One battery is replaced every year, three in a row, and it is still on the road twice. Later, emergency starting power supply is always available. Recently, I really wanted to solve this problem. The battery often lost power. I found that the battery in the car was never charged (the voltage was 12.6 volts). When the negative sensor was pulled out, the voltage increased to about 14.6 volts, and I was worried about overcharging. The negative sensor was also replaced before and after (Car Removal 350), and the problem remained unchanged. I sent a post for help, thanking xuser19452979 and Yan Ban for the solution. I went to Lixing Hang for maintenance today and received the car and described the phenomenon. I wanted to communicate with the master in the workshop, but the epidemic was not allowed to enter. I waited in the lounge for 3 hours. I watched the master keep measuring with an electricity meter and began to remove the door panels. It seemed that I had been looking for a leakage point. There were fewer and fewer cars in the maintenance workshop. Three or four maintenance masters surrounded me and couldn’t find the reason. There was no way to rush into the workshop to communicate with the master, saying that the battery’s loss of electricity and its durability had nothing to do with leakage of electricity. The official Mercedes-Benz issued an announcement to upgrade the sam program before and after the upgrade. The master said it was impossible. He had never encountered it before. The power consumption of your car seems to be slightly higher, but he still follows his own ideas. I couldn’t help it. I said I had no problem taking a taxi after stopping for two or three weeks. At present, the voltage came up after unplugging the negative induction wire. When I plugged in the voltage, it was 12.6 and I didn’t charge it. What I wanted to solve was the problem of not charging. I showed him a strict version of the reply. Only then did the master believe it and became suspicious. SAM only took 20 minutes before and after the upgrade. After the upgrade, the negative induction wire was plugged in when the car was parked, and the voltage returned to normal, which was a perfect solution. I took a look on the way back. When accelerating or at a constant speed, the voltage was 12.6 volts, and the oil collection rose to about 13.8-14.6. It’s definitely different from the previous 12.6. Maybe it’s charging logic. Keep observing. In the same situation, we advise everyone to directly tell the 4S shop about the SAM procedures before and after upgrading, although many maintenance technicians in the 4S shop have experience and no clear solutions.