Wire Sizing

Iver · September 06, 2007, 01:29:50 AM

I am installing a new 3k inverter. It is mounted within 2ft. of the battery bank. The battery bank consists of 4 six volt golf cart batteries. What would be the correct size cable from the batteries to the inverter?

I guess I could calculate it out but I'm sure someone here would know.
Thanks, Iver.

Jerry32 · September 06, 2007, 04:03:06 AM

you need the voltage of the inverter to know this Jerry

edroelle · September 06, 2007, 05:46:14 AM

If it is 12 volt, you should you 4 aught.

Even if you batteries are within 2' of the inverter, you still will need longer cable than the 2'. If it is short, the large size will not cost very much.

Do you have the batteries and inverter in separate compartments. This should be done for 2 reasons. 1. Corrosive fumes from the batteries effecting the longevity of the inverter. 2. Hydrogen given-off by the batteries and any relay that may spark.

Ed Roelle
Flint, MI

JackConrad · September 06, 2007, 05:54:59 AM

I always use 4/0 (four/aught) cable (you cannot go too big, but you can go too small). "Bigger is Better" Jack

Gary '79 5C · September 06, 2007, 08:16:34 AM

I agree with the above on the 4/0 cable, but would add that specify that the wire be a super strand, like a welding cable. These are very flexible and still capable to carry the required amps ( 200 - 225A ).

A hydraulic pressed on compression lug would be best to make the termination.

Gary

H3Jim · September 06, 2007, 08:29:33 AM

Although expensive, its a good idea to just go 4/0 with everthing on your p;rimary DC side.

HB of CJ · September 07, 2007, 02:25:51 PM

OOOO with 12 vdc configeration.....OO with a 24 vdc battery configeration. Your set up sounds well engineeered as the run (length) is very short. Your max voltage drop to the invertor will be nil, which the invertor will like best. Bigger cable is better cable for the hi amperage low voltage applications. Use multistrand welders cable if you can find it. More vibration resistant. You will not be disssappointed.

H3Jim · September 07, 2007, 02:36:27 PM

I've got 24 volts, but still went with 0000 wire for everything. And at the batteries - at least before the series portion - they are 12 volts. Its surprising how much voltage drop you can get even with relatively short runs with DC current. Voltage drop is ususally more of a concern than amperage when calculatging DC wiring sizes.