Battery losing charge

[N8Gow]

Hi Guys,,

I hope you can be of some help as I may have pulled out all of my hair by tomorrow......

I've just bought a 525i on a 05 plate; the battery is losing it's charge overnight.

Being technically minded & quickly got the fluke out & checked it was charging, A ok.

As the battery was 5 years old I purchased a new one to eliminate that out of the equation.

Still, lost it's charge.... So then I disconnected & connected my age old friend, test lamp.

Ripped all the fuses out & began to replace one by one... Turned ot to be more of a chore than a challanger tank.....

Too many fuses brought up the draw of current than I expected....

So I just put the fluke over the terminals in parallel & observed the voltage drop over a set period (15mins)

Outcome: the car dropped 50mA over a 15min period car open, then 100mA when locked,,

I took out the alarm fuse (51) thinking it was the alarm that was at fault.... re-evaluated & same result...

Conclusion: HELP!!!!!!!

[N8Gow]

Sorry 50mV drop and 100mV respectively......

[andy-mcq]

hmmmm so it shouldnt be the alternator then

i take it nothing is getting left on? lights, all doors, boot locked, radio off etc etc.

not 100% but are all earths correct?

welcome to the club to

[N8Gow]

Thanks Andy..

Yeah,,, all the obvious bases have been covered.... I spoke to a chap at a dealer & he could only agree with my methods,,Apart from the obvious of bringing it in. But I have always raised to the challenge....

Can anyone suggest if buying a diagnostics plug in would be beneficial, or, can recommend a reliable one.

I've had historical success with rangerover off the shelf diagnostics.

[G4VHD]

As an auto electrician myself, from what you have said, you seem to know your poo,

Im at a loss, take it to the garage mate, it looks like you have covered all obvious bases,,,

Welcome along too