Car battery/electrics

[Calvados]

I bought a new battery in September for a Clio 1.9 deisel.
I haven't used the car since the end of October because the tax ran out, so I have left it on my driveway. The battery is totally flat now. I have run the engine a few times but now I have to jump start it. I took the battery back to see if it was faulty and they said it had been overcharged and it was totally dead. I don't understand this. How can it be overcharged if the car hasn't been on the road? Could there be a fault with the alternator or the electrics? Thanks.

[BillyNoMates]

It is possible that the regulator in your alternator has failed. This 'could' cause overcharging when the engine has been run.

How long was the engine run for ?

[woodchopper]

As Billy said - could be a fault with the alternator - If I remember correctly one way to check if the battery is being overcharged was to connect a voltmeter to the battery you should get a reading of about 12v , start the car and the voltmeter should rise up to about 13.8v - any higher will damage the battery.
It is possible to buy a duff battery.

[Gef]

Have you filled in a SORN? If not there will be an �80 fine heading your way.

[Calvados]

The company have changed the battery and it seems ok now.

The car isn't registered to me, although it is stood on my drive-way.

Thanks for your help guys!