I have a big system in my car and I want to run an auxilary battery that would get charged by the alternator but would be isolated from the main battery (not connected to it).

I am not exactly sure how to do this but I think I am supposed to connect the ground going to the main battery to the backup battery. Am I right or is there another way of hooking this up?

This probably isn't the correct place to post this but this section gets the most exposure to the public. Can anybody help?

 

if it's part of the charging circuit, it's part of the circuit....

What exactly are you trying to accomplish with the 2nd battery?

 

I want to have an extra battery that will only power my amplifiers and will not drain power from the battery that starts the car but I also want this extra battery to be charged by the alternator.

 

So you have issues with your accesories(power windows, lights...) while your system is drawing power? Or do you want to play your system for extended periods of time with your car off?

 

Put a relay inbetween the alternator and the 2nd battery that is triggered by a switched source off the ignition. While the car is running, the relay will close and it will be one combined circuit (and thus get charged and when the car is off, the relay will open and disconnect the two circuits leaving you to drain the 2nd battery.

 

battrey isolator or diode

 

yup.

 

instead of running a battery cable all the way from the hood to the trunk, y dont you just ground out the extra bettery to the body? find a good sized bolt, get some sandpaper, and ground out somewhere to the trunk to complete the circuit. and invest in fuses.... fuses are always a good thing

china

 

Auxilary battey is a good thing but are you even running a top notch Optima battery now or just a regular one. I bought an optima red top and i can run my 1600W SPL amp for a while with the car off and still have enough juice to start the car.

 

yeah because its not 1600w at a constant rate