Battery Relocation To Trunk

[70RT4SPD]

Has anyone mounted their battery in the trunk? I bought a kit from Summit to do just that in our Challenger. Where did you route the cables? Will 1 Ga wire be sufficient or go bigger like 2-O? Kill switch mounting position? Where are your grounds mounted? Thanks in advance!

 

[Xcudame]

You run the positive cable along the left side of the car like the rest of the taillight wiring. The negative side is bolted to the body! the body becomes the ground! You will need a good sized cable from the body to the engine. Go big on the positive cable. Remember, the smaller the number, the bigger the wire diameter! 1 gauge is bigger than 2 gauge. Perhaps you're meaning double aught - 00? 4 gauge or bigger should be fine. For a race car, the kill switch must be outside (rear panel). For a street car you can put it in the trunk or not have one at all!

 

[Bret Schneider]

I know you've already bought the parts, but you might want to check this link out since there's a lot of useful information on it related to battery relocation and all things electrical for that matter. I've bought a lot of stuff from them and have always been happy with the quality of the parts as well as the service.

Battery Relocation Kits

There's also a really good article that talks about grounding when relocating the battery. They make a point of advocating using the body as the main ground in a unibody car vs running a separate ground.

Getting Grounded

One thing you might need to consider though if you're running some sort of EFI set-up is you will need to run a separate ground to the battery from the control unit as just a body ground would be too noisy.

 

[One of few]

I relocated mine, and kinda wish I would have left it in the front. Those are some big cables on that battery.

 

[Chryco Psycho]

I use welding cable , very flexable & heavily insulated .
I always run the neg cable up to the trans so the engine is the main ground rather than connect to the body with the main cable , I still use a lighter cable from the engine to the body . I route the positive cable through the rocker with the other body wiring & connect to the starter .

 

[Tig]

Pretty much done what the others have done. Running a separate neutral wire from the battery to the engine made a real big difference to how fast the starter turns. A 50 year old unibody isn't the best option for use as a ground.
I also picked up a couple of tips from some high end race cars. Like a neutral ring, smoothing / filter cap on ignition system supply, earthing the heads to the block and flywheel diodes on all the relay coils.
I have a Data logger and I have no issues with RFI.

 

[Xcudame]

I don't own a late model Challenger or Charger, but the wife's 2014 Chrysler 300C hemi has the battery in the trunk. So I assume the Challenger and Charger are too! It just makes sense to put it back there on the passenger side. The whole weight transfer thing!

 

[heminut]

I don't own a late model Challenger or Charger, but the wife's 2014 Chrysler 300C hemi has the battery in the trunk. So I assume the Challenger and Charger are too! It just makes sense to put it back there on the passenger side. The whole weight transfer thing!

Wife's 2020 Challenger is in the trunk on the right side.

 

[70RT4SPD]

You run the positive cable along the left side of the car like the rest of the taillight wiring. The negative side is bolted to the body! the body becomes the ground! You will need a good sized cable from the body to the engine. Go big on the positive cable. Remember, the smaller the number, the bigger the wire diameter! 1 gauge is bigger than 2 gauge. Perhaps you're meaning double aught - 00? 4 gauge or bigger should be fine. For a race car, the kill switch must be outside (rear panel). For a street car you can put it in the trunk or not have one at all!

This is what I was thinking. I’d like to go with 2 aught but that wire is huge and I figure would be hard to tuck into the wire channels on the inside of the car. 1 gauge looks like it would be the best fit but I wasn’t sure if that would be too much load due to the length it is running from the trunk to the starter. I don’t want to run them outside the car because this is a street car and just asking for problems doing that.

 

[70RT4SPD]

Pretty much done what the others have done. Running a separate neutral wire from the battery to the engine made a real big difference to how fast the starter turns. A 50 year old unibody isn't the best option for use as a ground.
I also picked up a couple of tips from some high end race cars. Like a neutral ring, smoothing / filter cap on ignition system supply, earthing the heads to the block and flywheel diodes on all the relay coils.
I have a Data logger and I have no issues with RFI.

