So here's a dumb electrical question

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mechanic190

mechanic190

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I am working on my electrical system on my drag racer and was curious with the battery cables.

1/0 battery cable measures 0.32" in diameter. 12 ga measures .08" in diameter. If you wrap 4 12 ga wires together in the same ring terminal connector you have the same diameter as 1/0. Whats the disadvantages of running a poor mans battery cable like that? I have used this on work over rigs in the oil field because 12 ga was the biggest I carried and I can guarantee that nobody has replaced those wires with actual cable.

Curious because I'm debating on doing it to try to get a better grounding system than just bolting everything to frame rail, and money is real tight at the moment
 
If you are set on doing this, and I'm sure obvious to you, "go big," that is, lean towards bigger than smaller

What I would do is find a chart for ampacity (current) and make sure it's for 12V automotive use, not AC power.

Compare ampacity ratings of your 1/0 to 12ga, and add enough 12ga cables to total "at least" that much. I would not go by appearance.

If you can pull it off neatly, there is nothing wrong with that approach I guess. Downside for me, is you'll have a lot of wasted space with insulation.
 
That's a good point looks like about 6 12 ga to meet the same load carrying capacity of 1/0. 4 wires will meet 3 ga
 
Downsides: more points of failure, a single point failure might could overload the remainder and cause a ripple effect failure, more work.

Upsides: none, unless the smaller wire is very cheap.

Before doing it, I'd scour wrecking yards for trucks and vans and yank the longest cables you can find. Likely a similar cost as 4x 12ga (any that's actually load rated) and so long as you're not picky about wire color you should have plenty of pickings from vehicles already missing their engines.
 
4 12 guage is a lot less area than 1/0, 4 12 in a line is as wide as 1/0 , but 4 does not fill the area of a 1/0. draw a circle and see what I mean
 
Again, you cannot go by physical area. You must go by ampacity. One problem of course is that all charts are not equal LOL

Here for example:

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

This chart

http://assets.bluesea.com/files/resources/newsletter/images/DC_wire_selection_chartlg.jpg

In the 20ft "critical" column, this would suggest that no 0 is good for 150A

In the same 20ft column, 12 ga is "not shown" but borderline at 10A. This would suggest that FIFTEEN 12ga wires are needed to equal no0

Other factors you must consider is strand size. In AC especially higher frequencies, you get into "skin effect" which requires larger conductor size. DC does not suffer this, but battery cable typically has larger strand size, which would surely negate any physical comparison

I didn't bother to check, the distances in that chart are likely for two wires, as this was from a marine oriented site.
 
First of all, dumb questions is my thing, please don't try and take my crown! Lol It sounds logical to me, but that's the scary part . LOL I finally bit the bullet a couple of years ago and had a correct cable made. Of course it's the expensive part of relocation. "Poor mans battery cable" LOL I swore I wasn't going to spend a nother dime on the duster this year - I mean it ! I'm done !! That's it !!! :banghead:
that was about $1,000 ago #-o
 
Spend $75ish on a good 1/0 welding cable starter wire and be done with it.

I make them if you are interested.
 
I see nothing wrong with "the idea" of this depending on circumstances. An alternator charge wire is a good example, as most automotive outlets don't carry no6 wire. Therefore, paralleling no 12 or 10 makes sense.

This might also be a great trick in an emergency, somebody burns a battery cable on the headers etc.

I think you get enough no 12's in there for starting you will have a REALLY big cable.
 
I did have to use the poor man battery cable lol. I finished my positive side with the 1/0 and had enough left over to put in a decent ground system. Only used one ground wore from the cab to my grounding lug on he frame. But I got it running and everything seems to work great no issues. My cables in the back are 1/0 and then a decent sized factory cable attached to frame. Ground from engine to frame is 1/0 and alt positive side is 4 ga. So I think I'll be alright and save a little till I have don't have such a long laundry list to do
 
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