My stupid battery keeps going flat???

[Mk1Mad J - 16v]

  My stupid sodding battery keeps going flat, put it in on a fresh charge @ 13.5v at night and its down to 10-11v by the morning 

I hadn't used the car for a few weeks as I went on holiday plus don't really need the car, it was down to 2.3v  what the fook? charged it again and its back to 13.5v and holding its charge (when out of the car)

anyone got any ideas, I've disconnected all stereo equipment etc... but that didn't help 

[BobbyT]

check your earths? do you have an alarm? 

[meg1980]

How old is the battery,whats the alternator charging at on tickover.Could be one or the other or like the other man said check earths and battery leads.

[rubjonny]

Battery drain check:
To check for voltage leaks, set your multi meter to measure amps and take off the negative battery terminal. using one lead touch the - battery terminal and with the other lead touch the - terminal wire. Do this with the igniton off and make sure the doors & boot are closed.