The m-3 is my third ebike but the 7 th one I’ve bought. Friends and family have been curious about my new hobby and caught the ebike fever . I like the active fan in the charger , that’s a first . I’m not so excited about not being informed my second battery(20-ah) won't be interchangeable with the 15 ah. Can’t use both without changing the rail. You done even offer a jumper cord that would reach the rack stowed battery