Battery relocation - thoughts

[Def]

Im going to be relocating my PC680 to either the pass. rear seat area, or by the fuel pump cover area.

What gauge wire you guys using? Calcs suggest a 4 ga would be fine upon startup, then the alternator takes over.

I'm also thinking of making my own holddown. Any pics of what others have done?

[McCoy]

FWIW, I used 8 ga in the sentra when I mounted my PC680 under my drivers seat and it worked fine for the 2 years I had it like this, but I do think 4 ga would be better if I was to do it again.

[cazman]

Just curious, why the move? Is it for weight distribution? If not they way I am mounting mine is directly under where the factory one sits, in a sealed metal box (i have a drycell)
This keeps my cables short and my engine bay free with virtually no headaches.

It will improve weight as its lower but I understand its still forward of the wheel line.

As for you actual question, 4 ga would be a min, and i have seen many problems with these setups, some needing the battery to be grounded every foot back the bay.

[jmauld]

Im going to be relocating my PC680 to either the pass. rear seat area, or by the fuel pump cover area.

What gauge wire you guys using? Calcs suggest a 4 ga would be fine upon startup, then the alternator takes over.

How many amps does the starter draw? What type of wire are you going to use, Aluminum or Copper?

[McCoy]

The starter in a FWD SR draws less than 80 amps, since that is what I was using... not sure how much more, if any, the RWD SR starter uses.

[Epstein]

I didn't have an issue with 4ga on a hatch I did over the period of 3 years. That is until the tiedown broke free and acid dumped out all over the place (oops). I used a big 200A inline fuse for protection from battery cable shorts at/inside the battery box. The stock setup has no such fuse. Run that directly to your starter, then drop the other 2 battery cables (system and alt) to the starter as well. Makes a very clean install with minimum length wires and no fussy distribution blocks.

[Def]

I was going to put a terminal post in the back of the engine bay and use the stock battery cable on it.

4 ga should be able to flow more than the PC680 can provide with less than half a volt of drop.

I'll be using stranded copper cable of course - I'd never use aluminum wiring on a car... in fact, I don't think I've ever seen aluminum wire on a car.

Won't be using a box since the PC680 is a drycell, and was going to mount it on its side, but will be doing an inline fuse by right it and of course covering the terminals.


Mainly doing it for weight distribution. Trying to lighten the front and get more weight on the passenger rear.

[jmauld]

4 awg wire is only good for 85 or 95 A based on the temp rating of the insulation. That info comes from the NEC which assumes longer runs then what you're going to find in a car as well as wire that is likely inferior to what you will be using, but I personally would still follow it. Any 12V car battery can exceed that, including the PC680. I would size the fuse according to what the NEC suggests. That's just my opinion.

[McCoy]

I just went back through some of my old posts on another forum... I was using 4 gauge wire, not 8.

[2Fass240us]

Here are a couple of pictures of the current mounting:



And the old mounting:




And my power routing:



The wire is 4-gauge from AutoZone. I plan on putting a breaker in over the winter and maybe a kill switch, as I will have everything out of the car to *finally* paint the interior.

[cazman]

Oh and just cos its 4ga doesnt mean its good, check the number of strands in the cable, It should be stated on the cable when you buy it.
Electricity flows on the outside of the copper, not through its core, so the more strands you have the better conductivity and less loss of ohms across its total length.
The best stuff you can get has horse hair fine strands and millions of them

[Def]

The skin effect is only an issue with AC power transmission, so not a concern in this case. More strands do make it easier to bend the cable though.

[racepar1]

I would use at least a 2ga wire for the ground wire, as for the power wire I run a 2ga. I would think 4ga would be a little too small, but it all depends on the quality and construction of the wire I guess. I am going to re-do my power wires very soon so I will have to look into using a smaller guage wire. As for the mounting I use the passenger's rear seat. The only other place I would consider is the pass rear floor, if I had a smaller battery. Anywhere behind the pass rear seat is simply too high in the chasis.

[ecugrad]

I would use at least a 2ga wire for the ground wire, as for the power wire I run a 2ga. I would think 4ga would be a little too small, but it all depends on the quality and construction of the wire I guess. I am going to re-do my power wires very soon so I will have to look into using a smaller guage wire. As for the mounting I use the passenger's rear seat. The only other place I would consider is the pass rear floor, if I had a smaller battery. Anywhere behind the pass rear seat is simply too high in the chasis.

2ga is overkill IMHO.

Go to a stereo shop and get some good 4ga power wire.

I used to work at a stereo shop and what we called 4ga the Deka guy called 1/0, when when showed him our 1/0, he couldn't believe it.

[racepar1]

Well for the ground wire overkill is a good idea. The cable is so short anyways that it won't really cost you much weight. The only reason why using just above the minimum guage cable, and not overkilling it, is a good idea is because the cable is pretty long and overkilling the cable will add some weight. Really though it is only going to be 5lbs or so added weight even if you go with a 1ga cable. I don't personally have a problem with a little overkill for that little added weight.