For OC 3 models that are charged with 12 volts (car). Already had 3 warranty cases since April 2024! because device could not be charged via 12 volts. According to phone call with Kärcher, the problem is known there. 12-volt power supply was not sufficient to charge. I then received a new appliance after weeks. Unfortunately, it always took a long time. There were no problems with the 220 volt mains charger.