VW Arteon Battery Issues: Voltage Problems Decoded

As someone with some experience working on VWs, I encountered a very similar electrical problem with my 2019 VW Passat. The symptoms you describe match exactly what I experienced, struggling starts and low battery voltage readings. After monitoring the battery terminal voltage, my workshop diagnosed a failing battery that wasnt holding proper charge. The alternator was tested and proved fine, but the battery had degraded significantly. These symptoms often point to either a battery issue or alternator problem. The fix involved: Complete battery diagnostic testing, Replacement of the main battery, System voltage check after installation, Computer reset to clear error codes Total cost was 290€ including parts and labor. Since the replacement, all electrical problems disappeared and starting has been reliable. To better assist with your specific case, could you share: How old is the current battery? Does the problem occur more after short drives? Have you had any recent electrical upgrades installed? What voltage readings are you seeing at the battery terminal? The battery systems in the Arteon and Passat are quite similar, so knowing these details would help determine if you are facing the same root cause.

Thanks for the detailed reply. After my latest service at 25032km, the workshop did a voltage drop test which showed normal alternator output but concerning battery health readings. The battery terminal voltage drops to 11.8V during startup, which matches your description. I havent made any electrical modifications. The issues happen mostly after the car sits unused for 2-3 days. My voltage readings at idle are lower than factory spec, around 13.2V, pointing to potential charging system problems. Given the similarity to your case, I will schedule a comprehensive battery diagnostic to determine if replacement is needed.

Thanks for those additional details. The voltage readings you shared strongly indicate deteriorating battery health, very similar to what I encountered on my Passat. That 11.8V during cranking is definitely below the acceptable threshold. The fact that problems worsen after 2-3 days of sitting matches classic symptoms of a failing battery that cannot maintain proper charge. In my case, the power supply system was actually fine, but the battery itself had developed internal resistance issues, leading to poor charging efficiency. Before replacing my battery, I had the workshop perform: Load testing to verify battery capacity, Charging system output verification, Battery terminal connection inspection The voltage regulator and alternator tested within spec, confirming the battery as the culprit. Since you are seeing similar idle voltage readings to what I experienced (13.2V vs normal 14.2V), it suggests your battery may also be the primary issue rather than a broader electrical problem. Replacing the battery resolved all symptoms in my case. Given our shared experience with VW electrical systems, I recommend getting that comprehensive battery diagnostic scheduled soon before the symptoms worsen.

Thank you for sharing those test results and recommendations. Your experience really helps confirm my suspicions about the battery. The voltage drop to 11.8V during startup plus the low 13.2V reading at idle definitely points to battery deterioration rather than a broader charging system issue. Since the problems get worse after sitting unused, that matches the symptoms you described of internal battery resistance problems. I just scheduled a full diagnostic for next week. Will have them perform the same battery terminal testing and charging system verification you mentioned to rule out any voltage regulator problems. The 290€ repair cost you quoted seems reasonable if battery replacement is needed. Will update once I get the results from the power supply system tests and confirm if the battery is indeed the root cause of these electrical problems. Hoping for a straightforward fix like yours rather than a more complex alternator issue.