94 SL2 - dead battery - followed by rough running engine

Hi all - interesting problem. My daughter's 94 SL2 has an issue - the car wouldn't start, and after finding a dead battery (a year old battery!),
jumping it so get the car started, the engine runs fine for a time (a few minutes). While it is running the battery light is on, and then when the battery light goes out (after partially charging I'm assuming), the car begins to run very roughly, almost as if it is missing. Turning the car off yields another dead battery!
Any ideas??
Thanks - Eric
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Sounds like your alternator is bad but the battery is in good shape. A good battery, after run down, will recover if you let it sit there. It may not recover enough to start the car(though in my case it did) but it will recover enough to run the car for awhile. So whats happening is when you get a jump, the battery is running the car for a few minutes. Once the battery starts running down lower and lower the car starts to run rough since there isn't enough juice to keep the plugs lit. When you let it sit for awhile then try it again it works again since the battery recovered some. Check the batt. with a voltmeter when the engine is running. I'm guessing you will only see 12 volts. If you do get 12 volts it means the alternator is bad like I'm betting on.
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Let me get this straight; You've had the car for 9 years (since 1994) and this is the first time your alternator has failed? And it failed in your drive way? Dang you're lucky. I've lost 2 so far on my 94 SL-1, both of them just a wisp out of the 3 year/36,000 mile warranty; the first about 90 miles from home so between the tow truck, a night in a motel, and the alternator it was almost $500. The second failed in town. The current one only had a 1 year warranty but it's now just over 3 years old and I'm seriously thinking about replacing it before my next long road trip cause I KNOW, I JUST KNOW it's going to fail soon and at the worst possible time in the worst possible place. ron herfurth
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Turned out to be the alternator as suggested by several posters. One tow and a new alternator, and now all is well in Saturn land. Thanks for the help!
Eric

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