Quote:
Originally Posted by Somerandomguy
I thought I had checked them all, but probably not, as i had only checked 4 locations- left and right front dash, pkus left and right boot alcoves. Where are the rest?
BEm is H12 0550, which looks like the latest version. I realise that it is a smart system, but sometimes after a long drive im sure I have even seen the voltage drops below 12.6v, so Im trying to establish whats "normal" behaviour.
I had a look at the measuring block today after charging overnight followed by 25 miles driving and at idle, the BEM is reporting positive current flow between 2A to 10A, dropping to -14A with the engine off. Interestingly the requested voltage was over 14v, but the battery voltage was 13.7v.
Ive spoken to an audi mastertech friend and hes offered to monitor it over a few days with a scope to see if he can see anything
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1) As well as the obvious locations at left/right dash ends and left/right boot there are apparently 4 other locations: Plenum chamber, behind left dash panel, right A pillar, front right footwell. [See PDF - A8 Current Flow diagrams - Section 802]
2) That's a good level of the BEM - latest [and last] version, as you suggest
3) Battery voltage with engine running is actually alternator output voltage. You can only measure true battery voltage via VCDS with ignition on / engine off and no charger. Were those voltages with engine off?
4) I've come to conclusion you can only really measure battery drains with fancy £1000+ kit that dealers have. You need real time measurements with an inductive connector on the battery lead with all the car's systems shut down. Sadly I don't have access to one of those.
Julian