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Take it to Autozone or whatever you have locally, They will put a tester on it for free and will tell you if the alternator output is what is should be and whether the batter is still good/partly good etc.
If Its the alternator, a jump won't help you because the battery is run so down it won't be able to start the car except after charged up for a long time.
Battery light is usually, but not always, on if it is the alternator.
Got a multimeter? If so, you don't need a load tester...
*edit: Looked at your nunbers. Alternator at maximum output when its running, looks good.
I agree with having it tested.. But another test that you can do is to disconnect the negative terminal from the battery.. Let it sit disconnected overnight (or whatever time it would normally need to be jumped after) and then reconnect the battery.
If it doesn't crank fine.. Battery is toast. if it does.. You could have something pulling it down.
If it's the alternator you wouldn't be able to drive it at all, because the alternator, not the battery, actually runs the car once it's started.
Found this out the hard way with a friend's Dodge Ram van about 20 years ago as we were caravaning back from a gig and got stranded out in the middle of nowhere. Jump start didn't work. Sending one of the other guys who were driving with us to buy a new battery didn't work. I had to trade batteries with him (I was driving a 1993 Voyageur), so he managed to get home with my good battery, while my working alternator charged up his dead one. When we got to his place we traded back.
If it's the alternator you wouldn't be able to drive it at all, because the alternator, not the battery, actually runs the car once it's started.
Found this out the hard way with a friend's Dodge Ram van about 20 years ago as we were caravaning back from a gig and got stranded out in the middle of nowhere. Jump start didn't work. Sending one of the other guys who were driving with us to buy a new battery didn't work. I had to trade batteries with him (I was driving a 1993 Voyageur), so he managed to get home with my good battery, while my working alternator charged up his dead one. When we got to his place we traded back.
Yes that's true for the OP, but its only required if you have fuel injection. I learned that one too.
I had a china made lighter socket power cable for my gps break while using it once. The plug that goes in to the gps came off (the mini usb head), and I heard a pop through the stereo. It took about an hour for my battery to go from perfect to completely dead. So dead that the fuel injection was sputtering and couldn't keep up, and using the window switch was near killing it, it eventually lost all the juice and couldn't run the fuel injection then died. I replaced the alternator at a rest stop, got a (5 minute) jump, and was good to go.
Take it to Autozone or whatever you have locally, They will put a tester on it for free and will tell you if the alternator output is what is should be and whether the batter is still good/partly good etc.
Do they test the battery under heavy current draws?
If Its the alternator, a jump won't help you because the battery is run so down it won't be able to start the car except after charged up for a long time.
Battery light is usually, but not always, on if it is the alternator.
Got a multimeter? If so, you don't need a load tester...
*edit: Looked at your nunbers. Alternator at maximum output when its running, looks good.
Sounds like a weak battery to me.
If it's the alternator it won't run. You can run a car without a battery.
If it's the alternator it won't run. You can run a car without a battery.
A car can certainly run without an alternator if there is a good battery connected. The battery will supply the juice but once it's depleted the engine will stall.
This is actually a very common scenario where the alternator is going bad and is no longer charging the battery or only intermittently. The battery is capable of running the engine on short trips but usually gets depleted to the point it can't start the car next time. You get a jump and it gets charged momentarily and may last until the next start. Rinse and repeat.
This isn't healthy on a battery and a deeply discharged battery or one that can't hold a charge isn't healthy on the alternator either. An alternator is only meant to charge the battery with whatever was used when starting the car. A bad battery is a huge load on the alternator and can burn it out if the battery isn't replaced soon. Likewise a battery deeply discharged may not spring back and sufficiently hold a charge when charged again.
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