Again, if the alternator he is using is not overcharging the single battery, how do you presume that it is going to overcharge upon the introduction of addition capacity?

 

Hmmmmm. Epon, I am guessing you had a normal 12V battery to begin with and added a second 12V. Did you connect the batteries in series or in parallel? If you connect two 12V batteries in parallel, you would achieve your 12V desire, but you will double your current, depending on the battery's previous current, say 650A, it would jump to 1,300A. If you set them up in series, you would get a total of 24V, but end up with about the same Amps. This means you were pumping out way more amps then needed and this probably caused a slow reaction to the insulation of the wires. Also if you put the wires through the firewall, I would check whether you put a grommet in or not. I had the same problem and it turned out to be both problems. Too many amps coupled with my shotty wiring caused a massive engine compartment fire in my '78 Grand Prix when the heat weakened insulation caused by the high amps finally cut away due to the firewall metal. I may be dead wrong, but that is what happened to me.

 

i have the same question as Velvet Leopard. Did you connect the batteries in series or parrell. The batteries connected in series would present some serious problems. and you would be running 24 volts instead of 12. or whatever you have running may be pulling too many amps through the wires causing them to be hotter than lava. and would melt right through the rubber. i would add the amperage on each device your running as the Load and or get thicker wires that can handle that many amps. provided you are running the batteries parallel!

 

No, I wired the batteries correctly so I was still at 12V, don't worry. :P

I know I was pulling a ****load more Amps now, but I needed it because of the setup I'm doing (explained above).

I'm gonna go out and say that it was caused by the guaging of the wires being too insignificant. I'll figure out how many Amps I'm drawing and buy a proper fuse. Should I still get an isolator tho? Seems like a good idea.

Also, can one of you point me in the right direction for a relay... again, I dunno how many amps im pulling, but i have a 200 Watt DC/AC inverter hooked up.

 

Heavy gauge wire is always a good idea when running lots of amps. Ask any 150+ decible car audio fan. As for the isolator, I am kind of embarassed to say I am not sure what that is, but I would think any additional protection is worth it in such a complex and expensive circuit. It isn't hard to make your own custom fuse block, time consuming, but not hard. Just know what all your wires go to. Your two batteries should be acting, and seen, as one battery if you have them in parallel, so you need not isolate anything, if that is what the isolator does. But what I would do is add in some sort of in-line fuse like if you had a massive sound system. That way if your circuit does happens to go off again, only the fuse will burn and not your dash. Oh yes! I forgot another thing. Someone asked how long the wire from the second battery was. Rule of thumb says the longer the wire, the more resistance the wire has. The gauge of the wire doesn't really effect the resistance. Remember, parallel batteries add the amps and the loner wires make more resistance. Add these two conditions up and you get many amps, much resistance equals very hot wires. If you absolutely have to have these two batteries, at least put them both in the trunk or under the vehicle in a proper enclosure. That way you lessen the amount of "loaded" cable. Then simply obtain the correct gauge wire for the amps. Go to any good car audio joint and the installer should be able to tell you the right gauge and connectors to use with each varying wire length and amperage. I hope I helped you out there. I watched a super sweet Chevy 4 X 4 fry on the side of the road due to the driver's added audio system without upgrading the wiring.