RSQ3 Battery/Charging System Warning Signs Revealed

Had similar issues with my 2019 RS4. The symptoms pointed to a deteriorating battery health, slow cranking, dim lights, and inconsistent electrical systems. The voltage drop during starting was the key indicator. After testing, it showed the battery could not maintain proper voltage under load. The alternator and voltage regulator tested fine, but the battery itself had multiple dead cells. The original battery typically lasts 4-5 years under normal conditions. At 89k km, this is a common failure point. The low voltage symptoms get worse in cold weather and after short trips that dont fully recharge the system. Got it properly diagnosed with a battery load test. Required a complete battery replacement, including reprogramming the battery management system. Not a complicated fix, but definitely needed professional service due to the coding requirements on modern Audis. The power supply issues can damage other electrical components if left unchecked, so addressing battery problems early is important. After replacement, all electrical gremlins disappeared and starting performance returned to normal. Worth getting a proper diagnosis with the right diagnostic equipment rather than general checks. These symptoms typically dont fix themselves and usually indicate end-of-life battery condition.

Thanks for sharing your RS4 experience, matches exactly what I went through with my RSQ3. My electrical problems cleared up completely after fixing the battery too. Did you remember roughly what you paid for the full battery replacement including programming? My charging system is working fine now but curious how costs compare. Also wondering if you had any other electrical issues pop up since the battery swap?

After getting professional service, my alternator issue and low voltage problems were fully resolved. The complete repair came to 290 Euro, which covered replacing the heavily discharged battery and necessary programming. This was about 6 months ago, and the electrical system has been running perfectly since then. The battery terminal connections were also cleaned during service, which helped ensure optimal power delivery. Zero electrical gremlins have returned, no more dim lights, starting issues, or voltage regulator warnings. The investment in proper diagnosis and repair was definitely worth it to prevent potential damage to other electrical components. Just make sure to drive regularly enough to maintain proper battery charge. Short trips can sometimes prevent full charging cycles, which isn't ideal for long-term battery health.

Thanks everyone, wanted to close the loop on my RSQ3 situation. Took it to a different workshop that specializes in German cars. They properly diagnosed a failing battery that was causing the charging system problems. Total bill came to 320 Euro including the new battery, programming, and a full electrical system check. The battery terminal connections needed serious cleaning too, there was quite a bit of corrosion built up. The alternator and voltage regulator tested fine, so thankfully it was just the battery. Been about 2 weeks now and all the electrical gremlins are gone. No more dim lights or hard starts. Car feels like new again. Definitely learned my lesson about getting proper diagnosis from specialists rather than general mechanics. The right tools and expertise made all the difference in fixing it right the first time.