I just installed a JL stealthbox with a 250RMS watt amp. I have also got a new battery and an alternator at 95,000 miles.

My battery has died twice already with the sub in, and I'm not even using the sub with the car off.

The voltmeter will hover right above the low redline when I use my brights, heater, and 250RMS watt amp, and this is even after driving around.

Wondering why I'm having such a problem with such a small sub.

I'm thinking it's my alternator, but perhaps someone can clear up my situation a bit based on the info.

Would it be a good idea to get a rebuilt stock alternator or buy an aftermarket, stronger alternator?

 

I would say that yea it's your alt. and i would say no about investing in the stronger alt.,with the amp you've got you shouldnt have any probs at all. My car has got a 300 watt amp and a 200 watt amp in it with 4 10's and the lights just barely dimm when it hits but tha gauge doesnt even move. My guess would be that you have probably got sumthin wired up wrong seing as how it is drawing your gauge down and that your bat is goin dead or as i said earlier it is probably your alt.

 

check your ground, for your amp make sure its secure, a loose ground or another connection can cause your bat to drain, also check your bat cables.

 

Definitely have your charging system checked out. A 250W amp should be well within the capablity of your car's charging system. How a loose ground could possibly cause your battery to drain is a mystery to me. If it has a bad ground current won't flow and there can be no drain on the battery. And if the car is off and you have everything wired properly the amp can't draw current then either.

 

if the cable is loose it can ive seen it a few times on different cars from loose battery cables so the battery doesnt charge properly to a loose or bad grounding spot for the amp.

 

The cable actually was loose, I think this was because I covered it with something yesterday. this is after the battery died. when we connected it we did tighten it, even though the ground wire was kinda short.