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View Full Version : Battery Cable and Wire Sizes



RickR
01-14-2004, 08:16 PM
Size with TOTAL length of wire. From battery to equipment and back to ground.
Watts/Voltage=Amps
http://www.donzi.net/photos/rryan53wire.jpg
http://www.donzi.net/photos/rryan53wirea.jpg

RedDog
01-15-2004, 07:05 AM
Good reference data - but how many amps does a typical starter pull and what would be a conservative estimate for continous power requirements?

MOP
01-15-2004, 07:57 AM
A little overkill is always good, I run #2 on the 16 and will do the 22 a tad heavier with dual bats. Average starter that I have tested came up about 80 amps, so with #4 you have a 20 amp margin on a 10 foot run. With a solenoid in the circuit I always go up a size, maybe not needed but gives me peace of mind. On dual battery setups I use a size from bats to switch more if not real close and #0 from common to the engine. Always buy a heavier switch than necessary at least one amp rating up, don't be cheap switches can let you down and cheap is cheap! Two bats throw a lot of amps on a cranky engine. Don't care for the brass bat terminals the acid corrodes then quicker than the lead, most of use use the wing nuts though. All connections should be sprayed with Pro Clean or similar terminal connection spray. Continuous draw or return is a hard call depends on accessory usage and charge rate. Big alternators can heat things up, wire size must be increased. I much prefer to run the alternator lead direct to the switch common or the battery rather than interrupt it at the solenoid, every connection eliminated is a future headache eliminated.