You lot are bad luck...

[RalphG]

I wouldn't describe myself as an oracle (unless its the one from Delphi). But at least you didn't describe me as 'the SQL Server' - I would have taken offence at that!

[D3monstrate]

UPDATE:

Got my car back, they said it was the battery, so theyve changed it and all seems well *touches wood*.

[purple_daVe]

hey,
recently had similar out of blue, first thing i did was have battery checked and confirmed it was dud so parted with some notes, worked a charm for about 4 days then problem returned, had alternator checked fine apparently, poor thing couldnt even cope with being stood in works car park for length of a shift so i was charging 2 batteries evey day one to get me to work one to get me back. Turns out alternator was open circuit so all the electrickery was flowing backwards turning the alternator into a nice little engine bay heater when stood, which is why alternator test showed fine as technically it was charging when running.
obviously hope this isnt your problem and your good to go

[KevG]

First of all get a volt meter on the battery when the car is running, this should show that amount of volts the alternator is giving out should be 14.2volts.

Car Not running

Discharged State:

12.5v

Charged State:

12.7v

Car running (Charging)

Charging

14.2v

Loaded Battery (lights, Rear demister, heater, etc)

12.7volts

Lead acid car batteries are not very good in the cold, the acid tends to get very weak and can freeze giving a poor cell, this causes the cell to die over a short period of time.

Sounds to me that you have a weak battery, it happened to myself last week, managed to catch the car and run, but all the warning lights stayed on!!!!, got a jump from the wifes car and it went no probs.

[D3monstrate]

AHHHHHHHHH!

Went to drive to work today and guess what... completely dead battery!

Once again I had to get one of my neighbours to fill my car with electricity, and I went straight back to the garage and kicked up a bit of crap. The battery light didnt come on when I drove home, and I also managed to start it and drive about for a bit after, so it was over night the charge went missing...

They said they would work on it tomorrow

[RalphG]

One of the reasons that I had ECU on my list is that a fault in the ECU can cause the main relay to be left closed after the car is locked. This will lead to the battery draining overnight.