I was driving home when my car's alternator failed, "alternator failure - not able to charge battery" message suddenly came on. Then the headlights and steering stopped working, and the car died. What could be causing this?
The A3 Sportback e-tron does not have an alternator. It uses the 8.8kWh Lithium battery for alternator purposes to recharge the 12V lead acid accessory battery, which might be declining and now require replacement. If you are towing with the A3 e-tron, you do not receive the expected boost of up to 14V from an alternator, but only 12.6V max. We added a 175W solar panel to the roof of our small folding trailer to get the needed electric boost for our trailer refrigerator.
There was a service recall ("service action 93H4 battery regulation control unit and low-voltage connection seal" for a possible poor connection between the high 8.8kWh battery and the 12V battery. This topic was discussed in some detail at https://www.myaudia3etron.com/threads/12-volt-battery.560/ In short, after some back and forth with the dealer I was able to obtain a new 12V battery for free, although I did fall for the suggestion that I purchase a trickle charger to keep the 12V battery topped up. I use it weekly and have had no more issues with the new 12V. If a 12V battery is drained it is useless and must be replaced, which is expensive at the dealer.
