Trunk mounted battery

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Wire

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I had my engine bay painted, looks so nice I want to move my battery to the trunk. Can I just run a positive cable inside my car to my starter and run a cable from the starter to relay and run a ground to the frame of the car? I was thinking of adding a cut off switch near the battery for security protection when the car is parked. I just want clean up the engine bay, I'm not running the car down the race track. I am using a Optima Battery with a hold down battery tray.
 
a cut off switch=yes - even on the street!! I like them because it makes working on things so much easier! *click* power off - *click* power on. I think the rest of it sounds right, buy a kit and follow the directions.
 
No need for a shut off if you aren't going to the strip. Brand new cars such as BMW's that come with the battery in the trunk don't use a shut off... You car doesn't care where the battery is mounted.

You can run the cable inside or outside. I've done it both ways. Ground of course goes to chassis so that's easy.
 
I would not run it inside of the car -- Run it underneath instead. - Just my 2 cents - It's your car.
 
Welding cable from Gebo's or Tractor supply and they also have the ends you need.
 
batt-cuttoff_zps468a9a9f.jpg


Do it right the first time!

This would be NHRA legal with a push switch routed to the outside rear of the car. It kills everything including the alternator, so the only electrical power when the switch is off is in the trunk. It's a nice thing to have anyway, as it allows you to turn power off to the entire car easily for storage or theft protection. And if you ever get the urge to go to the track, you'll need it to pass a safety inspection if they're following NHRA standards.

Here's a list of the parts I used...

cut-off switch
http://www.summitracing.com/parts/mor-74102/overview/

continuous duty relay
http://www.summitracing.com/parts/mor-74107/overview/

relocation kit from summit with hold down and all heavy duty cables. Pretty much everything, I think I bought another short cable for the relay in the engine compartment.
http://www.summitracing.com/parts/sum-g1231-k/overview/

I ran my cables inside, following the stock wire harness routing down the rocker so there was crush protection. Running them outside is no real benefit as long as you have some kind of crush protection on the inside. If the cable goes to ground on the floor board it won't matter if it's inside or out, it will light the interior on fire either way if there's carpet on the top side.
 
Thanks for the help guys. Should I add another cable from the motor to the frame for extra grounding?
 
RPMagoo said:
I would not run it inside of the car -- Run it underneath instead. - Just my 2 cents - It's your car.
Click to expand...

I'd have to agree with this. I've done it both ways. Under the car is just easier.


mguner said:
Welding cable from Gebo's or Tractor supply and they also have the ends you need.
Click to expand...


speaking of TSC. They sell jumper cables that are of the soft, flexible type of wire. just like welding lead. 00 gauge or so. Very heavy. Cheaper than buying the welding cable. Much cheaper but just as good and plenty long. Go check out their jumper cable section.
 
I recently purchased several gallons of the GOOD parts washer solvent there. I might have to shop at tsc more often.
 
Please put a kill switch in. Due to something I did, I almost burned my car to the ground, because I didn't have a kill switch.
 
RPMagoo said:
I would not run it inside of the car -- Run it underneath instead. - Just my 2 cents - It's your car.
Click to expand...

In my opinion it's just as safe and maybe MORE safe to run it right down the factory wiring channel under the sill plate

Wire said:
Thanks for the help guys. Should I add another cable from the motor to the frame for extra grounding?
Click to expand...

The front battery is originally grounded TO THE ENGINE with the largest ground cable, and "jumpered" from either the battery or the engine to the body/ frame with smaller jumpers.

!!YES!! You need a BIG jumper from the engine to the body or else run a separate large gauge ground all the way back to the battery.
 
67Dart273 said:
In my opinion it's just as safe and maybe MORE safe to run it right down the factory wiring channel under the sill plate



The front battery is originally grounded TO THE ENGINE with the largest ground cable, and "jumpered" from either the battery or the engine to the body/ frame with smaller jumpers.

!!YES!! You need a BIG jumper from the engine to the body or else run a separate large gauge ground all the way back to the battery.
Click to expand...

The oracle has spoken!!!

Thanks again Del for helping me make up that diagram. :D :thumbup:
 
Yes, you need a ground wire from engine to frame. It needs to be close to same size as your positive cable. If you have an inadequate engine ground, you can cook things like speedo cable, shift cables, etc. Power will search for a ground.

I run the battery cable inside the car, under the sill plates. Running a kill switch is a good idea.

I build 1/0 battery cable in varying lengths.

STAY AWAY from chinese wire. The wire is not good and insulation is marginal most of the time. I've seen wires labeled as one size with FAT insulation in it and the actual wire inside was 2 sizes smaller. Looked like 8ga outside diameter, wire inside was 12 ga. Buy wire that is manufactured in the US or Canada.
 
Here is an idea for your kill switch. This is mine. I used a flaming river unit. Very high quality and heavy duty.
 

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Thanks for everybody answering. Now its time to start the job, I have some great ideas to work with. Thanks again
 
I would always recommend running a power and ground wire the same size no matter where the battery is, current flows in a path and you don't want to create any resistance. Welding cable is very nice it's flexible and can handle the current loads no problem, just make sure to get an adequate size for the current load you plan on using and length. The longer the run the bigger the wire you need.
 
I'll probably catch grief over this but I ran mine through the passenger rocker panel and rear frame rail
 
67Dart273 said:
In my opinion it's just as safe and maybe MORE safe to run it right down the factory wiring channel under the sill plate



The front battery is originally grounded TO THE ENGINE with the largest ground cable, and "jumpered" from either the battery or the engine to the body/ frame with smaller jumpers.

!!YES!! You need a BIG jumper from the engine to the body or else run a separate large gauge ground all the way back to the battery.
Click to expand...
Agree w/ this and rocodart. I always use marine battery clamps to disable battery power , if need be. Altho it has to be done by hand. lots of body grounds, and a motor plate here, no problems w/ that.
 
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