Short: fixing a rechargeable torch from Aldi

I have a quite powerful torch, which I bought a couple of year ago in Aldi. It is compact, yet provides very efficient illumination either as a beam or as a workplace illumination and has a magnetic stand.

 

I was using it and suddenly it ceased to work. No light and when trying to charge it indicated being nearly fully recharged, but never stopped charging. It was hanging around for a year or two, but finally I decided to take it apart and see what's up. It is surprisingly well built. Three screws need to be removed, as well as the front lens and the two blue panels need to be pried off. The side light and the main panel are also held in place by small screws. The whole inside can then be removed from the case.

The main parts are the battery, which includes a BMS module, the main board with the charging circuit and the light logic which operates the two separate lights and the intensity control. The push-button switch is on a separate board. Finally there are the LED modules for the front beam and the side work-light.

The battery measures 0V on the main board and very quickly I see a problem. One of the wires got pinched under one of the screw posts on the case and it seems to be broken. That is an easy fix. However, when I stripped the wire and measured voltage there, still 0V. OK, the battery may be discharged and the BMS module is shutting it off. I tried charging, but it would not take up any charge at all. I had to remove the shrink tube wrapping disconnect the BMS and charge the cell directly. It would still not respond to charging. So I'm in a strange situation that there is a broken wire and a dead cell at the same time. I don't think there is any connection (pun not intended) between them, but it might be that the cell died while being left discharged for a long time.

Since I really liked this torch, I carried on with the repair. The broken wire was reconnected and insulated with shrink tube. In the meantime I ordered a new 16850 cell with solder tabs. The BMS module got soldered to it and lacking proper size shrink tubing I wrapped it into kapton tape instead.

 That is it. Reassemble the whole thing and enjoy.