So I'm planning my battery relocation to the trunk on the passenger side. The car is a '66 Dart.

Anybody have a suggested route to run the +12v cable? I was thinking of coupling it with the tail light cables (along the underside of the car on the driver's side). There are some clips that hold the tail light cables tucked up behind a small lip so there would be a bit of protection.

Would I do better to route the cable under the carpet in the cab? Any other considerations while planning my route?

Why relocate the battery at all?

No I would not run that cable through the cabin. That conductor needs to be exposed to cool air in case it over heats, and not under a carpet pad. Also, too much of a chance for water to enter soaking the carpet pad where it passes through the floor & fire wall.

Additionally battery should be housed in a ventilated box when located in the trunk, all of which has to be bolted down.

Now if this is a stripped out race car, go for it.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I eventually will want more room under the hood for various reasons. Also, on more than one occasion I've had a battery stolen out of my car, at least if its in the trunk its a bit harder And I plan to add a power amp in my trunk and the added connivence of the battery sitting right next to it is too tempting.

Thanks for the insight, I got caught up in protecting the cable and didn't think about cooling.

About battery ventilation boxes... what about sealed batteries (Optima, DieHard Platinum, etc)? Aren't sealed batteries often mounted on the inside of the cabin on some cars? I appreciate the concern of hydrogen gasses in my trunk, but are they really a concern with a completely sealed battery?

Errr - power cable in the passenger compartment is perfectly acceptable and is done routinely on even street driven cars. If the cable gets wet its not really harmful... its fully encased in insulation that I hope is waterproof! The only place you need to worry about water is at the ends of the cable, and if you use heatshrink that won't matter either.

If your cable is overheating the installation isn't proper. The cable may be too skinny for the length & current draw. Or perhaps improperly fused. Power cables shouldn't be getting warm to the touch, otherwise there will be a measurable loss of volts across it.

If your really that worried, it doesn't have to go under carpet. poke a hole in the firewall, run it under the dash to the kick panel, then down to the area behind the sill plate (there is a metal flap the factory tucks the tail light harness under, at least in my duster) behind the back seat then to the trunk.

If not in the cabin then where, under the cabin? That would certainly require some sort of conduit (not for weather related protection but rather projectile protection) and creates a PITA install ....

My taillights run under the cabin along a mostly protected area behind a tab. It seems that it would have to be a small object and a lot of bad luck to hit the wire in this location, but that doesn't mean I'm not a little paranoid...

As I've been reading about others who have relocated their batteries, I've realized it would be good to include a circuit breaker. I was thinking about going with a 150 amp breaker. Should I go bigger? Can anybody recommend an appropriate breaker (links appreciated)?

I'd have a smaller gauge wire for the normal running and use a remote starter solenoid on the large gauge starter wire at the battery so the large gauge wire only has power when starting............

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Thanks Ed, that is some great advice and I would have never thought of that. However, I just finished the relocation a few hours ago, but that doesn't mean I can't upgrade it a bit later

For anybody interested...
I ended up running about 15 ft of 2-gauge cable from the trunk (just behind the right side of the back seat) down the sill channel on the driver's side and into the engine compartment and to the starter. And about 6-8 inches of 6-gauge wire from the starter to the ignition switch. I also replaced my old battery ground with 19 inches of 4-gauge from the motor mount bracket (where it bolts to the engine block) to the fender using a hole and bolt from the old battery tray.

Anyway, I now have a lot more extra room under the hood

let us know how it ends up working out for you.

my only concern is that your car is a unibody
and your making the negative side of the battery ground far away from the engine - but theoreticly if all your grounds are good it should work ok but I suspect that you might have to end up using a 4 guage negative ground wire from the engine block all the way back to your battery in the trunk - if you find that your having grounding problems.


in my car I have added "the big 3"
wich is car audio terms of using verry large wire to go from:
battery - to engine block - 2 guage or bigger
battery - to frame of car - 2 guage or bigger
battery + to charge terminal on the alternator. - 4 guage or bigger with an apropriate size fuze in the wire to prevent electrical meltdown incase the voltage regulator malfunctions.

before I did this in my car - I had verry poor headlight shine and all other electrical items were suffering from poor ground in my car.

my next to do list will be 4 guage wire going from front subframe to rear subframe to allow good conductivity between both of them for my car stereo amplafiers that are mounted back there.

maby its just my 4 door valiant but the boddy structure it self is a verry poor ground circut to the negative at the battery.

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1972 Plymouth Valiant / slant 6 auto

Hey Brian,

It seems to be working rather well. Started a road trip today from LA going up north. Today I'm in Sacramento and didn't notice any issues with poor grounding. I have 2 gauge going from the battery to a sanded area on the body. And another ground (4 gauge) under the original battery tray to the engine block. I'll post any issues if I encounter them.

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'66 Dodge Dart

It sounds to me like you have it covered well. I have had my battery in the trunk for about 4 years with no problems. I ran the positive cable under the cover beside the passenger's sill and ended it at a bulkhead terminal right beside the accelerator pedal. I then ran a short cable from the other side of that bulkhead connector to the starter motor. I ran the ground cable from the battery to the trunk latch bolt. I also ran the original ground cable form the engine to the radiator core support. It has been absolutely fine.

You will lose voltage through those old bulkhead connectors. I bypassed the heavy current leads in the bulkhead connectors years ago and wired the car more like a modern auto with relays and fuses under the hood.

Sam

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Jim
Welcome to the site and Thanks for the Manufactures perspective.
I certainly agree.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

I must say, I'm rather impressed by Optima responding to this post, and with some great information.

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'66 Dodge Dart

OptimaJim,

Thanks for your post. I have run Optima batteries in all my MOPARs for many years. I have been contemplating moving the battery to the trunk in my 74 Dart Swinger. I did not realize that we needed to vent the OPTIMA style battery. Will a traditional downward vertical type vent be fine? or does the box have to be sealed with a horizontal vent? or do you have a particular vent kit that we should be using?

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Thanks for the welcome guys, I’m happy to offer assistance where I can. Ted, we don’t have a specific vent kit that we recommend, but either venting configuration will work for the batteries listed above.

Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.facebook.com/optimabatteries