battery moved to trunk on a friend's Dart... wire gauge

[Nacho-RT74]

I'm working on a friend's Dart and he wanted to move the batt to trunk. Locally is imposible try to find "flat" battery wires to run underneath the carpet, so we had to choose one what will be enough for the job but not extremelly thick to go through the cab floor.

we already got 4 gauge... Do you think should be fine that one to drive the load and distance to starter motor or 2 gauge was the right choose and we did it wrong ?

Mopar diagrams show 6 gauge on originals.

[Nacho-RT74]

forgott to say... using a modern Ministarter, not the stock one, so load should be less than the stock

[tan top]

think thicker gauge , as the distance from battery to starter !!

[2Gunz]

According to many wire size charts that's to small.
But I also see many charts with misleading or inaccurate information.

My thought is that in best cause scenario it will be fine and you will have no problems.

But I also think that worse case scenario it will be a problem.

If it where me I would do my best to put it into worst case scenario and see what the results are.


What seems like worse cause scenario to me........

Hot outside         (in general heat is an enemy of electricity)
Engine hot          (A hot starter will use more amperage)
Battery weak       ( lower battery voltage will cause the starter to consume more amperage)
Car not starting    (extended turning the engine over will heat up wires)


If you decide to give it a torture test I would be interested in the results.

Sorry I wish I had a more direct answer.

[elacruze]

This has been in my job jar for a while, since I'm getting battery-in-trunk also.

The question cannot be calculated without knowing the amp draw of the starter on that particular engine.
I remember testing cars in the '70s-80's and seeing as high as 300 amps on a starter circuit. I'm sure that the mini-starter will draw less, and if the engine is reasonably cammed with reasonable compression you won't exceed that.

However, I like to say that fortunately for the world my imagination does not affect reality.

I haven't found an amp table which shows up to 300 amps, but I did find one up to 200A @ 12vdc-
http://eduhosting.org/windpics/wgwire.html

#4/0 cable can carry 200A @ 12vdc for 11 feet within a 2% voltage drop. To me, that means I'll want to use nothing smaller.

Here's a link to installing a trunk battery with NHRA approved disconnect-
http://www.google.com/url?sa=t&source=web&cd=33&ved=0CCYQFjACOB4&url=http%3A%2F%2Fwww.myo-p.com%2FTrunk%2520Mounted%2520Battery.pdf&ei=yVC4TIfiCoL6lweL373qDQ&usg=AFQjCNFTRAU5-BD1zfc1oats08a659Sa0Q&sig2=1a6fe03IFxiMqt4NnnsfVw

[2Gunz]

Nice chart.


Please note that #4 and #4/0   are NOT the same thing.

4/0 is a much heavier gauge.

[Nacho-RT74]

4/0 is a GIANT wire, I have used those and 2/0 on audio and lighting jobs ( concerts )

honestly, the stock starter draws LOT more load, and assembly plant used as wiring diagrams state #6 , true in a 4 times shorter wire. So I increased gauge one step even using a ministarter, thats was my relation to save the distance.

Battery will be 800 amps reserve, 24 group ( I think you reffer to that number spec something like "cranking load" ? )

camshaft is stock, engine is 74 318, but with 302 closed heads

I expect to mount the battery on axle bump area, to save at least one or one and a half meter. Will save some of the trunk "util" space too. Will be around 3 meters or 3.5 in total from starter up to battery.

I hope will be fine, because this wire is EXPENSIVE.

[Highbanked Hauler]

 I am comtemplating the same thing with the battery in the trunk and was thinking of using arc welding cable to the starter.

[Dans 68]

Have any of you done a "Google" search? Try "moving battery to trunk".... Lots of practical information. 

Dan

[elacruze]

Nacho,

You must have the equipment to check the DC Amps the circuit currently (no pun intended) draws?

Considering the duration of cranking, you could probably use 0 or 00 wire.

You could also do a test, just connect your #4 cable to the starter and battery where they are, and loop up your 10-12 feet. You'll know then exactly how it works.

Welding cable is a fine choice, I'll do the same-it's of a much higher quality than battery cable and much more flexible.

[Tilar]

Considering the duration of cranking, you could probably use 0 or 00 wire.

  I think I would definitely go with a 0 or 00. #4 seems a little small going that distance.

[elacruze]

Another option would be to run parallel #4 wire, you can get it in paired length, just like pre-made jumper cables. You'd have additional capacity and less height to conceal. 

[Purple68]

I used 00 welding cable and it was easy to work with and I was able to route it inside the car. Ran the car all this summer...no issues.

[Nacho-RT74]

welding Cable ? never heard about!

more specs... headers, Performer intake, Eddy carb, and MSD, so mostly sure cranking time will be shorter due the MSD

[tan top]

hear welding cable  , is good quality fine strand !!  stuff 

[John_Kunkel]

Most trunk relocation kits (Summit, MP, etc) use 1 gauge wire.