Battery Cable Gauge

[Retired Phil]

Does anyone know the average gauge size for a battery cable???

Phil

[fulltiming]

1/0 is used in small 6 and 8 cylinder cars for the primary battery cables, 2/0 for diesel engines and 3/0 to 4/0 for heavy equipment engines.

When I had a new 2500 watt inverter installed in a previous motorhome, they used 00 gauge wire (also written 2/0) which has a diameter of 0.57". Larger diameter wire will result in less voltage loss over a longer distance.

[encantotom]

hi all,

i am gonna make some new battery cables. so are they 2/0 on our coaches?

i was thinking i was gonna need 3/0 or 4/0, but after looking at 2/0 cables i think that is what is on mine already.

i will go measure the outside diameter with a caliper and check for sure.

so is 2/0 ok for the coach and engine batteries?

thanks

tom

[JohnC]

Rule of thumb #1 - The more copper the less the resistance

One of those rare instances where it's pretty hard to use too much

Rule of thumb #2- Keep all connections clean, especially the chassis ground. I can't begin to guess how many perfectly good starters and alternators have been replaced/rebuilt because of poor connections, especially chassis grounds. Removing the suspected unit often cleans the 'bad' connection, and then when the new unit corrects the problem, the incorrect diagnosis is assumed as right-on.

One quick method to check for bad grounds or loose connections is with a non-contact thermometer. While the better-half is cranking the engine, quickly check for heated connections. Resistance creates heat and loose connections will normally be much hotter then the rest. Same for cables- if your cables are getting fairly warm I would increase the size. You can also use the non-contact thermometer to check your shore power connections for heat, wheel bearing temps, restrictions in your radiator (cold spots), brakes dragging, tire temps etc. I keep one just inside my door and routinely check my tire temps everytime I stop at a rest area.

[prarieschooner]

Here is a link that may be helpful to you in selecting wire size. You will need to use a good Crimping Tool when you make the Cables up.
Hope that this is helpful;
http://www.westmarine.com/webapp/wcs/stores/servlet/westadvisor/10001/-1/10001/MarineWire.htm