I know some of you out there have 2 batteries one for the car one for the system. I was wondering how you get the altnator to charge both batteries. Do you just splice the wires and run them back? Its not for me but for a friend and I am king of curious myslef.

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Flowmaster,Edelbrock open filliment filter with K&N filter in it
160 stat,

 

The easy way is to just wire the batteries in parallel and watch your alternator die a slow death trying to charge 2 batteries. The better way is to go to a car stereo shop and get a dual battery isolator, but unless you plan on playing your stereo for very long periods of time with the car off, you'll see absolutely no benefit to having 2 batteries.

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Yes, the only purpose of having multiple batteries is so that you can play your radio for a longer amount of time while the engine is off.

You can simply wire the new battery in parallel with the original one, but as Jim said, the alternator will work harder, providing less power for your system.

You could add a dual-battery isolator...keep the original battery hooked up to the engine and other factory stuff, and hook the new battery to your stereo. When you leave the stereo on all night while you're parked, only one battery will run down, and the other one can still start the car.

The bottom line is that the only reason to add a second battery is for more engine-off playing time.

 

i have two batteries wired in parallel with one altenator. it worked great for parties, i would have the stereo(4x6,6x9,2 10's) going for hours. i didn't car about the altenator because it was lifetime at autozone. it finally did die, but it's well worth my time to just switch them out. my friend bought a quality battery isolator and spent $250. it all depends on what you want.

thadd