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Trunk mounted battery

PostPosted: 24 Dec 2001 13:58
by johnny-d
I have not yet moved my battery to the trunk, although I believe I have all the necessary components to do so. Can someone who has completed a battery trunk relocation please explain the process and any safety precautions I should be aware of (particularly any venting issues I may encounter). The car is also being set up with a trunk mounted fuel cell. Thanks

Trunk mounted battery

PostPosted: 27 Dec 2001 11:18
by dave-r
I understand the safe way to do this is to have a fuse in series with the live cable as close to the battery as posible. That way if you have a short circuit in the live lead somewhere along it's length your car will not burst into flames.
To stop the fuse blowing while cranking the engine you can wire in a started relay to by-pass the fuse while cranking.

Use the fattest cable you can get for the run from the battery positive to the starter motor.

Run it directly to the starter motor.

I don't like the idea of a trunk mounted fuel cell. Make sure there are absolutely no fuel vapours venting into the trunk area. If it smells of fuel in the trunk one spark could give you a very bad day.

A plastic marine type box for the battery vented to the outside is a good idea too along with quick-disconnect terminals or a switch.

I of course have done non of these things!

Trunk mounted battery

PostPosted: 27 Dec 2001 17:01
by Blue
Dave, I've located many a battery to the trunk!Use fine strand welding cable, it's very flexible and has much less resistance than that horrible stiff black stuff that motor factors usually sell. B.O.C cylinder center's should sell it by the foot,go for about 500amp rating. I run the cable inside the car and pretty much follow the main harness as it run's along the rocker panel.Use large grommets when going through a panel and cable tie securely to the loom.Crimp and solder the terminals to the cable and cover with heat shrink. I always use sealed for life batteries.Fit a steel or ally bulkhead behind your back seat and seal all edges and gaps with seam sealer. Run a vent line from your fuel cell out through the floor to underneath the car, seal it at the floor with a grommet.Run an earth wire from one of the bolts on the filler ring on the cell to a suitable location. Use another length of welding cable as your engine earth strap. Use a good quality cutoff switch on the earth side in the boot. I usually bolt the main earth lead to the rear chassis leg or where the bumper bracket mounts to the body. Treat yourself to a mopar performance "Mini starter", These things are fantatasic,half the weight, half the size, and they crank the motor over like it's got no plug's in! Happy relocating!

Trunk mounted battery

PostPosted: 27 Dec 2001 17:45
by dave-r
Thanks for that Blue. Image

Trunk mounted battery

PostPosted: 27 Dec 2001 19:39
by Johnny-d
Many Thanks for the advice and directions!

Trunk mounted battery

PostPosted: 09 May 2002 15:38
by LITEMUP (Von)
allong those lines...I have a trunk mounted battery; If I run at fastest a 12 second 1/4 mile time will the track make me have a cut off switch out side the car? how can I get around it? Because I'm NOT drilling a hole between my tailights to do so. I am preparing to go to the Mopar Nationals in August and need to know. thanks

Trunk mounted battery

PostPosted: 09 May 2002 18:21
by Dave-R (Roppa440)
You have to find out what the rules are at the tracks you want to race on. Normally you have different rules for different race classes. Just phone them up.

Most 'Nats' type events run as a 'Run What You Brung' event which normally has VERY loose rules. The RWYB events in Britain only require that you have a full driving licence, a helmet, a radiator catch can, a sound car (not dropping to bits with rust) and nothing dripping onto the track.

Trunk mounted battery

PostPosted: 09 May 2002 23:41
by Rob (Racer413)
NHRA general rules require the shut off switch if the battery is in the trunk. My car runs 12's, the battery is in the trunk and I have the switch.The first time I ran the car I did not have the switch and was told to have it next time.This was at a small time local track.At Englishtown for the Mopar Atlantic Nats, when they looked under the hood and didn't see the battery they went right to the trunk to check the mounting of the battery(3/8 rod thruogh the floor).

Trunk mounted battery

PostPosted: 10 May 2002 7:51
by Dave-R (Roppa440)
But those rules would only apply to NHRA events yes?

Trunk mounted battery

PostPosted: 10 May 2002 15:48
by Ted S (Teds)
no, any time you run on a NHRA sanctioned track.

Trunk mounted battery

PostPosted: 10 May 2002 16:56
by Dave-R (Roppa440)
Bummer. I knew there had to be an advantage somewhere to living in my country.