Join Date: Nov 1999
Location: Central California, USA
Re: Relocate Optima battery into trunk wiring questions
Isn't the way I would do it but it will work. The Optima will not vent unless you charge the devil out of it, like if something went wrong with the alternator and it stuck wide open. It's nice because this battery will not put fumes in the car when it charges under any kind of "normal" conditions.
It's OK to mount an Optima in an open mount, but check the rules if you race your car, some rules want the battery fully enclosed and covered so you can't see the terminals.
I ran one "0" sized cable from battery, to a ford starter solenoid in the trunk, then on to the starter, attached a jumper wire from battery cable to starter "SOL" terminal right at the starter. This way whenever the rear solenoid is energized, the starter runs. The rest of the time the large cable is dead. I use the chassis as a ground, ran the bat neg cable to the rear bumper bolts inside the trunk. An old wife's tale is that the cable must have fine strands like welding cable. I researched this, and it only applies to AC circuits, on DC wire strand count is not important, it just makes the cable more flexible.
I extended the starter sol wire from ign switch to the rear Ford solenoid, an 86 Bronco version mounts in the trunk very well. Ran an 8 ga wire from the horn relay back to the battery to charge it. I put in an inline cut-off switch in this wire to disconnect all power from the car. You can buy a 50 amp toggle switch at most parts stores, it's just slightly larger than a regular toggle switch and it can handle charging loads well enough. I ran a small fused line direct from Bat + to the radio to keep the memory and clock going. You don't need the huge tractor cutoff switches because starter loads are not carried by the toggle switch, just charging and running stuff when the engine is off. Madd says an 8 ga wire is sufficient.
I would add a relay to break the alternator energizing circuit if you want the rear switch to cut off the engine while it's running. I think if you use the relay you would have to use a double pole single throw 50A Cut-off switch, so you don't get feedback from the alternator.
Check my web page for First Gen Camaro suspension info:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
67 RS 327 original owner. 1965 Lola T-70
Last edited by davidpozzi; Mar 28th, 10 at 11:07 PM.