Alternator/Battery Going out?

[Anarcy 10+ year member]

Okay here is the situation. I have got a new system installed in my car. Actually just a new amp. 840watts RMS. I have a stock alternator and an about 6 month old Energizer battery. Got a cap installed, fine. The lights were dimming. 2 days later, the lights are dimming like mad. The HU is shutting off if i turn up the volume/bass. Im thinking its alternator. I am only getting 11.5 VOLTS to the amp when the car is on or off. Any one got any ideas if its the alternator or battery? It is having trouble turning over now. NO stereo until I get this fixed, which sucks. Help me out guys, Thanks.

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[tbirdsony 10+ year member]

hey i had the same prob with my car. for me it turn out to be both the battery and the alt. because of the battery getting drained so much the battery was garbage so i put a new battery in that did not fix it the battery kept dieing so i changed me alt to see if that changed anything and it worked. my stock alt it 65 amp i got a custom made 145amp made and i put that it.

so here it what i would do if i was you i would bring the car over to a place that tests batterys and alt for free and get them to test both.

and the cap that you have i had a cap too but i get rid of it because when you think about it yes it gives you a better steady flow of power to the amp but with a stock alt it is just a another thing that it has to recharge. which makes that alt have to work harder. in my opinon if you are getting in to 500W rms or more the best thing to do it is to get a high output alt

peace

AJ

 

[Anarcy 10+ year member]

About how much did that Alt cost you? I am gunna go to pep boys today and get a full electrical check. It costs 20$ but in the long run i think its worth it. My friend has some kind of membership at it, so he gets everything for 60% off. So i was thinking about picking up a 120amp Alt also. I hope that is enough, it should be. My current battery has a 2 yr warranty good thing, my car is barely starting now //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

 

[pavengmike6 10+ year member]

A custom alt is not cheap. You are doing the right thing by getting it checked out. Is 120 amp the biggest they have that will fit your car? I am running 2,500 off a 90 amp alt and no dimming. Granted there is more than just an alt that makes a difference. Will a 1 ga wire fit in that amp? if it would, change your ground to a bigger wire than your power. It is a little know fix to most dimming problems.

 

[Anarcy 10+ year member]

Okay. I just called up Pep Boys. They only have the stock 70amp Alternator. I am running 1100 watts rms speaks, 840 rms brigged amp. If you're saying that your 90 amp alt is convering that many watts.. then im thinking that by getting the 70 amp it might help, i just got a cap put on. I have 4 ga in and out of the amp.