Battery Relocation Cable Size?

[fredhlynch2]

Need advice. Going to relocate my battery to the rear of my bagged truck. What gauge wire is best for that long of a run? 2 or 4 gauge? Running a full Accu-Air system which pulls a good deal of amperage. Running a yellow top Optima battery. Where should I run the ground to, frame or engine block?

Can anyone recommend a good supplier or brand name for battery cable wire?

[bpmcgee]

This chart shows recommended wire gauges for run length and amperage:

https://www.bluesea.com/resources/1437

The TL-DR is that if you're okay with a 10% voltage drop, 4 gauge is suitable for runs less than 20 feet and below 100 amps, 2 gauge to 120 amps, 1 gauge to 150 amps, and 2/0 to 200. If you want only 3% drop, those amperages go to 80, 120, 150, and 200 respectively.

I don't know your air bag system, but generally the draw you have to accommodate for the battery lead is the starter, which may draw 150 amps or more at 12 volts -- and even more, of course, if the voltage drops due to a thin wire.

B

[Dead Parrot]

I would use the chart link and figure that starting is a critical circuit. Think below zero, blizzard, someone left the lights on for a couple hours,.... The less drop the better.

Should be able to use the frame for the negative side but run a matching size wire from a front frame point to the engine block. Otherwise, all the starting current will try to go through the too small grounding straps.

[fredhlynch2]

Thanks guys. All good info.