Very good tips thank you!

 

[70RT4SPD]

I use welding cable , very flexable & heavily insulated .
I always run the neg cable up to the trans so the engine is the main ground rather than connect to the body with the main cable , I still use a lighter cable from the engine to the body . I route the positive cable through the rocker with the other body wiring & connect to the starter .

I would definitely run the main up to the engine. How well does welding cable fit on the rocker channel with the rest of the wiring? Did you put both on the driver side? Thanks for the pics!

 

[Chryco Psycho]

It will fit in the rocker ok , , I went under the seat & cut a small hole in the floor & attach to the trans

 

[Ricks72Chlgr440]

A little off topic, but is there any REAL benefit to improve the traction by moving the battery to the trunk on a street driven car? I know my 2021 Challenger has it in the trunk but that may be just to give more room in the engine compartment for all the stuff it has there.

 

[Xcudame]

Ideally you want 25% of the vehicle weight on each tire of the car. Rear wheel drive V8 cars of the 60s and 70s are notoriously nose heavy and mother Chrysler saddle us with a heavy lead battery on the front left corner! Moving that hunk of weight to the rear behind the passenger wheel in the trunk really puts more weight on that right rear wheel and takes it off the left front which with a single driver has the most weight stock.

Would most people notice with normal everyday driving? Probably not, but it sure helps in higher speed handling situations!

 

[70RT4SPD]

If I’m not mistaken the early 60s super stock cars came this way for this exact reason but in my case I think it just looks cleaner in the trunk and cleans up the engine bay some! I planned on buying an Optima gel cell battery as well to put in the shiny new battery box. Also, it doesn’t have to be vented resulting in another hole drilled in the trunk floor

 

[Ricks72Chlgr440]

If I’m not mistaken the early 60s super stock cars came this way for this exact reason but in my case I think it just looks cleaner in the trunk and cleans up the engine bay some! I planned on buying an Optima gel cell battery as well to put in the shiny new battery box. Also, it doesn’t have to be vented resulting in another hole drilled in the trunk floor

Thanks. Am considering it but there seems to be a lot involved. The kit noted above seems good but unless I missed it I don't see a (Ford) relay that some use to keep the long + cable from being hot all the time. Also, since I use electric fans that have a pretty high power draw, not sure it would be a good fit. Still researching....

 

[Cuda Hunter]

Only picture I could find of what I have in my trunk.

 

[Tig]

Thanks. Am considering it but there seems to be a lot involved. The kit noted above seems good but unless I missed it I don't see a (Ford) relay that some use to keep the long + cable from being hot all the time. Also, since I use electric fans that have a pretty high power draw, not sure it would be a good fit. Still researching....

You are going to need a decent sized cable for a permanent feed if you have stuff like an electric water pump, fans etc. I just ran a large cable to a big bulkhead electrical connector on the firewall and used that as a supply point. I put fuses in at the battery ends as close to the battery as possible. Ignition system (MSD) feed comes straight from the batteries (after the fuse). I use 2 batteries in the trunk and a 105A alternator. With everything on, lights, fans, w/p, f/p, logger and running, it takes well over 90A, I'm thinking of switching to LED headlights. The fans alone take over 25A on steady state, more when they start up.

 

[HPP]

What are you hoping to achieve by relocation? If less weight on the nose, you can get a 15# Braille battery that has as many cranking amps as a group 24 without all the hassle of moving. If you want better weight distribution, see previous. Moving the battery nets less than a 1% improvement in weight distribution. If you simply want to clean up the engine bay, okay, but don't forget you need to mount all that wire in a manner that does not contribute to any insulation damage that introduces any arcing opportunity with 20 some feet of live wire
.

Additionally, if you ever take your car to the track with a rear mounted battery without the associated isolation and cut off ability, it will fail tech and you won't get to run. If bracket runs are ever on your radar, read up on the requirements that NHRA is going to be looking for when you show up.

 

[CBCM 1942]

Here is some pictures of the install on my 1971 Challenger with a 1 wire alternator.