Max AGM charging Amps

tr0ytr0y Solar Expert Posts: 99 ✭✭✭
Hey all - 

Trying to understand what / how I should be charging my 12V 600Ah bank of batteries in my RV. I want to make sure that I don't cook the batteries or not get them enough charge. 

3 200Ah 12V AGM batteries wired in parallel. 

They started the the morning between 12.3V and 12.4V and now charging away in bulk @ 13.6V at about 64A. Mfg specs say to absorb between 14.5 and 15V and then float @ 13.5 to 13.8V

What I want to know or how to figure out is how to properly calculate how much amperage I should throw at the batteries or is there a limit I will hit ?



  • jonrjonr Solar Expert Posts: 1,386 ✭✭✭✭
    The manufacturer should say, but if not, I'd limit current to 120A (20% of C20).

    Enough charge is mostly a matter of absorb termination criteria and absorb time.

    I am available for custom hardware/firmware development

  • Marc KurthMarc Kurth Solar Expert Posts: 1,009 ✭✭✭✭
    edited September 2018 #3
    With absorb and float voltages that high, I would assume that you have house branded batteries in the Ritar/UPG class of AGM. In that case, you DO want to keep that charge rate down to 20% or less as jonr already said!

    To repeat what else he said: Follow the manufacturers recommendations! 
    I always have more questions than answers. That's the nature of life.
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