93 chevy lumina. My dash battery light comes on for the first 5 minutes of driving. The battery voltage gauge on the dash shows about 10 volts as well. Everything then goes back to normal until I shut car off. When I restart the car same thing happens again. I replaced alternator 3x different brands, put new battery and replaced bad starter. Also, my alarm system chirps randomly when car is off. It only does it intermitantly. I think it does it when the battery is low on charge. Could it be the ECM?

I would test to see if there is a short in one of your circuits that is draining the battery overnight.

Disconnect the negative cable from the battery.

Place a test light between the the cable and the battery terminal.

Insure all doors are closed and any thing else that would illuminate a light or cause an open circuit.

If the test light is illuminated you have a short in a circuit.

To find the circuit responsible, remove a fuse, close the door and see if test light is still iluminated.

There are those occasions when more than one circuit could be the culprit.

On a Grand Marquis I had to remove ever fuse then start replacing them one at a time, with only one in the fuse block at a time.

Hope this helps