Hi. My BB 2 Backpack just stopped working (My BB 1 did the same so I just bought the BB2). Took it apart and checked everything and all wires seemed ok, fuse was ok , cleaned the fuse contacts, so assumed it was the battery . Then I tried to power on while attached to charger and it still wouldn’t work! Could be a broken wire, could be broken controller or rocker switch or even charging point……I’m thinking that’s me spending another £175!!! Then I checked the spring on one side of the fuse cable and it was broken! So I took a spring from a ball point pen and wound it onto the wire, initially too strong so cut a few winds off and BOOM….all working again! Just thought I’d post as it might help someone else.