Tonight I fixed one of my Lithium Ion battery packs which power the big light (Magicshine MJ-808) on my bike. I say fixed, but that kind of suggests I got the soldering iron out and did something substantial but it turned out that I just had to short out a couple of pins. Intentionally like, not one of those special moves where your try and kickstart it by jabbing it with a screwdriver, it was a proper co-ordinated shorting out with needle nose pliers move.
For some reason last week the battery protection circuit kicked in (I know you are wondering if that crack in the shrink wrap has anything to do with it) and disconnected the cells. The Seiko Instruments S-823 Lithium Ion Protection chip makes sure the cells don't get discharged too deeply, overcharged, or shorted out. The datasheet says you can give it a kick up the bum by shorting the VM and VCC pins together. That's pins 4 and 5, or the end ones at each side nearest the cells (see notes)
G9 is best for macro so I used that handheld with the big flash on top fitted with a Stofen diffuser to bounce the light of my nice white blind behind and ceiling. I did a slight levels tweak in and a dab of unsharp mask in GIMP and that's it.