If the voltage level is low or the battery is not getting an adequate charge, you may have an alternator problem. Unfortunately, there are no single lights, gauges or other indicators that you can look at to see for certain that it's the alternator. The best way to check the condition of an alternator is to take the vehicle to an auto parts retailer, such as Auto Zone or whatever their competition is in your area. They'll generally test your entire charging system and tell you what's wrong. They do this in hopes that you'll buy the replacment parts from them, so they don't charge for that service. If you don't really want to take it anywhere, see if you can get a volt meter. Test the battery voltage when the vehicle is not running. With the meter turned on, just hold the point of the red wire against the positive battery terminal and the point of the black wire against the negative battery terminal. The battery should show very close to 12 Volts DC. Don't use the AC scale, or the amps or any other feature of the meter, since it is quite possible that doing so would destroy the meter. The battery terminal will not harm YOU. It's only 12 volts, not even enough to feel. If the voltage is low, for example around 10 volts or less, you may need to charge the battery or get a battery boost from another vehicle before the car will even start. Once the car is started, make sure all other charging devices and vehicles are disconnected from the vehicle you're testing. Connect the meter to the battery again and find out what the voltage is when the engine is running. Have a friend bring the engine up just a little from idle when you test the voltage. You should get about 13.5 Volts DC, but your vehicle may be a little different, and the meter may be calibrated a little off as well, but if it's anywhere from 13 to 14 volts, the alternator is probably working ok. Turn on the lights, rear window defroster, AC and wipers to see if the voltage goes down. No matter what accessories you turn on, the alternator should be able to keep the voltage constant. If not, it's probably a faulty alternator.
the battery job is to start the car so the alternator will kick in after the car is running
Alternator going out.
If you can't take off the battery cable while running without the car dieing.
Typically you know your alternator is out when you have to jump start your car numerous times. A way you can test it is by turning on your car and while it's running discount the + terminal. If the car turns off then your alternator is bad. If the car remains in then alternator is good and possible bad battery. Hope this helps
Turn car on remove positive battery terminal if car turns off alternator is bad
If your car doesnt start, it could be the battery. But if the car starts and you unplug the negative cable and the car turns off, its the alternator.
When your battery does not get charge.
The car will be jumping( going up and down) you could only feel it when your car is at a stop.
take it to autozone
The alternator is going bad, may need to be replaced soon
There are a few reasons why your alternator might keep going bad such as rusty latches under the car. You may also have leaks, dents, or parts that need to be replaced on the vehicle that are effecting your alternator.
some times it will sqeal, but most of the time the battery will not stay charged.... take your car to a discount parts dealer that will check your "alternator output" for FREE!!!! most places that sell alt. will check them for free, just drive car there and they will come out and test it while it is in the car. you do not have to remove it from your car!!!!! also you can disconnect battery while car is running ...and if the car turns off or runs poorly after disconnecting battery, then that means the alternator is going bad. but have it check first before buying new one....GOOD LUCK