Random Flat battery???

Over the last week I've had 2 instances of a flat battery neither of which make 'sense'

first was I'd been out in the car a few times in the morning, came to it in the affy and it was dead to the point of needing a jump start.

second was one morning, it had 'just' enough to spin the motor up (The clock reset itself so the engine must have sucked every last volt

Yet other days its fine, spins up quickly, no issues etc.


I've checked the battery - 13V when off, 15V when engine running, check silly things like boot interior lights going off(yes, I got the wife to shut me in! ), made sure all lights off by walking round teh car when its dark,

Anyone any idea whats left 'enabled' when the ignition is off? I seem to recall people saying the ciggy lighter is but I've nothing plugged in there.


The only weird bit I've seen is the battery with one of those 'coloured' indicators, it says green = good, grey = charge, white = replace. Mines Black.......

Any Ideas?