my battery light

Sounds like you have a short somewhere. What does the dumby gauge look like on the dash? Is is in the middle voltage wise? have you put a volt meter on the battery to see what it reads before startup and during? i had my battery go on the wifes 02 Explorer the other day. Went to the store and got a new one came home and installed it and the truck still wouldn't start. I thought WTF. I knew it wasn't the alternator because I could jump the truck and it would start. I checked the voltage on the new battery and it was deader than the old one. A volt meter should show at least 13 when the car isn't running. When you are starting the car if it drops to say like 7 or 8 the battery is toast.