why is my battery draining overnight. i have got a silver top bosch battery and a uprated alternator which seem to be ok.when i go to start it in the morning the battery is flat to start the car,when you put the jump leads on it starts straight away and you can dive away no problem.is it a good idea to take the earth leads off the batterey overnight and then see what happens in the morning to give you some idea of what wires draining it.
any would be much appreciated
cheers

 

If you take the earth wire off the battery and use a multi meter to check for drain between the earth battery post and the earth wire.

 

When the car is started does it run ok and not cut out.

 

tou only have to put the jump leads on and it starts straight away and runs perfect

 

I would do the checks as Glenny Boy suggests.

Just quickly though, how old is the Bosch battery? Only reason I ask is that I used to swear by the Bosch Silver batteries on all my cars . They were brilliant. Then, suddenly they all started dying within a few weeks of each other (5 cars with them on @ the time). Did not matter whether they were used daily or left parked for a week. Almost identical problem as yours.

 

i took my earth leads of the battery overnight put them back on this morning and the car started straight away,so what would you check next
cheers

 

Do as above to confirm battery drain, then disconnect all your ancillaries (Stereo, Amps, Alarm, etc..) one at a time and repeat the above test until you find the culprit! Alternatively remove your fuses one at a time and repeat above test again until you find which circuit is draining.

 

there is a fuse testers on ebay for 18 pound it says pull out the spaded fuse and push the tester on and it says it will find the fault easy,anygood

 

where is the switch or whatever that turns the boot light off when you close it
cheers

 

just take the bulb out to check!

ideally u need to do a current drain test with a multimeter.

 

i have the exact same problem. sooo annoying. i might try and take earth off and see if it starts. then start taking wires off the possitive one by one overnight.


arrrgggggggrrrrgggg

 

well something has got to be draining my battery coz my central locking wouldnt even work lol.

it aint alternator.

i put new battery in last month and has been absaloutly fine coz i been using it 2/4 times a day everyday.

then christmas day and boxing day i didnt use it and it kind of struggled to start but was ok in end.

then yesterday. whole of sunday so 24hours i didnt use car.

i go and start it this morning and nutin there.

i come back from work and central locking wont work lol

so now i got to look for WHAT IS DRAINING IT

 

well i might just try solve problem by taking to an auto electrician and get it on the diognistic or something like that

 

As a couple of people said you need to disconnect the battery earth and connect a multimeter inbetween in ammeter mode and see what sort of current you have flowing.

Chances are its something that has been wired into the car that is causing the drain, like a stereo system or gauges for example.

 

have you done any work on it recently? check that over.

happened to me after i fitted an alternator, central locking wouldnt even work, i nipped an earth at the positive terminal on the starter.

other than that, if you have the time, charge the battery, then take a few fuses out a night till the draining stops and find which one it is that way

 

cheers mate
what fuses would you start with or is it just pot luck

 

find out if theres any common faults that could be doing it.

parts breaking down etc.

if not id start with aftermarket parts, cd player circuit etc.

on the first night id disconnect the main positive lead too as the starter and alternator are not fused, so you could have tried all the fuses when its the alternator/starter draining it.

 

cheers ,i will start tomorrow and post what i find out