@rawa1234 this "very fast IA going to off" sounds more like a bad battery. Connect your multimeter to the battery cable while the charger is connected. Let us know what that voltage is. After that, you do want to check and see if the battery shows the same voltage as the charger by removing the charger. Then try to use your scooter to apply a load to the battery. If it stops working quickly, it is most likely your battery that is not holding a charge. I would most likely replace it.