Battery Bank Interconnects Wire Sizing?

verdigo
verdigo Solar Expert Posts: 428 ✭✭
in Solar Beginners Corner #1
Just a quick question: For 8 GC2 batteries for single or multiple strings will 1/0 cable be okay? 48 volts. Looking at 4 KW Inverter

Thanks

Dennis
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Battery Bank Interconnects Wire Sizing?
    verdigo wrote: »
    Just a quick question: For 8 GC2 batteries for single or multiple strings will 1/0 cable be okay?

    Thanks

    Dennis

    It depends on how much current is expected.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: Battery Bank Interconnects Wire Sizing?

    that would depend on a few factors such as the battery bank voltage, the max current drawn, and the length of the wire run between the batteries and load or batteries and charge source. what this ultimately refers to is the voltage drop as well as the base amperage the wire can handle.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #4
    Re: Battery Bank Interconnects Wire Sizing?

    It would probably be fine, but for $2.00 more per battery you can have 4/0 and never worry about it.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #5
    Re: Battery Bank Interconnects Wire Sizing?

    The battery bank will be 48 volts, and the Inverter will be an XW 4548. Near term charging will be a 3.4 KW array through a Classic 150.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #6
    Re: Battery Bank Interconnects Wire Sizing?
    Blackcherry04 wrote: »
    It would probably be fine, but for $2.00 more per battery you can have 4/0 and never worry about it.

    Thanks 4/0 it will be then. I am planning on doing some wiring this weekend. No worrying is worth the extra money.

    Dennis
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
    Re: Battery Bank Interconnects Wire Sizing?

    4500 Watt 48 Volt inverter will draw around 100 Amps peak continuous. As such 1/0 actually would work as it is good for 150 Amps.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #8
    Re: Battery Bank Interconnects Wire Sizing?
    Cariboocoot wrote: »
    4500 Watt 48 Volt inverter will draw around 100 Amps peak continuous. As such 1/0 actually would work as it is good for 150 Amps.

    This would be good as I have about 20' of 1/0 cable. I also have some used welding cable from a dead welder I inherited with some age on it but the insulation still looks good. I think it may be 2/0. I can't see any numbers on it but I haven't looked too closely. Is there a number to measure the diameter to tell for sure?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Battery Bank Interconnects Wire Sizing?

    You can measure wire diameter but ... you can also be pretty inaccurate at it (it's easy to make a mistake).

    This Powerstream chart shows the diameter for wires. 2/0 would be 0.3648"

    Welding wire can also be trouble to secure in lugs because the strands are so fine. With any used wire inspect the insulation carefully and look for signs of corrosion inside.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #10
    Re: Battery Bank Interconnects Wire Sizing?

    I kind of like Battery Interconnects like a Buss Bar, The bigger the better. The cost of going big ( 4/0 ) is minor in the scheme of things.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #11
    Re: Battery Bank Interconnects Wire Sizing?

    Just looking at the Inverter wires that came with one of these Midnite E Panels I got off E bay, and with all the info on the wire I can glean "600V or 10269 1000V VW-1 VW-1 2 AWG and it looks like a temp rating of 105 degrees C at 600V. The E Panels are made for 48 volt Outback Inverters, so I am assuming that 2/0 wiring throughout for all of my battery bank wiring and I should be good to go?

    Thanks again for the help here
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
    Re: Battery Bank Interconnects Wire Sizing?

    Whether or not you're "good to go" depends not on what it was used for but what it is going to be used for. 2 AWG should handle 150 Amps. That's roughly 7kW on 48 Volts or 3.6 kW on 24 or 1.8 on 12. It sounds like they were using FX3648 inverter(s) and rated the DC wire for full surge capacity, which is good.
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  • verdigo
    verdigo Solar Expert Posts: 428 ✭✭
    #13
    Re: Battery Bank Interconnects Wire Sizing?
    Cariboocoot wrote: »
    Whether or not you're "good to go" depends not on what it was used for but what it is going to be used for. 2 AWG should handle 150 Amps. That's roughly 7kW on 48 Volts or 3.6 kW on 24 or 1.8 on 12. It sounds like they were using FX3648 inverter(s) and rated the DC wire for full surge capacity, which is good.
    Actually the Inverter cables came with the E-Panels, witch are MNE125 AL and built by Midnite for Outback's 48 volt 3.6KW Inverters. if I follow Blackcherry's advice on the 4/0 cable I should probably make the inverter cables the same as well.

    Thanks again
    Dennis
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #14
    Re: Battery Bank Interconnects Wire Sizing?

    In terms of importance:

    1). All battery cables must be able to carry the maximum expected current on them.

    2). Cables between battery bank and inverter (or other long run) must be able to carry this current with minimal Voltage drop.

    As such, cables connecting between batteries may actually be smaller than those going to the inverter. They usually aren't, because if you've got to by six feet of whatever gauge to go to the inverter another two feet or so to connect between batteries won't be much of a hardship. :D
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