What charges the 12v battery

Hi @patrickcommins , as far as I know, MEB vehicles use a Hybrid Voltage Converter to step down the voltage from the main high-voltage battery to power the vehicle's 12V systems and keep the 12V starter battery charged.

Based on your question I'm assuming you're experiencing issues with your 12V battery running low. If so, the cause may not necessarily be the converter. Potential issues could include phantom loads (like a dash cam constantly drawing power from the OBD port), a weak battery, corroded wiring, or even a software glitch. If you can’t identify an obvious culprit, I would recommend consulting a professional, as diagnosing these issues can be quite the endeavour.