Get the car started and take a reading on a Volt Meter across the battery, As you slowly rev up it should go up to a Max of 14.5 Volts and no more.
If it goes over the Voltage Regulator is faulty (Part of the Alternator) and may have cooked the battery.
If it does not get above 12 Volts it could just be a loose Belt or the Alternator.
If it gets up to the 14.5 Volts switch Off and check V/M reading should be 12 Volts. If not replace it.
Leave for 20 minutes then check V/M reading again. If still 12 Volts battery is OK.
Batteries are 6 X 2 Volt cells but will only give 6 X the lowest cell so if one is only 1.5 Volts it will only give you 6 X 1.5 Volts = 9 Volts.
Andy C
That's the warning light that tells you the battery is not being charged. The alternator is junk, however a battery with a dead cell can fry the alternator so if the battery is over 4 years old replace them both.
It could be any of those. How fast does the battery charge? If it charges quickly (say in 30 minutes) then the battery is bad.
Places like AutoZone and Advance Auto Parts will test batteries and charging systems for free.
Get a hold of a volt meter, some shops check your battery voltage for free.
Check it when the car is running
If your getting somewhere between 13.8-14.5 volts then you can cross the alternator out. When checking the volts, turn on the wipers, lights, and anything that'll drain the battery...if it drops below 13.8 then the alternator is shot.
If it's not the alternator then it's the battery.
bring the battery to canadian tire and have them test for the battery for free if good its the alternator.
The battery light in my car is on and im not sure what it is, maybe an altinator? Bad battery? So i charged it up and it will start and run fine. Then when i shut it off it wont start up like the battery is dead, maybe the altinator is trying to charge a bad battery? Or the battery is good and the altinator is sending too many volts to the battery, any ideas on what could be the issue, throw me any possibility.
Thanks btw its on an 03 eclipse gts
