Quote:
Originally Posted by Somerandomguy
After checking all of the fuses for current, i found nothing so am wondering if I have a problem with the BEM or alternator. Ive been monitoring voltage whilst I drive, and it seems a bit low, ranging from 12.7v up to 13.6v depneding what's switched on.
So im thinking that rather than a drain, the battery isnt charging - do any of you know what your normal voltage is?
Cheers
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Some thoughts:
1) Have you checked ALL the fuses? They're all over the car; 8 places by my count
2) What is the version of the BEM in your car. Some of them have a flash update to correct issues. Sadly, Audi never said what the faults were, only that BEM firmware above 240 and below 510 should be flashed to 0510.
3) The alternator is 'clever' in the A8 in that the voltage output is selectable - by the BEM. THE BEM selects the appropriate voltage and sends that value to the alternator. Thus there is no 'normal voltage'; it changes in each car as the conditions dictate. In drastic conditions, the BEM will also speed up the engine idle if it thinks the alternator is not up to keeping the charge up at normal idle.
If you have VCDS, you can monitor alternator output in real time using BEM Measuring blocks.
4) A fully charged battery is 12.6V, so any output voltage from the alternater over 12.6 will be charging the battery.
Julian