Generator / Battery Charging Question

TenMile Solar Expert Posts: 62 ✭✭
Hey all,

At our cabin, we occasionally need to recharge our battery string if we've had a stretch of cloudy weather and the family is there for an extended period.

We happen to have a Smart Charger that is capable of charging at 100A/15A/2A and will automatically shut off when the batteries are fully charged (this is the unit).

Here's the question -- is it better to run the generator for a short duration using the 100A setting on the charger, or 6x longer and charge them at 15A? Clerk in the store suggested only using the 100A setting to boost a car battery for emergency starting, and 15A for general recharge settings. Not sure he was aware that we might want to put 150-200Ah into a battery string.

Don't want to damage the batteries by doing the wrong thing here so would appreciate the advice. My system is outlined in my sig below.


  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Generator / Battery Charging Question

    No, you definitely don't want to put 100 Amps to a 450 Amp hour battery bank. That would be charging at 22%. AGM's can take that, FLA's can't. Besides, the charger was not meant to provide that rate for long; it is indeed meant for booster.

    What you really want is a charger more suited to the application:
  • BB.
    BB. Super Moderators, Administrators Posts: 33,477 admin
    Re: Generator / Battery Charging Question

    What genset do you have?

    In any case, as Marc said--the "100 booster" may be rated anywhere from 30 seconds to a few minutes of duty cycle before it needs to be turned off and cooled down.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset