Moin To the problem: the battery is not charged and therefore constantly vacuumed by the consumers. For troubleshooting I lack the schematic with the one of the same ATU scooter I really can’t get any further. So far it has been done: controller changed 3 times new 2 times for another scooter. Cable harness changed. Lima changed. Battery changed. With spare cable from controller to battery bypass. So everything that has to do with it somehow. e after a few days with empty battery again. I run out of ideas! Many times a technically experienced Forian has already solved an idea or a similar problem. The last measurement resulted in controller input 14 volt output 13.4 volt output AC voltage, and no matter which of the 5 controllers you connect between 2 and 6 volt output DC voltage. The probability of 5 broken controllers goes against 0. So what’s the problem?