You can have the alternator tested free of charge at just about any major auto parts store. By the way, a bad alternator will not "discharge" a battery - the alternator's function is to provide the charge to the battery. If the alternator is faulty, then it is not providing the charge necessary to keep other components from discharging the battery.
I had the alternator tested and it was charging. If the alternator has a bad diode, it will discharge the battery. I replaced the alternator and everything is fine.
I pulled the negative cable from the battery with the truck running and the engine quit. Is this a test to see if the alternator needs to be replaced?
Here is a test u can do to see if Ur alternator is good or not . when car is running disconnect the negative battery terminal it's the black wire.If car stalls then the alternator is bad if it doesn't stall then it's Ur battery is bad and u have to replace it
Your 12 volt battery should be about 12.5 volts without the engine running. Test and verify it is. Now with the engine running test again, Voltage should now be around 13 to 14 volts. If not, then your battery or alternator are bad. To check a battery try charging it with a battery charger.
There is no problem...the problem was the alternator. You have fixed the problem.
The gauge inside is telling you how many volts your alternator is putting out, not yoru battery. Go have your alternator tested to see if it is putting out 14 volts or more...........if not, you are drawing more current out of the battery then what the alternator is replacing and you are going to end up with another dead battery. They can test alternators at Autozone for free or you can go get a multi meter and test it yourself. Have the alternator checked.
to see how strong your battery is
The battery light is letting you know that the alternator is not charging the battery. Check to see if alternator is any good. Also check to see if belt is hooked up.
First, get a volt meter. Test the voltage of the battery before starting the car, then start it and see if the voltage increased. You should see a jump of about 3-4 volts. Alternatively, if the car has a manual transmission, you could tow the car in gear (very slowly, about ten MPH in first) with the engine off and the battery removed and test to see if the alternator is generating power. Without the battery it should only make about one or two volts, but you will be able to notice it on a voltmeter.
Why do you want to unhook your battery??? If the alternator is good the car will continue to run, if it dies then you have a bad alternator this is why you would want to unhook the battery cable to check and see if you have a bad alternator
Assuming the new battery is good! The usual problem why a battery is not charging is the alternator. The battery will be discharged if the alternator is not working properly when you start the engine and when the engine is running, etc. The vehicle uses the batteries electricity instead of the alternators electrical output, and of course if the battery is not being replenished by the alternator the battery will fail in a short period of time. You should test the alternator to see if it is putting out between 12 and 15 volts. Another possible things that could be the problem with a New battery failing so quick is, maybe the proper amount of acid was not put into the battery, a short in the wiring, etc.
Recheck your battery to see if hooked up right.
Either check your alternator or your battery life and replace as see fit.