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Guage multiplication?

346 Views 6 Replies 3 Participants Last post by  Koverchenko
Hi all. I've tried Googling this, but cannot find a clear answer. I know you can run various sizes of wire within a circuit. For example, one would run 0 or 2 guage wire when relocating a battery to the trunk due to distance and power loss, etc. But, then the rest of the wires are 4 guage and higher.

I also know that "The Big 3" upgrade is effectively adding another wire to increase the efficiency and/or power running between those three places. My question is, is it possible/reasonably safe to use that concept when relocating the battery?

Basically, 2/0 guage wire is expensive. Higher guage wire is less so. Could I conceivable run, say two 4 guage wires and have it equal a 2 guage wire? Thank you in advance.
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Buy batteries from some regular manufacturers, which may not have any problems and can improve your battery life.
I appreciate the reply. But, my question is not about battery size. What I'm wondering is, could I run multiple lines of a lower guage wire to compensate for any voltage drop over a longer distance like the length of a car, as opposed to a short distance like is done for the BIG 3 upgrade. I will be getting a reliable replacement battery. I'm just trying to figure out if it's sufficient to run multiple lines, or do I need to spend more for a higher guage wire and only have one line. I know one would be physically easier. But, I'm already planning on paying for correct OFC wire. And, that's much more expensive when you look at the difference between 0, 2, and 4 guage wire.
I don't know the formula for equivalency between multiple smaller gauge wires and one larger gauge. I'm sure there is a way to calculate it, I just haven't seen it. But to answer your question, yes, what you're proposing is correct, but I don't know the actual gauge wire(s) you will need.
The question I have for you is, how did you determine you need 2/0? That is VERY heavy. You will have voltage drop when running low voltage/high current (as drawn by the starter motor) over distance, but that seems way overkill to me.
I did the rear-mount battery on an old Mopar I'm fixing up and to figure what I needed, I used a clamp on ammeter to measure the current while cranking. As I recall it was about 190 amps. I don't remember off the top of my head what gauge wire I used but I think it was single ought, aka 0. I can confirm that when I get home and look at my notes.
Something to keep in mind with wire ampacity is that it's rated for continuous duty. In other words, the max rated current non-stop. Starters don't work that way, and while you don't want to undersize because of the voltage drop issue which will give you a slow crank, there's no benefit to oversizing.
The problem you may run into with multiple wires instead of one larger one is that the terminals are not designed to crimp onto more than one conductor. I'd be worried at least one would wind up insufficiently crimped. Also, use welding cable for the best results. It uses a very fine strand that will give the least drop and will be very flexible and easy to route.
If I have time tonight I'll post up some info and pics of what I did on that old car. The take away there being if 0 cranks over a small block V8, you should be able to get away with something smaller considering a smaller starter and a shorter run. But again, I'll confirm what I used.
Thank you for that. Regarding the wire size, I'm sort of a "brick house piggie". Lol. As in, it might be overkill, but if it doesn't hurt its better to go over than under. Bricks vs straw, etc. I know that the OEM wire in the engine bay is 4 guage. I just thought I'd need something much sturdier since there will be a 15 foot span where there could be a drop. Additionally, if I used a really heavy duty wire, I could conceivably not need another wire run if I ever wanted a serious sound system.
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