Battery is going dead when vehicle is turned off

Certain things are constantly pulling juice all the time. Clock, radio, theft system are always drawing power. Then there could be a light that is not shutting off with its own switch, ie trunk, under hood, etc. Something is pulling juice and you need to start at one end and work your way through to find the cause.

If that fails, an internal malfunction of the alternator would be the next culprit. Replacement time.