Batteries

mhw
mhw Registered Users Posts: 1 ✭
in General Solar Power Topics #1
I have a very small remote cabin I use maybe a few times a year..It is set up with a 24 volt Outback invertor and charge controller..Want to change batteries and would like to know if 4-6 volt deep cycle would be sufficient..Thanks
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  • 706jim
    706jim Solar Expert Posts: 523 ✭✭✭✭
    #2
    Four batteries should be fine.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,657 admin
    #3
    It also depends on the output of the AC inverter, and what power levels you expect (and ideally, knowing the usage and solar array size).

    More or less, the nominal suggested max continuous load for a FLA Battery bank would be (assuming 6 volt @ 200 AH FLA batteries, 4x series, and C/8 discharge--8 hours from 100% to "Dead"/zero% SoC):
    • 24 volts * 200 AH * 1/8 hour discharge * 0.85 AC inverter eff = 510 Watt "average" load (maybe 2x that for short periods)
    Just trying to set expectations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,175 ✭✭✭✭
    #4
    mhw said:
    I have a very small remote cabin I use maybe a few times a year..It is set up with a 24 volt Outback invertor and charge controller..Want to change batteries and would like to know if 4-6 volt deep cycle would be sufficient..Thanks
    How long is a piece of string? :)
    Well, it depends on what you need.
    I always have more questions than answers. That's the nature of life.
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #5
    A bit more info required . What are your present batterys . How old are they . What size PV .
    What are your loads ?
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • 706jim
    706jim Solar Expert Posts: 523 ✭✭✭✭
    #6
    petertearai said:
    A bit more info required . What are your present batterys . How old are they . What size PV .
    What are your loads ?
    Hence my earlier answer.
    Island cottage solar system with appriximately 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing due south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter which has performed flawlessly since 1994. Outback Flexmax 80 MPPT charge controller four 467A-h AGM batteries. Insignia 11.5 cubic foot electric fridge 1/4hp GSW piston pump. My 31st year.
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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #7
    It is somewhat likely that four 6 volt batteries will be what makes sense. The dearth of info to work with is nominally puzzling. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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