What gauge battery cable from engine bay to trunk?

[kimokalihi]

I would like to free up more space in the engine bay so I plan to relocate my battery to the trunk. Plus I've read that agm batteries don't do well in the heat under the hood.

Is 4 awg wire sufficient or do I need 2 awg? This car does not have and almost positively won't ever have auxilary lighting or car audio except my pioneer premier deck rated at something like 25 watts rms per channel using only the front stock speakers.

Do I run a fuse at the battery since ill be going through the car with this wire and its lengthy, obviously.

Any tips or suggestions would be helpful like what kind of setup to do under the hood to tap into power for things like the horn or jumpstarting the vehicle.

Also, do I need to run a ground all the way to the engine bay or can I just ground it to the body and call it good? Battery cable is expensive.

[Grayguy]

I ran a 2ga power and 4ga negative when I did my first GT. I used a 50 amp fuse right back by the battery. I also grounded the battery 3-4 places in the.trunk and then 3-4 places in the engine bay. I ran a kicker distribution block in the engine bay, it worked really well, I saved everything from this setup and just need to reinstall it in the current GT.





It really freed up a lot of space under the Hood

[kimokalihi]

Thanks for the pics. Why didn't you run at least equal size ground? I guess as long as the ground wire can handle more than the fuse you should be ok but I wouldn't rely on that.

[BoostedSubie]

I used 2 gauge welding cable, it was expensive but the welding cable uses more smaller strands of wire. I based my calculations on 16ft which ended up being about 2 feet too long the way I ran it and even at 16 feet the voltage drop was sufficient so 14ft is even less. A lot of the European cars such as BMW and Mercedes have the battery located in the rear factory and they use 2 or 0. I used some 0 gauge ground cables I had laying around in the trunk to the strut tower and a couple in the engine bay. I found a positive terminal from a BMW I think, that connects the main positive cable with the power wire going to the fuse box and is also used as a jumping terminal, it is all contained in a plastic box that I screwed down next to the fuse box.

[Grayguy]

Thanks for the pics. Why didn't you run at least equal size ground? I guess as long as the ground wire can handle more than the fuse you should be ok but I wouldn't rely on that.

Well a lot of the setups I've seen just run 1 ground to the body in the trunk, so I figured the 4ga grounded 3-4 spots in the trunk and 3-4 spots in the engine bay was more than most people ever considered doing.