Battery in trunk

[Aussiemadonmopars]

Ive been looking for threads on relocating the battery into the trunk and haven't found many, maybe I'm not typing in the right words to search for. Is it better to run the cables through the interior or clip it to the chassis rail under the car. I would love to see some photos of what other people have done. Also I would be interested in seeing some hidden wiring jobs too. Thanks guys.

[Ghoste]

I did it in one car years ago and I ran the cable through the interior. 

[myk]

Been thinking about doing that as well, for better weight disribution and all that. I'll be watching this one...

[303 Mopar]

I moved the battery to the trunk of my '71 Challenger, along with the MSD and brake vacuum pump.  I ran the cables through the frame rails, and it was a PITA to get them all the way through.  The MSD and all other wires were ran through a loom out the trunk floor pan, inside the fender wells, along the pinch weld and then through the splash guards into the engine bay.  My objective was to clean up the engine bay and hide as much wiring as possible, a side benefit was weight distribution.

[green69rt]

Ive been looking for threads on relocating the battery into the trunk and haven't found many, maybe I'm not typing in the right words to search for. Is it better to run the cables through the interior or clip it to the chassis rail under the car. I would love to see some photos of what other people have done. Also I would be interested in seeing some hidden wiring jobs too. Thanks guys.

If you do this, make sure you use a larger battery cable than used in front.  Maybe someone on here can make a recommendation or calculation...

[comet_666]

I ran mine through interior under carpet, very simple and untraceable actually. You can buy a relocation kit at Mancini or anywhere else. Have to drill a few holes in trunk and run a vent tube outside but like I said pretty simple.

[John_Kunkel]

Me too, I always run mine through the drivers side wire trough below the sill plates....I use 1/0 welding cable but bigger won't hurt.

There's a lot of disagreement on the common practice of using the frame for the ground with trunk-mounted batteries (the factory does it) but purists believe you should run a full-length ground cable to the engine block....my opinion is that the frame is OK if a smaller gauge (#4) wire is also run full-length.

[Aussiemadonmopars]

I'm still inclined to run the cable inside some mechanical protection barrier if it's going through the interior especially if there is no fuse on the battery.
Hey 303 Mopar, it looks like you have a fuse on the battery there as well correct? What size is it? Or is it just a knife switch?

[303 Mopar]

I'm still inclined to run the cable inside some mechanical protection barrier if it's going through the interior especially if there is no fuse on the battery.
Hey 303 Mopar, it looks like you have a fuse on the battery there as well correct? What size is it? Or is it just a knife switch?

Just a knife switch.  I was not comfortable running the cables through the interior and I wanted them protected which is why I chose the frame rails.  I don't think the Charger rails have as big of curves as my Challenger so it might be easier.  It took me 2 hours to get the cables through the Challenger rails.   

[firefighter3931]

There's a lot of disagreement on the common practice of using the frame for the ground with trunk-mounted batteries (the factory does it) but purists believe you should run a full-length ground cable to the engine block....my opinion is that the frame is OK if a smaller gauge (#4) wire is also run full-length.

John is correct ; if you use the rear frame rail as a ground source you must run and additional ground wire from the engine block to the front frame rail.

Consider this ; the front mounted battery setup has the neg cable bolted directly to the engine. Perfect    Now, relocate the battery and use the chassis as a ground and that causes problems because you're relying on sheet metal to supply an adequate ground source and the rubber motor mounts just won't conduct electricity...rubber is a great insulator but poor conductor.  

On my car I relocated the battery out back and tried to use the rollbar mount as a ground. It should have been more than adequate I reasoned ; rollbar welded to the frame.....subframes tied front to back with welded in frame connectors which were also welded to the rollbar. Perfect...or so I thought. The engine would barely turn over !  

