?

I.e., as your battery reaches full charge, the current drops to zero either via the charge controller or the equalization of the panel and battery, right?

So this simple math is false? 120 watt panel, 12 volt system, 10 amps, 10 hours to charge a 100 Amp Hour battery?

24 Replies

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  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Apr 19, 2020
    There are still experienced RVers with dumb controllers?
  • jdc1's avatar
    jdc1
    Explorer II
    Apr 19, 2020
    It really depends on your charge controller. Some are "smart chargers", slowing the charge rate as the battery nears the full stage.
  • MrWizard's avatar
    MrWizard
    Moderator
    Apr 19, 2020
    A 120w panel does not output 10amps

    Out put it more like 7 amps

    Full Working voltage of a 12v panel is around 17v,
    Output from the controller is 14.x to properly charge the battery

    12v won't charge a battery, a battery at 12v is only 50% charged/capacity
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Apr 19, 2020
    Yes, false. Charging to 80-85% goes quickly with the battery accepting everything or almost all sent to it. During the absorption phase the battery accepts less and less.

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