State of Charge Question

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verdigo
verdigo Solar Expert Posts: 428 ✭✭
in Solar Beginners Corner #1
I have a 48 volt 464 ah bank of GC2 batteries. My solar system is not in use yet. Hopefully I will be getting the electrician and then the inspector in and out over the next couple of weeks. I have 1120 watts of PV installed of the planned 3600 watts (give or take) but what I do have is functioning and connected. MY SG readings are like 1.275 across the board and the bank is floating. I have the classic's end amps set for 4.6

I am worried that they are a bit over charged and was wondering if I should just turn the charge controller off and maybe just top them up once a week or less until I have enough PV to draw them down and recharge quickly? I hooked a space heater up to the inverter (1400 watts) to see what the panels would do and they were putting out 19.5 amps in good full sun according to the classic, but still 4 amps shy of 5% charging amps needed for the bank.

Thanks

Dennis
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    Re: State of Charge Question

    How often do you refill the bank (monthly--probably overcharging a bit, every two months--about right, every few weeks--too often). You might cut back on the float voltage/absorb time for now to ease up on water usage (if excessive).

    If your system is setup correctly--Then you should not need to disconnect/turn of the solar when no power is being used.

    If you are not there presently to monitor the system--You might want to just turn on the solar charging once or twice a month (for a day or two--all loads disconnected/turned off) just to make sure that something does not "run array" while you are gone and you have yet to "prove" the system is stable.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #3
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    Re: State of Charge Question

    I have been charging weekly maybe every two weeks when it was cold out. Float is set at 54 volts, Absorb is 58.4 for two hours, with end amps at 1% or 4.6 a. I think I will hook up some loads this weekend and see if I can discharge down to around 60 to 75% SOC and see if I can re-charge to a lower SG and then experiment with float voltages a bit. I have yet to add any water to any of the batteries at this point.

    Thanks

    Dennis
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