[55nomadmac]

Good morning or evening or whatever your time zone is....

I am relocating the battery (a Optima Red Top) to trunk.
Never done this before so I want to do it right.

Any suggestions applicable to this would be greatly appreciated!!!
For temporary use of the battery (to start car) I have run the heavy gauge (1? 2?)
on right side, under car, on frame. I have 10 gauge wire to HEI Batt I have a 12 gauge wire running back to alternator.

I am in the process of rewiring car with Autowire harness.
It will not need to be NHRA approved set up (he's not going there).

Once again, any help is welcome!

Thanks!
Wayne

P.S. What is pigtail for on positive cable? (See pic)
Can I use this to connect to a BMW type positive terminal under hood?
(in dead batt situations)

 

[Jim Streib]

To size the wire or cables, you need to know what the demands are of the starter and what is the maximum the alternator can put out. You can then use charts found online to know what gauge wire can handle "X" amount of current. If on the chart let's say it shows an 8 gauge or a 6 gauge, go with the larger 6 gauge wire.

As far as other suggestions I have:

Properly secure the battery to the vehicle.

Put the battery in an enclosure that is vented to the exterior of the vehicle.

Add the proper size fuse, fusible links, or circuit breakers on the wire/cables attached to the battery.

Cover all exposed positive terminals/connections.

When passing wires through holes drilled into or when using existing holes in sheet metal, use the proper grommets. If a wire or cable passes over a metal edge, protect it so any vibrations do not have the metal edge cutting or wearing through the insulation and damaging it.

When routing the wires/cables properly secure them and route them away from anything rotating and away from heat sources.

Properly terminate the wire/cable ends and do not use the cheap 99 cent battery terminals that clamp onto bare wire ends.

Properly ground things. All of this stuff works in a loop. Sometimes running dedicated grounds of the proper size from the battery to the engine block and then from either the battery negative to the body of the car or from the engine block to the body of the car can be of benefit.

Do some google searches as you are not the only one wanting to do a trunk mounted battery installation. Some I have seen are real good while other's I wonder how it even works.

By practicing and applying good electrical method's, the better the end results should be.

Jim

 

[Verle]

Alternator should have 10 ga wire.

Battery grounded to frame with proper connection. Frame grounded to engine block with proper connection.
Make sure the cable ends are well done. Crimped may not be sufficient.

 

[Kirk's67SS]

Wayne
here is a previous Thread I had input in
http://www.chevelles.com/forums/27-electrical-wiring/396712-relocating-battery.html
see My Post # 4 + 5 / 6 / 7 / 8

Should help some

 

[Jim Streib]

Alternator should have 10 ga wire.

Battery grounded to frame with proper connection. Frame grounded to engine block with proper connection.
Make sure the cable ends are well done. Crimped may not be sufficient.

My experience is a 10 gauge alternator output wire was used when the battery was up front and the alternator size was anywhere from a 37A to a 63A maximum output. For example on my 68 Chevy II Nova, there is an original 10 gauge wire from the alternator that then goes over a few feet to the battery. In this wire there was also a connection or splice to allow power to also go to a fusible link for the external regulator and then another leg that went to the horn relay buss.

If one has a battery in the trunk, and you are running the alternator output back to the battery, a 10 gauge wire could be marginal as the length has now increased resulting in some additional voltage drop. It might not be of any concern though.

The issue could be is if one has replaced the alternator with something like a 100A or larger output alternator and was required due to additional electronics installed in the vehicle. Then at that point, a 10 gauge wire would not be large enough to go from the output of the alternator all the way back to a trunk mounted battery.

I'll agree too, that a lot of things can be prevented with proper wire terminations and I like too making solid crimp connections and then if the installation allows, soldering things also.

Jim

 

[Verle]

For battery in the trunk, run alternator 10 ga wire to the battery solenoid post with the battery cable.

I would also consider a battery disconnect switch. A high quality source is Mercedes dealerships. All new Mercedes are shipped with a battery disconnect. They are often removed by the dealer who may have a box full with a variety of different cable lengths attached. I have been using one for over ten years with no problems, unlike the cheap versions available at parts stores.