Touareg T1: another battery isssue

Here is the thing:
battery is charged via a cteck charger mxs 5.0.
Charger is at stage 7.
You open the door and battery is showing 14volts.
you turn the key to ACC position and the battery starts draining fast going lower than 10volts !!
I don't have the battery history so it might be just a dead battery but it was fine last august and the car has been sitting in a garage since without the charger. The only issue it had was the htird light was on for 2 weeks for no reason and wouldn't shutdown even if you lock the car. This was then repaired.
So either the repair caused a leak somewhere or the battery is dead.
I will let the battery connected to the charger for a few days and then start hunting for the leak or replace the battery.