last night when i started my kitty the battery light stayed on. i drove about .5 a mile stopped switched off the car. when i started it the light didn't show drove about 20miles no light no problems. should assume the computer was drunk?

 

MosDef, I would say to put a multimeter on the car and see what the voltage is. It could have been something as simple as a drop of water inside of a connector causing the alternator to not respond properly. But then, it could be a lot of other things.

In short, put the multimeter across the battery, should read 12.6 VDC. Anything less and your battery is not at full charge (more investigating is needed). Now, start the car. You should see the multimeter jump up to around 14.4 VDC for a few seconds and then slowly come down to around 13.7 VDC (13.3-14.0). If you are down under 13.3 VDC, do a quick check of the alternator by kicking on your dash blower to max speed and turning on your rear defroster. Does the voltage stay at the same value or did it drop. If it stays at the same value, then that is where the computer is controlling the voltage. If it drops (especially to below 12.6 VDC), then you have a problem with the alternator.