Is it my alternator or my battery? Whats going on!?

[RasPlasch]

I have a 1999 Chrysler 300M.. and 6 months ago I put in Alpine Type-R speakers in the back, Alpine Type-S in the front with tweeters, two 12 inch Alpine Type-R subs and 2 amps... the amps together put out about 1500 watts... I know one is 750 watts and the other I can't remember if it is 500 watts or 750 as well... I wish I remembered.

But since I installed all of that.. my lights dim whenever I play the system at a reasonable level. I have also put in a 2 farad capacitor which is capable of handling systems up to 2000 watts. And yes I know capacitors aren't a savior when it comes to preventing the lights from dimming. (figured that out the hard way).

I have the stock alternator still in the car and a basic middle of the road battery in it as well. Lately the car has been slow to start... When I turn the ignition it seems as if the battery is dead almost... but then again other times it starts perfectly.. I went to O'reilleys today to test my alternator and he said it was doing just fine.. then I went to my girlfriends house and her dad tested it as well... and it was running perfectly at 13.8-14.0 volts with the air and radio running while revving at 2,000 rpms.

I'm so confused here... because the car seems to not want to start...I mean it starts but sometimes its so slow to start it worries me... I tried charging the battery and it was fully charged... and 2 alternator tests have told me that the alternator hasn't been affected at all... but the lights still dim when I bump the system loud.

Do I need a top of the line battery? Or just a top of the line alternator? Or do I need both? How has 6 months of use of this system not affected my battery or alternator? Whats going on here? If I do need a new battery or alternator... then how do I figure out what will be a perfect fit for my particular setup?

Any help or recommendations would be fantastic.

Thanks guys/gals.

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[LosIsATool 5,000+ posts]

Drop the cap.. They do more harm then good.. Get a yellow top or equivilant. and add a small battery in the trunk.

 

[mylows10 5,000+ posts]

sounds like when you bump ur system its draining the battery as it does in my tahoe,the cap only helps to assist the battery when the amp needs a steady power supply,but ive found that they dont work as good as you might think.i would try changing ur battery to a better one,prolly a stinger or xs power,most new cars electrical systems arent made to handle larger stereo systems ,so do the big 3 change to a better battery and see how that works for you

 

[IonRL205 10+ year member]

Do the big 3 and upgrade your stock battery and see if you still have light dimming. If you do then add a second battery.

 

[ahole-ic]

Drop the cap.. They do more harm then good.. Get a yellow top or equivilant. and add a small battery in the trunk.

Please explain how caps do more harm than good.

 

[CHEMMINS 10+ year member]

No this isn't a cap conversation....leave that for a dedicated cap thread.

OP....if your car is charging 13.5+ with the system playing and air conditioning on, it is your batt.

 

[Germ305 10+ year member]

Anybody ever think just slightly it could be the starter? or perhaps a fuel pump issue?....Just throwing that out there as far the hard to start sometimes issue.

 

[MoZ 10+ year member]

Anybody ever think just slightly it could be the starter? or perhaps a fuel pump issue?....Just throwing that out there as far the hard to start sometimes issue.

I agree with the German dude. But that doesn't help the dimming so I suggest the big 3 to start.

 

[RasPlasch]

Anybody ever think just slightly it could be the starter? or perhaps a fuel pump issue?....Just throwing that out there as far the hard to start sometimes issue.

I actually thought about this as well.. I was thinking maybe its the ignition or something..

But last night my girlfriends father took out my battery completely and cleaned the corrosion. It has not been starting as slow now.

What battery do I need to handle this system?

 

[05fronty 5,000+ posts]

too me sounds like a weak battery. take it to oreillys or such and have them test it. like said above do big 3, get a new batt up front and add another in back

 

[-01limited- 10+ year member]

Def sounds like your battery is about to go

 

[audioholic 5,000+ posts]

Assuming its not a sealed type battery, as most standard car batts are not, have you checked to make sure all the cells are full of water/acid? A batt with a cell or two going dry will add erratic much like what you describe.

I also agree that doing the big 3 should be done. And with the money you make from selling that cap, buy a nice little voltage gauge you can mount somewhere that you can see from the driver's seat.

 

[RasPlasch]

So..... I installed a new battery.. I went and bought an Optima battery for $200. My car starts now.. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif and the subs/speakers sound even louder now. But the lights still flicker but not as much. And the headlights don't flicker... just the inside lights. Hmm.. and sorry I just couldn't get myself to shell out $200 for a battery and another $300 to get it installed in my trunk.

Is an alternator next? And if so my system is at about 1500 watts... so I'm looking at a 160amp alternator? Or would 130 suffice?

 

[RasPlasch]

Going to buy the alternator now...

bump

 

[audioholic 5,000+ posts]

A 1500 watt system can draw well over 100 amps by itself, so Id get the 160. But there are a lot of factors Im having to ignore to make the generalization.