What should the discharge settings be for 6 volt lead acid solar batteries?

TheVillagesGuyTheVillagesGuy Registered Users Posts: 9 ✭✭
What should the discharge settings be for 6 volt lead acid solar batteries? Maximum Discharge Current Percentage and Maximum Discharge Time Interval? My setup is 16 6 volt batteries in series and parallel = 48 volts and 460 ah.

Comments

  • BB.BB. Super Moderators Posts: 27,055 admin
    The standard for flooded cell lead acid batteries for discharge current use the 20 hour capacity number "C" of the batteries:
    • C/20 hour discharge or 5% is a nice easy discharge and a good average discharge for 5 hours per night for 2 nights (10 hour discharge) and leaves 50% still in the battery bank.
    • C/8 hour discharge or 12.5% (or 13%) is the maximum rated discharge suggested (for less than 4 hours to 50% discharge)
    • C/5 hour discharge or 20% discharge is maximum short term discharge (minutes to an hour)--Tools, pumps, etc.
    • C/2.5 hour discharge or 40% discharge rate is maximum for surge current, starting motors, etc. (seconds to minute).

    You have a 460 AH battery bank, use that for "C".

    Is this what you are looking for?

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • TheVillagesGuyTheVillagesGuy Registered Users Posts: 9 ✭✭
    BB. said:
    The standard for flooded cell lead acid batteries for discharge current use the 20 hour capacity number "C" of the batteries:
    • C/20 hour discharge or 5% is a nice easy discharge and a good average discharge for 5 hours per night for 2 nights (10 hour discharge) and leaves 50% still in the battery bank.
    • C/8 hour discharge or 12.5% (or 13%) is the maximum rated discharge suggested (for less than 4 hours to 50% discharge)
    • C/5 hour discharge or 20% discharge is maximum short term discharge (minutes to an hour)--Tools, pumps, etc.
    • C/2.5 hour discharge or 40% discharge rate is maximum for surge current, starting motors, etc. (seconds to minute).

    You have a 460 AH battery bank, use that for "C".

    Is this what you are looking for?

    -Bill

    I am looking for the bottom two settings shown in this pic.
  • BB.BB. Super Moderators Posts: 27,055 admin
    I would suggest starting at:
    • 460 AH / 2.5 surge = 184 Amps @ 10 seconds
    • 184 amps * 48 volts * 0.85 inverter eff = 7,507 Watt AC surge support

    I am not an expert--And, of course, your wiring has to support such current too.

    -Bill

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