VW Up Battery Drain: Electrical Nightmare Solutions

I had nearly identical issues with my 2019 VW Polo last winter. Having some experience with car electrics, I first suspected a simple dead battery, but it turned out to be more complex. The symptoms matched yours exactly, multiple dashboard warnings, dim lights, and the car battery would drain unusually fast even with regular driving. After attempting basic troubleshooting, I took it to my workshop where they diagnosed a faulty battery sensor. This component was causing incorrect readings and preventing proper battery charging. The repair included: Complete battery system diagnostic, Replacement of the battery sensor, Recalibration of the charging system, New battery (the old one was damaged from repeated deep discharge) Total cost was 315€ and it completely resolved the issues. The car has been running perfectly since then with no battery drain problems. Before suggesting specific solutions for your Up, could you share: Have you noticed any specific error codes? Does the battery drain happen more when parked outside or in a garage? What is the age of your current battery? Have you had any recent electrical accessories installed? This information would help determine if your issue matches the battery sensor failure I experienced or if it might be something different.

Confirming similar electrical system issues with my Up at 32969km. After the last service, I noticed the battery terminals had significant corrosion despite regular maintenance. The battery drain seemed worse in the past weeks. The mechanic found the original battery failed the load test, showing signs of internal damage. They also detected excessive current draw when the car was off, pointing to a potential parasitic draw somewhere in the system. Still getting unusual warning lights even with a new battery. Wondering if I should investigate the alternator or get a full electrical diagnostic done before throwing more parts at it. Looking at around 380€ so far with just the new battery and basic testing. Would rather identify the root cause than keep replacing parts.

Thanks for the additional details about your Up. The ongoing issues even after the battery replacement definitely mirror what I experienced. Based on your description and my similar case, I suspect your electrical problems go beyond just the battery. When my Polo showed persistent warning lights after the new battery, it turned out the alternator was only partially charging the battery. The voltage regulator inside the alternator was failing intermittently, causing inconsistent battery charging and unusual electrical system warnings. A full electrical diagnostic revealed: Alternator output was fluctuating between 12.8V and 13.9V (should be steady around 14.2V), Multiple error codes related to low voltage, Battery drain test showed 0.08A draw (normal is under 0.05A) The complete fix involved: Alternator replacement, Cleaning battery terminals and connections, Full system diagnostic and code clearing, Battery load testing to verify charging Total additional cost was 520€ but solved all electrical gremlins. The alternator was causing both insufficient battery charging and creating error codes. Since the repair, no more warning lights or battery issues for 15000km. Consider getting the alternator output tested while the engine is running. This simple check can quickly confirm if the charging system is the underlying problem causing your ongoing electrical issues.

Thanks for sharing your experiences with the vehicle battery problems. The additional symptoms after installing a new battery make me think this is more complex than initially suspected. The corrosion on the terminals despite regular maintenance is concerning. Based on what the mechanic found with the parasitic draw test and my ongoing issues, I want to focus on the charging system before spending more money. The unusual warning lights continuing even with the new battery seems to point toward either the alternator or another electrical component causing problems. I will schedule the alternator output testing and full electrical diagnostic. Better to find the root cause now than risk damaging another battery. The 380€ spent so far is frustrating, but at least we identified the initial battery failure and excessive current draw. Will update once I get the diagnostic results and voltage readings from the alternator. Really hoping to avoid throwing parts at this without confirming exactly what is causing the electrical system issues. The battery drain and warning lights need to be properly diagnosed.