[thuss]

Hi

I was wondering if somebody could help me?(I also hope I'm in the right section)

I keep getting increased battery discharge and the car wont start in the morning.

Can anyone advise me on how to do a parasitic test for a 2009 e90 325d ,or advise me where I am going wrong?

this is what I've attempted to do
I took the negative cable of the battery and waited 30/40minutes, put my multimeter into amps mode and placed the probs between -ve battery terminal and negative cable and suddenly the rear boot light came on and I get a reading of 7.4 amps?

(Just thinking about it should I have disconnected the blue connector of the red terminal connection above the battery?)

I removed and charged the battery overnight. I stopped when it read 12.7v and then reinstalled it and started the car and I am getting 15v across the terminals and the screen still shows increased battery discharge.
Either I got a duff battery or can I have faulty intelligent battery sensor? because I dont belive a fully charged battery would within two seconds of starting the car show a fault.

I hope someone can advise? Thanks in advance

[Aragorn30d]

your test was correct, but you need to wait 15-20mins for the cars systems to goto sleep, until that happens you wont really know what current draw is being applied.

Ie you need to connect up your meter, close the car and leave it like that for a while.

I'm also not sure you charged the battery correctly. Typically you apply a voltage of around 14v then wait for the current to drop down very low which indicates the battery is full.

[thuss]

Thanks for the reply.

(I did lock the doors and opened up the boot waited and put the meter in place and the alarm went off)

But if I hook up the meter whilst it is shutting down (fluke 10amp fuse) wont there be a chance that I will blow the meter(meter fuse)?

The other thing is do I have to remove the large blue connection from the top red strap like connection block?

I was using a halfords automatic car battery charger- whilst connected I was reading with mm a voltage of 13.56 which after a few hours became a I think a pulsing charge.

thanks in advance

[Aragorn30d]

yeh if you lock it then disconnect the batteyr the alarm wont like that much.

Leave the car unlocked, put your meter in place (somewhere you can see it!), and then shut the boot and let it sit for a while. Dont need to lock it.

You want to be able to view the readings without opening doors or boot etc as this will wake the cars electrics up again.

[thuss]

thanks did the trick