head unit shuts off after battery died

[Lilni]

two weeks ago the rubber stopper for my brake light switch came off and i unknowingly left my brake lights on overnight, completely discharging my battery. ive charged it once or twice since then but the engine just doesnt start as easily as it did before. even though i drive the car everyday, the battery just doesnt seem to be charging up to full capacity. since all this happened, everytime i turn up my alpine headunit past "20" it shuts off and restarts. ive already searched the forums and apparently alpines will shut themselves off if there isnt enough power or if theres a bad ground. considering my ground has been perfectly adequate up to this point, the stereo must not be getting enough power... im thinking that my 4 year old battery has finally crapped out and the alternator is constantly trying to charge it up, causing the low voltage. anyone think they might know whats happening here?

 

[Defiant]

The load on your alternator trying to revive a dead battery may have been enough to finish it off.

 

[wishgst]

doesn't hurt to take your battery up to an autozone or whatever you have near you and askm to do a test to see if its good. takes them about 5 mins and its free

 

[Lilni]

the radio has stopped shutting off now, im assuming the charge is decent enough now... im going to get a new battery soon because my car still doesnt start quite as well as it did before and i dont want to risk being stranded

 

[quick_dsm]

do what wishgst said. Go to autozone to see if your battery is good. You dont wanna spend cash on a new one if you dont need to. But considering its 4 yrs old.....a new battery isnt a bad idea=)

 

[heckles]

Even if the battery was low the output of the altenator should be enough to operate your radio as well as charge your low battery. Sounds like the altenator is on its way out the door. check the voltage at the battery while its running, should be between 14-14.5 volts. I bet yours is at 13.2 or lower. do the same at the altenator. the difference between the batt and alt volt levels is the charge voltage your losing due to bad connections corrosion and bad wires.

 

[Lilni]

the alternator is less than a year old so it shouldnt be going bad this soon... as of now my stereo has stopped shutting off so i dont know if ill ever figure out what the problem was. next time i get under the car im gonna check the connections at the alternator and everywhere else though. i guess ill just have to play it by year

 

[heckles]

As said before,^^^^ Autozone will test it for free, if you dont have a volt/ohm meter. within the last 3 weeks I watched my altenator die with my volt meter. The first indication was my warning lights fading on while running at low idle, soon after the cd player would shut off and switch to radio. Then to having it die completely. luckily I had a spare off of the original motor.

 

[Lilni]

well, the problem definetly hasnt gone away. ive got about 13.4 volts at the battery at idle and at 2000rpm. i dont know what the hell happened to my volt/ohm meter so i cant check it at the alternator for now, all ive got is my battery charger which reads the volts. im gonna take the alternator out and have it tested whenever i can get a ride. thanks heckles