The day before yesterday I gave a friend city help for his BMW. He first connected the positive poles of the batteries, then the negative poles of the batteries. His car then sprang up without any problems. During the start my car (Toyota Yaris P1, Bj 2001) was out. That means I was the dealer at the start aid. Then he stuck the cables again and we both drove off. My car jumped on without any problems. No warning lights of the amature board have lit. Today i.e. zwe i days later I wanted to use the car, but it didn’t sprung on anymore. Not even a lamp of the amature board lit, nor the driving room lighting. I have now removed the battery and could only measure 11 V voltage there. Charging just the battery and then wanted to test it again Can it be that the battery has taken damage when giving the starter aid? Why has the battery been so unloaded during a day? Can it also have other reasons for it? that the car doesn’t start after a day?