Ok, I need to put a 2nd battery in parallel with my main batt. Obviously, I need to put the same exact battery as the 2nd to avoid hosing up my main battery. The question is, even with the same type of battery, will it **** up my alternator and/or main batt? The battery is going to power a sleeping computer when the car is off. I already hooked the sleeping PC up to a battery and it can live for 5 days without the batt draining.

 

just get another battery that has more cca's than the one u have or one thats meant for an application like that. with the way you wouldh have it hooked up, both batteries will be sending current to the comp

 

ok, suggestions on a batter? My current batt has 735 cca's.

 

i would suggest an optima, or something of the like i dont have too much experience with batteries persay. sorry bud, good luck tho

 

good question. From what I've read, and asked from electrical engineers, the answer is no...nothing will mess up. I'm actually going to put together a collection of 12V power supplies together and run a 1000W amplifier off of AC power. I asked the same questions to them, and they said it should run. off of ebay, they have some 12V 13A PS's for $20 a piece. I figure i need 6 of those.

You just have to remember...as 12+ VDC circuit doesn't mean anything till it has somewhere to go(ground). So as long as it's in paralell, it's good.

 

If you wire in a battery isolator between the batteries, then you can have the alternator charge both batteries but only have the car draw from one batt and the computer draw from the other. That way you wont drain your main battery if the computer is left on accidentally.