VW Crafter EV Power Surges Draining Battery System

As someone with moderate experience maintaining electric vehicles, I had a very similar issue with a 2018 VW e-Transporter. The symptoms you describe match what I encountered, particularly those overvoltage warnings and rapid car battery drain. After multiple electrical faults appeared, my workshop conducted a full diagnostic of the car ECU and electrical systems. They discovered the main car battery was severely degraded, causing unstable voltage output that triggered the circuit protection systems. The voltage fluctuations were affecting multiple components and creating those unusual system failures you mentioned. The repair process involved: Complete battery diagnostic testing, Checking all circuit protection components, Testing the voltage regulator, Verifying the charging system integrity, Replacing the degraded battery unit Total repair cost was 290€, which included diagnostics and parts. To provide more specific guidance for your case, could you share: The exact error codes from your diagnostic scan, How long these symptoms have been occurring, Whether the issues appear more frequently during charging, If there were any previous electrical repairs These electrical issues often have similar root causes in VW EVs, but the specific fault patterns can help identify the exact problem.

Last service was 2 months ago at 144120KM km. After thorough diagnostics, the car ECU showed pattern codes similar to what you described. The voltage regulator issues appeared gradually over 3 weeks, starting with occasional warning lights and progressing to more frequent electrical faults. The main difference is the overvoltage warnings occur mostly during regenerative braking, not while charging. No previous electrical repairs were done. Current fault codes are P0562, P0563, and U0100, suggesting power supply instability. When checked at the last service, the car battery readings were within normal range, so Im wondering if this could be related to the high-voltage system rather than the 12V circuit.

Thanks for those details, definitely helps narrow things down. Interestingly, my case also started showing problems during regen braking before the major electrical issues surfaced. Given your car ECU codes and the timing of faults during regenerative braking, this points more toward the DC-DC converter than the voltage regulator or car battery. When my voltage fluctuations appeared during regen, it was the converter failing to properly regulate power flow between the high and low voltage systems. The workshop found that while my car battery tested fine initially, the unstable power delivery from the faulty DC-DC converter eventually damaged it. The repair involved: Replacing the DC-DC converter unit, Installing a new battery management module, Recalibrating the power distribution system Total cost was around 780€ but completely resolved the electrical issues and prevented further component damage. Those fault codes combined with the regen timing strongly suggest checking the DC-DC converter first. Would recommend getting this diagnosed soon, as continuing to drive with power supply instability risks damaging more electrical components. Let me know what the workshop finds, curious if your root cause matches what I experienced with the converter.

Thanks for sharing those repair details. Super helpful to know about the DC-DC converter connection, that really matches up with what Im seeing. Scheduled a workshop visit for next week to check this specifically. The timing of faults during regen braking versus charging does make more sense now. My car ECU is showing the exact same pattern of power surges during braking that you described. Really hoping its just the converter and not more extensive circuit protection damage. 780€ is steep but still beats risking damage to other electrical components. Will update once the workshop completes their diagnosis. Between the fault codes and these specific symptoms, Im pretty confident were dealing with the same core issue. Great to hear the fix was permanent in your case. Fingers crossed for similar results with mine.