I recently brought a R reg Vauxhall Vectra 1800cc it has has always started first time no problem until (approx) 3 weeks ago then one morning i went out to it and i couldn't operate my central locking so i unlocked my drivers door with the key i then noticed the interior light wasn't lit up and when i tried to start the car there wasn't even click at the key the battery was as flat as a pancake so i took the battery off the car and charged up all day then later on i put it back on the car the central locking worked, interior light worked and the car started on the button next day the battery was flat again so i went and brought a brand new car battery put it on the car and yet again it started on the button next day the battery was flat again!! so i jumped started the car and took it to my local garage they told me the battery was fine but the alternator was at fault so i went to my local scrap yard and brought a second hand one for £25.00p i re charged my battery then later on put it back on the car it ran fine for a bout a week i went out to the car today and you guest it! ...the battery was flat again!! any ideas what is causing this problem and how can it be rectified?.

dave, November 2010

I agree with maurice. You need to do a dicharge test.

Huw, November 2010

Best way to see if there is a drain on the battery when the engine is not running iis to disconnect the battery and put a multi meter between the the diconnected battery lead and the battery terminal.

DO NOT TRY TO DRAW ANY HEAVY LOADS with this set up.

Initally you will see a draw from the battery from say the time clock radio remove the fuses from these circuits. By doing this, removing fuses, you should be able to isolate which circuit is draining the battery.

If the battery is not going flat through a current draw then it must be a faulty charging system.

Maurice, November 2010

Hi Dell, Thanks for your advice i have been out to the car in the dark and have had it started while i watched for tell tale signs of any shorts or sparks unfortunately i couldn't see any sparks so its back to the drawing board i'm afraid, but cheers anyway for you ideas mate.

dave, November 2010

I dont think its a bulb on all night that shouldn't flatten a new charged up battery,you have a short some where,in the dark lift the bonnet and get some one to switch on the egnition while you have your eyes studying under the bonnet for small tell tale flashes ,and then get them to start the engine while your eyes are glued to the area under the bonnet.good luck and watch were you put your hands when they start it.

Dell, November 2010

check your charging rate with voltmeter across battery,should be 14v+,you could have another faulty alternator,you could have a duff new battery,check all your conections and earths

cdc, November 2010

Possibly something draining the battery! check to see if the boot light is going out when the lid is shut! if not sure, remove the bulb.

des, November 2010