Trunk Mounted Battery + Rear Firewall - routing battery cables, feedback wanted

[rossmacd]

There are schools of thought regarding battery cable routing, and they usually revolve around a budget. Will running a 4o ground to the engine block impove grounding? Yes. Is it worth the expense? Probably not. I would (and did) just run my ground from the battery to the framerail and call it good. Make sure you have an equally large cable from block to ground, and you are golden. I get 13.3 volts or so, using this method with 2o WELDING cable. Strand count is in the 1300's. That alone was worth 2v over my old Summit 2ga (or whatever) cable. Also, I go all my lugs, and lug covers, from McMaster Carr. Very reasonable prices. They also had solderable lugs, which aleviated the need for a crimp. That, plus adhesive lined heat shrink makes for a great connection. You don't have to worry abot cracking with battery terminals the way you do with smaller (i.e. 12 g) wire. The cable is heavy enough and strong enough that it doesn't really vibrate. You can buy crimpers for like 30 bucks or something that are practically just a punch, but they aren't great. At least that was my experience.

As for the trunk divider, why do you want to run one? Is it to conform to some class rules? If that is the case, you need to find out what they say about things that pass through that firewall. If it is because you want to and you think they are cool, then I wouldn't hesitate to run those bulkhead connectors. But I wouldn't leave a section clean so the cables can run through; one, it defeats the purpose of the firewall, and two, it porvides a point where, theorhetically,the cable could wear.

Alternatively, you could run it through the trunk floor and under the car. But that of course has its own problems.