Battery won't hold charge

I have a 92 Bonneville. Something continues to drain the battery. Alternator has been checked out twice and is fine. I have installed 2 new batteries so far. Charge will last for a while then I may go to start it and it is dead. I can drive it for a while turn off and go back out to start it in an hour or less and it won't start. Any ideas??????????????????????????:banghead:

You can measure the drain with a voltmeter set to measure up to 10 amps. Just remove the negative cable & connect the meter between the battery & cable. Make sure everything is off while performing this measurement. The measurement will spike & then drop down. The drop down reading should be less than 1/10 amp. If the reading is high then you need to pull one fuse at a time to narrow down the problem. Let us know what you find.