Parasitic Battery Drain Measured on 1990 Audi 100

[Grant Lenahan]

Just FYI, on newer audis, the drain is also quite large for about 15 minutes, and then it goes into sleep mode band the current falls to~ 3ma.

I was certain i had a problem until i became *really* patient. (ref: 2002 S6)

Grant

On Jul 21, 2015, at 12:15 AM, mboucher70 hotmail.com <mboucher70 at hotmail.com> wrote:

> 
> I've always noticed that my Audi's car battery ran down faster than other cars when the car hadn't been driven for a while.  Two weeks ago I did 1000km of highway driving then parked it and didn't drive it for 14 days.  Yesterday after 14 days, I measured the voltage and it was down to about 11.5 volts.  
> 
> 
> I decided to finally measure what the drain on the battery was, when the car is just sitting parked.  And further, to see what was actually responsible for that drain.  I did this by routing the battery through an ammeter. 
> Results:  Total drain: just over 1/4 of an amp. 261 mA to be precise.
> 
> 1.) Surprisingly, almost all the drain is running across the 30Amp fuse that powers the "Passenger Seat adjuster, control unit seat memory".  That was using 210 mA.
> 2.) Second was the central locking and anti-theft fuse, which accounted for 31 mA.
> 3.) Third was the fuse that controls the radio, trip computer, and climate control, among other things.  This accounted for 19mA.
> 4.) With those three fuses pulled, the remaining drain was 0.4 mA.  None of the other fuses accounted for this small insignificant drain.  
> 
> 
> So the only real surprise for me was the seat memory using that much current.   Anyone else ever notice this?  Could that have been simply the design of those early electronics, or has something gone wrong.  The seat memory seems to work great, although I never use it.
> 
> 
> I would've expected the memory on the CIS-E III to consume a bit, given I was reading on the mA scale.  However when the fuses for "engine" were pulled, nothing changed.
> 
> Not that it matters, but I'm still curious what that final 0.4 mA that didn't pass through any fuses might be.  I'm guessing the voltage regulator on the alternator?
> 
> Thanks for any thoughts,
> 
> MC
> Audi 100 1990 I5 Non-Turbo Non-Quattro NF Engine
> _______________________________________________
> quattro mailing list
> http://www.audifans.com/mailman/listinfo/quattro
> http://www.audifans.com/kb/List_information