voltage drop 12- 15 ft inverter cables

John XW NY
John XW NY Solar Expert Posts: 50 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
What would the voltage drop be from 12- 15 ft 4/0 cable from inverter to battery bank?

what would be the proper method of dealing with this issue?

is 4/0 good enough to negate that?
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: voltage drop 12- 15 ft inverter cables
    John XW NY wrote: »
    What would the voltage drop be from 12- 15 ft 4/0 cable from inverter to battery bank?

    what would be the proper method of dealing with this issue?

    is 4/0 good enough to negate that?


    Depends on the Amps drawn, more amps = more drop
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    #3
    Re: voltage drop 12- 15 ft inverter cables

    Assuming a XW 4024 used at full capacity (8kW surge?), 85% inverter efficiency, and 21 volt minimum:

    Amps = 8,000 watts * 1/21 volts min * 1/0.85 eff = 448 amps maximum

    You have 15' run of cable, and for this calculator (voltage drop calculator) , use 2x15'=40' of wire, 100F--you get:

    Drop= 0.70 volts
    %Drop= 2.94% (based on 24 volts)

    For 4kW max operating current, 0.35 volts and 1.47% drop.

    In general, keeping those heavy current leads between charge controllers and inverter to the batteries as short as practicable is a good idea.

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