Q3 Electrical Gremlins: Battery Not the Culprit

Had similar charging system problems with my 2011 Audi Q5 2.0 TFSI. Started with slow cranking and dim lights, exactly like your symptoms. A voltage drop test revealed multiple issues rather than just a weak battery. The main problems were: Corroded battery terminals causing poor connections, Failing alternator not maintaining proper charge, Damaged wiring between alternator and battery The battery replacement alone did not resolve it because the alternator was not charging properly. The voltage regulator inside the alternator was failing, causing inconsistent charging output. After replacing both alternator and battery plus cleaning all connections, the low voltage issues disappeared completely. This was a serious repair since the failing charging system could have left me stranded. The alternator issue was gradually getting worse, drawing excessive power from the battery until it could no longer hold charge. For proper diagnosis, the entire charging system needs testing, not just battery health. Look for shops with specialized electrical diagnostic equipment that can perform comprehensive voltage drop testing across the charging circuit. These symptoms rarely fix themselves and typically worsen over time, affecting more electrical systems until addressed properly.

Thanks for sharing your Q5 experience. It matches what I am seeing in my Q3. Just had my alternator replaced last week since the battery voltage kept dropping even with a new battery. The voltage regulator was definitely shot. Before I take it back for a follow up, did the repair fully solve all your electrical gremlins? Would be great to know how much you ended up paying for the full fix. Always good to have a price reference when dealing with these charging system repairs.

Following up on my Q5 experience, yes, replacing the alternator completely resolved all power supply issues. After the repair, the battery voltage stayed stable and all those annoying electrical problems disappeared. My total repair came to 290 Euro, which covered fixing the heavily discharged battery system. The mechanic found that once the faulty alternator was replaced, the charging system worked perfectly. Regular voltage tests now show normal readings, and the battery terminals maintain proper connection. The undervoltage warnings I kept getting are now completely gone. No more dim lights, slow cranking, or system malfunctions. The investment was worth it since these charging system problems can cascade into bigger issues if left unfixed. If your symptoms match what I experienced, having the alternator replaced was definitely the right call. You should see a clear improvement in how your Q3 performs, especially during cold starts.

I finally got it properly fixed. Went to a well-equipped shop that specializes in electrical diagnostics. They confirmed the alternator replacement fixed the main charging system problem, but also found a few other issues. Total bill came to 420 Euro including: New alternator installation, Battery terminal cleaning and replacement, Ground wire repair, Full system diagnostic test The power supply is now working perfectly. All electrical systems function normally, no more dim lights or slow cranking. The battery holds a proper charge and voltage readings are steady. Cold starts are strong again. Glad I got it done properly instead of continuing to guess at the problem. The comprehensive testing approach saved money in the long run by fixing everything at once rather than replacing parts one at a time.