profezzorn, TeensySaber board V2 had only one ground connection, the battery-, but the V3 board has battery- and a wire connection to the GND pin. Why? We are doing a group build and have a mix of V2 and V3 boards and this GND connection tripped us up (spend a good hour trying to figure out why the V3 board would work with only battery+ and battery- connected, of course it came right up when we connected a wire from battery- to GND). Is it to accommodate different ways of powering the saber? Anyway, I recommend adding a zero Ohm resistor to the PCB design to eliminate the need for the wire from battery- to GND, it would be cleaner and users would have the choice to load the zero Ohm resistor or not.