Corrections made on 24 volt Battery Bank please advise - Diagram Included

cdrudge
cdrudge Registered Users Posts: 5 ✭
in Off Grid Solar & Battery Systems #1
1 Group each of 8 positives and 8 negatives will be attached to bus bar. Each string will be fused with 200 amp fuse.
all interconnecting cables will be 1/0 and will be 24 in in length.
Thank you for your time and advice.

Sincerely Always Learning :blush:

ATTACH=CONFIG]5296[/ATTACH]
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #2
    Re: Corrections made on 24 volt Battery Bank please advise - Diagram Included

    Have you thought about building a 48V system instead?
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  • cdrudge
    cdrudge Registered Users Posts: 5 ✭
    #3
    Help need with 24 volt battery bank

    1 Group each of 8 positives and 8 negatives will be attached to bus bar. Each string will be fused with 200 amp fuse.
    all interconnecting cables will be 1/0 and will be 24 in in length.

    Is this the best configuration for what I have to work with?
    Thank you for your time and advice.

    Sincerely Always Learning

    Attachment not found.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Help need with 24 volt battery bank

    3000 watt 24 volt inverter should, at a minimum (to use 3kW continuous power):
    • 3,000 watts * 1/21 volts battery cutoff * 1/0.85 inverter efficiency * 1.25 NEC derating = 210 Amps minimum branch circuit fuse/wiring/breaker.

    For a multiple string battery bank with 3 or more parallel battery strings, I would suggest that 1/2 the maximum current above should be a "large enough" protective device... I.e., >105 amp series fuse for each battery.

    And where the batteries come together, should be a minimum of 210 amp rated fuse/wiring to inverter (round up to next "standard" device at a minimum). You do not want 200 amp * 8 parallel fuses or 1,600 amps available on the positive battery bus to any/all loads/charging sources.

    Fusing is to protect wiring. You can have heavier wiring (lower voltage drop) but a lower fuse rating (no need for a 400 amp fuse on a device that only needs a 200 amp circuit.

    Fuses should not blow at 80% of rated current and will blow by 100% of rated current (in minutes to hours). The 1.25 max continuous current is the derating for the wiring and fuses/breakers by NEC.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Steve Higgins
    Steve Higgins Registered Users Posts: 13 ✭✭
    #5
    Re: Corrections made on 24 volt Battery Bank please advise - Diagram Included

    I would suggest that you "KEEP IT SIMPLE".

    Attachment not found.

    Another issue, is in my experience with a 24 Volt inverter and only 1/0 cable you are going to run into problems with charging your battery bank... I would suggest that the absolute minimum would be 2/0 cable.

    Also 4 Parallel strings of Batteries isn't optimum... You could also potentially run into problem keeping the parallel strings properly charged.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #6
    Re: Corrections made on 24 volt Battery Bank please advise - Diagram Included

    I moved these two threads into one... Easier to keep all the replies on topic.

    The ATTACH tags seem to be a bit screwy... Not sure what is going on.

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