1993, 900 low battery stops car

[WWPerk]

My 93-900 occasionally (3X in the past year) has lost power and eventually stopped working. Twice, the car was towed to a local independent Saab mechanic that charged the battery and it worked fine for weeks. Recently, my daughter took it to college and let it set for a few days. She started and ran it and again it lost power (10 MPH max.) before it eventually died. Do I need a new battery eventhough the one in it holds a charge? The alternator has been checked out and seems to be good.

Any Thoughts?

[herkyhawki]

There is a timer relay that runs the electric fan for 10 minutes after the car is shut off. This relay is known to stick and run the fan until the battery dies. Check this relay!