The Rosenberger connection of the charger plug, the charging connection on the down tube at the top and the battery socket on the battery or in the battery compartment at the bottom provide a good connection during operation. It is magnetic and can be easily disconnected or connected. It is not immune to moisture/water, even in the battery compartment.
Possible causes
Moisture and water in combination with electricity cause corrosion. Small metal parts can be deposited between the contacts. Both lead to leakage currents or even short circuits. The four small pins that provide +/- 12 V and the CAN bus connection are particularly affected. If you then try to improve the contact properties with a contact grease or spray, you will achieve the opposite.
