I’m not a huge fan of having a BMS sipping juice, as little as it may be, from my batteries whilst my electric skateboards are standing by unused.

It’s just another piece of kit that we’re allowing to fail when built into a board, susceptible to heavy vibrations, especially on urethane wheels combined with UK roads.

Hence, I decided to build an external 42V balance charger. Or rather, use a Bluetooth Battery Management System and wire this up so it can be used to charge my boards. The boards in turn, have a main power in, as well as a jst balance plug to balance the cells on.