I have moved the battery to the spare tire location. I have shaved door handles, and I was thinking about adding a second battery for a backup. I was going to mount a motorcycle battery next to the main battery to be used solely for the door poppers (if the main goes dead). My questions is, can I wire the grounds of the 2 batteries together, and run a switch and a relay between the positive cables? Therefore I would be able to flip a switch while the car is running and connect the two batteries to charge the motorcycle battery.

What do you guys think? Will this work or should I figure something else out?

Thanks,
-Sean-
-Crushed Blue Steel-

 

Connect the grounds to the chassis. Connect the main battery as you normally would. Get a battery isolator for the spare battery.

Problem solved.

 

Well the second battery is only going to be a small motorcycle battery so I don't know if the isolator will work. Plus that is an extra $70-80.

 

The isolator would work for any size battery but could be considered overkill in this application. The kind of hookup & relay you mention is ok. I would have controlled the relay with an oil pressure switch or something that connects when the engine is running, just for ease of use. I would then use two diodes, one from each battery, to supply the door popper circuit. That way you would get your doors open no matter which battery happened to fail.

 

Oil pressure, tach input, voltage sensing, all are possibilities for triggering the relay for the auxilary battery. Two diodes to the door popper would definitely work and be affordable- I just thought of that as a thing that if someone has to ask then it may be out of their ability to assemble.

 

I know some about electrical, I have already eliminated the ignition switch, and have everything operating on switches. Someone thought it would be cool to steal my keys and GM for whatever reason didn't have the right info to make a new key for me.

My next wiring project is to eliminate all wiring I don't need for engine and interior and fix the crappy harness. Should be a headache. I have eliminated the heat/ac and smog from the engine, and all wires have to be hiddin somewhere in the frame or fenders.

Thanks for the input guys! That helped a lot.

 

I'm not sure how yours is wired exactly- just remember that the wireless reciever, the solenoids/relays, and the poppers themselves ALL have to be wired to the auxilary battery.

 

I forgot about that for a minute. Maybe I won't even bother since you can still open the rear hatch with a key even if the battery is dead. I appreciate the help though guys.