From the front of the car to the trunk area. 93 240sx hatch.

 

4ga wire should be good. If you were running on 100Amps you could go 19.5 ft.
If you were to use 2ga wire at 100amps you could go 31.5 ft.

 

99civicftw relocated his battery to the trunk and i belive we used 2ga from advanced, but a tad cheaper than what you got it for, over the past 2 months or so there hasnt been a single problem

 

You could easily double the current ratings of that. Wire current capacity is rated by voltage drop and temperature rise, so if the voltage drop is acceptable, the temp rise doesn't matter because the duty cycle is so low in an engine starting application like this. A few seconds of really high current is going to raise the wire temp a bit, but after that you're really not running any current to speak of so the temp will go back down. This is totally different than wiring for things like car audio where the current draw could be fairly continuous and the temp rise would have to be taken into consideration.

 

You ought to be aware of what fuse you should use with your new cabling.

As stated above (which I verified is correct) 4AWG cable is rated at 135A, and 2AWG is rated at 181A.

So, make sure that you use a fused that is rated BELOW the cable rating.

For example, if you use 2AWG cable with a 200A fuse, then you cable insulation could melt before it blows the fuse.

Got it?

 

Without knowing the type of wire, that is arguable. I know these are all rules of thumb though, and are fairly conservative ratings for continuous current.

I'm skeptical that if you can carry 181A continuous through a 2 ga wire and stay within acceptable temp rise limits then you'd melt the insulation before you blew a 200 A fuse.

I know that the specs you listed were for 60 degC ambient with the wire in freeair, so who knows what would happen if the wire was under carpet, etc. This also assumes some unknown wire insulation of which the melt point is obviously unknown. I understand what you're saying though.

The point is that you shouldn't be trying to protect the wire at a greater current than common sense dictates it should be continuously carrying.

 

The chart I use is for relocating batteries using the proper wire. I also use the proper footage for adding power points.

 

Just checked, I have a 100amp fuse.

 

2awg welding cable stupid cheap on ebay