Parasitic drain

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Robbo135
Newbie
Posts: 8
Joined: Wed Jun 06, 2018 3:27 am

Parasitic drain

Post by Robbo135 »

Hi Guys,
I have a bmw 323 E90 and customer complaining of a repeated flat battery, have checked battery, charge rate and carried out a parasitic drain test. I'm showing a current draw of 250mA when vehicle has finally gone to sleep (this has taken approximately 30 mins). My question is what is an acceptable drain? Any help appreciated.
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liviu2004
TwoWaves
TwoWaves
Posts: 474
Joined: Sat Mar 19, 2016 8:23 am
Location: Netherlands

Re: Parasitic drain

Post by liviu2004 »

250 mA is too much. There are several methods to determine the faulty circuit, you can try fuses voltage drop test and why not, thermal imaging camera.
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victor2k
TwoWaves
TwoWaves
Posts: 337
Joined: Thu Jan 28, 2016 7:17 am

Re: Parasitic drain

Post by victor2k »

Hello,
Some faults in engine control module(like smart sensor,alternator,aux water pump-all share the same bus of data)?
I think a current consistently over 50 mA must be investigated.
Best regards
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Robbo135
Newbie
Posts: 8
Joined: Wed Jun 06, 2018 3:27 am

Re: Parasitic drain

Post by Robbo135 »

Thanks Guys. Unfortunately I don`t have a thermol imaging camera but that is a flash suggestion. I -believe that I am down to the fuse pulling or volt drop testing methods for the time being! I will be testing with the 50mA and less in mind.
Thanks again
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Zap
Newbie
Posts: 1
Joined: Sat Jul 07, 2018 1:18 pm

Re: Parasitic drain

Post by Zap »

So, I don't know about BMW's specifically, but I know that Fords made in the same time period needed to be at rest for at least 40 minutes before going to sleep. I also remember reading TSBs from other german automakers (maybe Audi?) that say to let the vehicle sit for at least 2 hours before doing a drain test.

What's the drain after 2 hours?
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