Electrathon America Forum

stan r · Veteran Member

electrical cable

electrathon · administrator

Most teams use battery cable or preferably welding cable. 6 guage is rather small for optimum efficiency, go to at least 2 guage and preferaby bigger.

Aaron

Date: Feb 20, 2010

I agree, we should each use whatever size cable & whatever type we want. I don't like to just play things safe. I like to experiment. If manufacturer tells me their 8 ga. cable will carry over 40 amp for prolonged periods why use anything else? I'd call that optimum efficiency.

electrathon · administrator

Actually, with wire, bigger is more efficient. The rating you are using is the minimum wire that is rated to work. There is no maximum, but at some point you have to stop going bigger. Welding cable is good because it has lots of very small strands in it instead of a handfull of larger strands. This style of wire is also more efficient.

Minimun acceptable efficiency is what you are rating off of (the 8 guage carring 40 amps), not optimum.

Aaron

mhodgertt · EA President

At Willamette we use mostly 4 gauge welding or stereo wire. Any smaller and we seem to not be as efficient and the wires are sometimes a little warm after the race. We can not tell any difference if we go larger than 4 gauge but we don't have any fancy metering systems to actually measure how much power we are using to shove electricity through the wires. We used to use 1 or 2 gauge for several year but then one of our 'dads' who was local electrical engineer told us that with some calculations he thought that any bigger than 4 gauge was an overall efficiency loss as far as resistance loss to weight loss at less than 80 amps. Don't know the 'real' answer but just my 2 cents worth.
Mike

bd64 · Senior Member

Wire size	Ohms/KM	Ohms/ft	Ohms/15ft	IR loss @40 amps	Work lost @40 amps	% of total work lost
2	.5027	1.532E-4	.0023	.092	221 Watt-min	0.4%
4	.8152	2.485E-4	.0037	.142	341Watt-min	0.6%
6	1.296	3.950E-4	.0059	.236	566 Watt-min	1%

This was kind of surprising to me but still less than one poor connection.

Also, this is based on 15 feet of wire and the battery ( times 2 ) from the battery output in another post.

-- Edited by bd64 on Saturday 20th of February 2010 08:31:18 PM

-- Edited by bd64 on Saturday 20th of February 2010 08:31:44 PM

electrathon · administrator

mhodgertt wrote:
... any bigger than 4 gauge was an overall efficiency loss as far as resistance loss to weight loss at less than 80 amps.

I could easily see this. The electrical part would be more efficient but the extra weight you are carrying would subtrace from the total efficiency factor.

stan r · Veteran Member

Isn't it amazing what a person can learn when we share ideas. I still like stereo cable.

electrathon · administrator

Stereo cable is very close in characteristics to welding cable. It does have one big advantace, it looks cooler. I remember one of the cars having it a few years ago. If I remember correctly, it was about 0000 in size. The stuff was huge, bigger than your thumb.

meangreen · teacher / board member

I use #4 (multi strand) cable that I buy at Lowe's. It weighs about half what welding cable weighs, costs a lot less than stereo cable, and I haven't noticed any appreciable difference in performance.

alexbarb · Newbie

I think you shouldn't use this wire as a battery cable..Because Every type of wire is manufacture according to its use. It means that wire should be used according capacity also. plastic hats | wire plastic