So, I just bit the bullet and ran a #1 welding cable from the negative terminal all the way up to the engine block. Now everything is perfect....turns over just like it did before with the battery up front. Maybe even a bit faster than before  

The rubber engine mounts are the problem in my opinion....hence the need for an additional ground strap from engine to frame. For those without subframe connectors ; you're counting on the car's welded up and thinner guage sheetmetal to provide a path to ground. A continuous length framerail would be a better choice (welded in subframe connectors)  

Based on my experience...the right way to do this is to install a full length cable from the neg terminal to the engine block. Especially if you have no subframe connectors welded in and are using stock style rubber motor mounts.  

Fwiw, the battery should be mounted on the passenger side when trunk mounted to balance out the car and provide additional weight over the side that sees the additional torque during hard launches.  


Ron

[303 Mopar]

Below is the schematic I made when re-wiring my '71 Challenger.  I had a separate ground from the battery negative terminal to the corner trunk floor pan (which was also a ground for the MSD and relay switch for brake vacuum pump), and then ran the battery cable to a ground on the block via the frame rails. 

[rebby]

Here -> https://rebby.com/charger/electric.php#battery is how I went about this several years ago. I can't say for sure if it stood the test of time or not since I took the car apart a few years later. Still working on getting it back together.

[comet_666]

I have frame ties and solid motor mounts so I should be ok?

[myk]

Here -> https://rebby.com/charger/electric.php#battery is how I went about this several years ago. I can't say for sure if it stood the test of time or not since I took the car apart a few years later. Still working on getting it back together.

Nevermind groceries in that set up, lol.  Very informative article, though...

[K9COP]

Guys, I moved my battery to the passenger side of the boot when I rewired the whole car. I did use the inner boot structure as a ground, but ran an earth (ground) strap from the engine to the body under the bonnet too.

I ran my 'hot' wire inside the car, as stated above, under the drivers sill plate, but I actually ran mine up behind the dash to where I mounted a cut off switch actually in the dash, so the red key sticks out of the gauge bezel itself. When I get out of the car, I just turn that switch off, as well as the ignition. From the cut off switch I just went forwards out the firewall to the starter relay. I got spooked when my ammeter blew/smoked which is what caused me to rewire the whole car, so now I have a cut off switch inside the car, which I accept leaves the hot wire, well, hot, up to the dash, but I have a 'blade' type cut off on the positive terminal on the battery too.

I started off with a black plastic battery box in the boot, but that wouldn't work with the mounts supplied so I now have an aluminium box back there.

K9

[HPP]

I'm still inclined to run the cable inside some mechanical protection barrier if it's going through the interior especially if there is no fuse on the battery.

You can do the old ford solenoid trick so the main cable is only hot during cranking.

[rebby]

Here -> https://rebby.com/charger/electric.php#battery is how I went about this several years ago. I can't say for sure if it stood the test of time or not since I took the car apart a few years later. Still working on getting it back together.

Nevermind groceries in that set up, lol.  Very informative article, though...

Which is exactly why I'm abandoning that set up. I need room for the golf clubs!

[c00nhunterjoe]

I have a 31 series agm in the trunk. Pretty sure i ran 0000 wire to the front. All routed inside the car. Have a 00 ground wire from the block to the frame.




Ground can be seen next to the coil and runs up next to the overflow bottle

[1974dodgecharger]

wow how did you run 0000, that's some thick stuff......

[myk]

Here -> https://rebby.com/charger/electric.php#battery is how I went about this several years ago. I can't say for sure if it stood the test of time or not since I took the car apart a few years later. Still working on getting it back together.

Nevermind groceries in that set up, lol.  Very informative article, though...

Which is exactly why I'm abandoning that set up. I need room for the golf clubs!

Ah you're right.  I haul my road bicycle and various other things in the Charger like others would in an SUV.  If I mounted the battery back there that level of utility would be gone.  Back to the drawing board...

[c00nhunterjoe]

wow how did you run 0000, that's some thick stuff......

Headed up tonight to work on the car. I will verify that it is indeed 0000 and get some pictures.

[c00nhunterjoe]

My apologies, it is 00 wire, not 0000. Either way, its huge....lol. and i have never had an issue cranking the ole gal up with near 200 psi cylinder readings.