Battery or alternator

[Lf Lion]

I have a 2005 st and my battery light came on and turns off I took it to the dealership and they told me that I needed a bigger battery cuz I have a nology ignition and aftermarket hids. So I bought a optima battery and I still have a battery light on. Any help would be grateful. Car is still under warranty.

[Sponsor]

[SVT_Freak11]

could be a bad connection, could be a blown rectifier on the alternator if with the mods you have were bringing the battery level down and the alternator was trying to recharge your battery rather than maintain it. an alternator is only designed to safely charge at 2/3's of it's rated output over extended periods of time so if it was operating at full output over prolonged periods of time it could have vary well done permanent damage to the alternator. only way to find out is to have the alternator checked to see if it is performing within specs.

[whynotthinkwhynot]

I agree with SVT_freak about testing the alternator and it wouldn't hurt to do a voltage test on the battery. Neither of the mods you have done should've adversely affected your battery. HID lights use less wattage than the stock halogens, and the Noxology wires are merely spark plug wires with inline capacitors to boost voltage output but would use no more input power than the stock version- or at least not enough to run down your battery. The only thing that I would check for power loss is the Noxology install.. but look at the power input wiring where you moved the coil on plug coils over to the firewall to insure that the power supply wires are not touching metal somewhere with like one stray strand which would use power but not enough to blow a fuse. I'd inspect that installation carefully before trying anything else.

From experience I can assure you that a large percentage of my problems with vehicles resulted from something I had done to the car recently.

[Lf Lion]

thanks Ill check out to see if the wires are touching anywhere. Never thought about that. Thanks Guys

[W~Phoenix~{RC}]

Perhaps there is a loose connection at the battery. Be certain that the terminal connectors are very snug. Once I was having a several electrical problems and I thought the alternator was going bad, but I checked the battery terminal connections and they were indeed loose. After I snugged them up, all of the problems I had stopped. Also make sure that no screws or connections are loose where the alternator is.

Cheers!

[SVT_Freak11]

another good point from wphoenix. remember too that the bad connection isn't always at the battery. check your connections at the alternator as well. Not to mention that in an electrical system, a good ground is just as important as a good power source. make sure wherever you are grounding at is clean and tight as well...

[jaimz]

i had this problem, i foud out my alternator was bad, of course a dealership will tell you something that they don't have to spend money on.

i'd get your alternator check at an autozone or something, or you may find your self in the same place i did, onthe side of the road with a dead battery and dead alternator

[Lf Lion]

I know I took it to the dealer and they said that I needed a biggggger battery. So I bought an optima and I still have that problem

[W~Phoenix~{RC}]

Have you tried hooking up a multimeter yet? Give that a shot and make sure that you are in the 14v - 14.7v range when the car is turned on. If it's any lower than that and all of your connections are fine, then I'd say that your alternator needs to be replaced. Also when your car is off, the range should be 12v - 12.6v. You should check your cables and connectors for any corrosion and make sure that your ground points are secure and clean.

Cheers!

[Blurvfocus]

Real easy way to test this- Wait until nightfall, then go out and start the car ant turn on the lights. Now shut the car off; the lights should dim a little. If not, the alternator is probably not working. Either way, don't forget to check for a slipping belt- They don't ALWAYS squeek when they slip.