Powell is right-Think through what you are going to do before you get into it. I cut a cover for the BMS board out of a plastic milk jug to help prevent anything from falling onto the board while power was still present. I also put jumpers across the connection point until I had the screws out, then put a plastic shim between the terminal contact surfaces. Pulling off the jumpers allowed a clean disconnect at that point. The hard part is that there isn't much room to place a jumper.