12V battery problem?

[Pascal]

I bought an Mg HS PHEV on 21 nov 2025. Yesterday, it was dead. I had charged it overnight, but in the morning, I couldn’t unlock the doors, nor could I unplug the charging cable. I contacted the dealer 2km away, but he refused to send a technician. I had to Vaal the MG road assistance. They came and told me the 12B battery was faulty. Immediately went to the dealer. He checked the car and told me there was nothing wrong with this battery. If I wanted anew one, I would have to pay for it myself. He didn’t bother checking what caused the total breakdown of the car and that was it! There could be some kind of leak in the electric circuit, or the alternator could be malfunctioning. Has anyone had this kind of problem and how was it fixed?

 

[HStrophyPHEV2025rc]

Yes, others have reported a flat 12v battery in this forum. I suggest you read these threads:

• MG HS Hybrid battery drain
• Battery drain again

From what I can tell, it seems that some cars have faulty infotainment screens where the backlight does not switch off overnight (they look 'grey' not truly black at night) so they constantly draw power.

 

[Totti1001]

As already mentioned, the first models had faulty displays that were constantly lit.
In my case, it was the light/rain sensor next to the camera. It was constantly heating up, melting even 10 cm of thick snow. The 12 V battery was empty after three days.
The car was then in the workshop for seven days. Apparently, only the software for the BCM was reinstalled. I can't say whether that was really the reason, but since then the voltage of the 12V battery has remained stable. V