"Battery" light is on.

[Gavin Allan]

My "battery" light started coming on today. I find that it comes on whenever the engine RPM is below 3000. The voltmeter stays in the "normal" range. The headlights get dim at idle, but brighten up when the engine is speeded up. I checked connections at the alternator and the battery, and the belt is nice and tight. Think I have a bad alternator?



'03 Adrenaline, 43,000 miles.



Thanks for any advice.

 

[Dallas Starr]

I don't know how it is there but you can take your trac into a shop (here Canadian Tire) and some will test your alterator and battery for free.

 

[Todd Z]

If the battery connections, wires on the ALT and the belt are good, Sounds like the Alt is shot.....

Todd Z

 

[Tom Schindler]

Gavin,



Autozone can check your charging system for you.





Tom

 

[Chops]

A quick test:

A car battery is comprised of 6 cells at 2.1v each, hence 12.6v for a charged battery.

A battery won't charge unless the charging voltage > than batt voltage, most charging systems are regulated at 13.8v.



With lights on at idle, you should have ~13.8v at the battery, If not, your alt. is defective.

 

[Gavin Allan]

A $133 rebuilt alternator from AutoZone fixed me up. I measured 14.2 volts idling with the lights and the air condition on.



Thanks for the advice. Hope this one lasts longer.