The drive system on electric bikes typically consist of a motor, controller, battery and display. Each of these components could be susceptible to water damage if not properly built or sealed. Most ebike and electric motor drive systems are built with this in mind, so the rain that serious road warriors run into won't spoil your ride.
Light rain is fine for most ebikes, but what about the heavy stuff?
Here we need to look at IP ratings. The Bafang Max motor, controller and display used on the Roadster, Trail and Attack bikes are all IP65, that means they're completely dust-proof and heavily water resistant.