Battery light problem?

[illuzionx]

Hello, i have a slight problem.

During the past couple of weeks ive noticed that the battery light has been occasionally coming on and off randomly.

i have been trying to find what would make it light up just incase its something loose (probably not the smartest idea)eg. accellarating hard, speed bumps, hard breaking, cornering hard etc. note: i may be young, but im not a hoon, i did this soely to test if it will make the light turn on when its off, or turn the light off when its on.

ive also noticed that at night, when the battery lights turn on, my headlights are a bit dimmer :S quite scary actually.

had the battery replaced and the alternator checked and the guy says that the battery is charging correctly.

any clues in whats going on?

im scared if i start building a sound system the car will just cut out on me. lol. dont want that to happen, especially in peak hour traffic lol.

thanks in advance!

[Fever]

It has to be around the charging system. Check the wires and connections. Gett a DMM on there and check some voltage readings when off, idle, and ~2500rpm. Throw on the a/c and the window defogger for a heavy load and see if the battery light comes on too.

Maybe take it for a second opinion also.

[Curry]

If you are 100% certain that your battery and alternator are working then I would check all connections to make sure they are tight. Is your battery free of corrosion? Break out a DMM and check the voltage across the battery with the car running, lights off. You should be at around 13-14 volts.

[illuzionx]

battery doesnt have corrosion - completely new

the guy that tested it was an NRMA roadside assistance guy and he used the meter to test the alternator and the battery, both working correctly

the battery is plugged in correctly apparently.

ill check all of them other things tonight or tomorow depending on how much time i have.

[Unco]

i defintely wouldn't go putting a sound system until you sort out your electrical problem. it sounds like the alternator is on its way out.

how long does the battery light stay on for?

get yourself a multimeter. wait for the battery light to come on and quickly check the voltage then. if it's less than 14.4V, then your alternator is kaput.

[wiccanferret]

Yeah, test the alternator yourself using this ridiculously simple guide and the cheapest digital voltmeter you can find (Walmart has them for under $10 usually):

http://www3.telus.net/chemelec/Proje...Alternator.htm

I bet your alternator is out. That's all pretty classic symptoms.

[csaxon]

I agree with everything mentioned above ,but also check the alternator belt tension. It may be close to spec but maybe it's slipping randomly. Check the belt condition for slick or worn spots and adjust the tension

[marc780]

doesnt matter what everybody did you still have the problem. Therre's alot of incompetent people out there. Bottom line is your alt should give a minimum reading of 13.9v at idle. 14.0 to 14.9 is better.
I think you could have a slipping belt. With engine off, grab the pulley with your hand and try to twist it. If you can do it without exerting alot of force, belt is loose and slipping, change the belt. If that doesnt do it, change the alternator. An alternator can be marginal, charge intermittently, but still put out barely acceptable voltage when read using a V.O.M., for a long time before it finally dies.

One time i had Pepe Boys put in an alternator. And the battery and alt still kept burning up. It took me a while to determine the problem - the idiots had replaced the alternator with one that had a smaller pulley. And the belt could not be tightened properly and just kept slipping and undercharging the battery. Beware of idiots weilding wrenches.

[95PimpingCamry]

Originally Posted by marc780

Beware of idiots weilding wrenches.

So true!

[wiccanferret]

Originally Posted by marc780

doesnt matter what everybody did you still have the problem. Therre's alot of incompetent people out there. Bottom line is your alt should give a minimum reading of 13.9v at idle. 14.0 to 14.9 is better.
I think you could have a slipping belt. With engine off, grab the pulley with your hand and try to twist it. If you can do it without exerting alot of force, belt is loose and slipping, change the belt. If that doesnt do it, change the alternator. An alternator can be marginal, charge intermittently, but still put out barely acceptable voltage when read using a V.O.M., for a long time before it finally dies.

One time i had Pepe Boys put in an alternator. And the battery and alt still kept burning up. It took me a while to determine the problem - the idiots had replaced the alternator with one that had a smaller pulley. And the belt could not be tightened properly and just kept slipping and undercharging the battery. Beware of idiots weilding wrenches.

If I couldn't get anything conclusive from a voltmeter this is what I would do...

[Unco]

i just wanted to add to this.

in regards to the NRMA roadside assistance...

their job is to get your car up and running in the event of a BREAKDOWN. did he get you up and running? YES. did he do his job? YES.

i don't know how much more people can expect for $80 a year or whatever it costs.

they are certainly NOT a mobile workshop/garage/electrical specialist.

the purpose of having roadside assistance is to get you up and running UNTIL you can get to a workshop/garage/specialist.

some people expect the world for a few dollars... geez.

[mike10872]

I replaced my battery since all the lights, radio etc was shutting off while driving during the day. Autozone checked the battery and deemed it bad. My alternator was still putting out voltage at the time, After driving for about 20 miles, the battery light came on, brake light started to come on also. I checked the voltage from the alternator with a volt meter across the battery lugs while the car was running and it was at 12v only, same as when the car was off. So, even though you had it tested, test it again yourself.