okay so my car doesn't start when it doesn't want to. sofar this week i needed a jump 2 times. and every other time i've turned it on, all is good. but i noticed...when i turn on the a/c the rpm idle drops, then headlights....rpms drop..radio aswell. i just put in a kenwood 5 channel amp to 4 speakers and a 10inch sub in the back. so i'm thinking it has to do with that but i hear it's not. soooo...could it be my starter or alternator? I took the battery for a test and it's perfect, but something is killing it? until it recharges? i don't know what could this be?

 

It really sounds like the battery is bad, or something is draining it while the car is parked. Is your amp properly wired to shut down when the HU goes off? If the alternator were not charging the battery, the battery will become dead, you can jump start it, but after driving a few miles the car would run out of electricity again and just die.

 

they test the battery after i jumpstart the car and they say it's like a new battery. yeah i think my amp is wired correctly, they have this long dome looking thing next to the batteries positive line. friends of mine who own the place did the installation. what about the idle rpm dropping dramatically? does this happen to your car? i've been tolda few times it could be the alternator.

 

your rpms dropping just means theres a load on the alt.... if your alt was bad it wouldnt do that ....it really sounds like theres a draw on your battery..... if you hook up a multimeter between your battery terminal and the battery there should be less then 0.2 volts of draw....more than that and given enough time youll end up with a dead battery every time

 

damn....so what do i do to fix this? is it the battery then? too much strain on it? i've heard people putting alot more on it theni am.

 

you have to test with the vehicle and the stereo off.... it just lets you know that something is draining the battery.... if theres a draw a new battery will go dead too....... if you have a draw with every thing off start by pulling fuses and watching the meter til it goes away...... iv'e seen a short in a taillight wire kill a battery before