Two batteries for car subwoofer?

Question

I have 2 batteries in my old car to power my sub. The car battery powers it when i drive and i have an aux. battery when tailgating because my car is old. Can i splice both neg. together and have the positives w/ switches or will the alternator go to both batteries?

Answer 1

yep...do it all the time...connect the +'s of the batteries together and ground them both (don't have to be at the same location)

Answer 2

your gonna shorten the life of that alternator pretty quick..

but yeah its possible...dont splice the grounds together...run two seperate grounds. and yeah you could run alternator output to both batterys.

i dont know how well this is gonna work..why dont u just connect a jumper box to your battery with a full charge in it...should last you your whole night of tailgating and when you get home just plug the box in