I have a couple Cygolite HotShot tail lights (80 & 150 lumen). The battery failed on the 'Pro' (150 lumen) one. When plugged into USB it just stays on constant rather than the pulsing for normal charging and when unplugged it is totally dead. I swapped batteries with the '80' to verify that the battery is the problem - and I'd rather have the newer 'Pro' be the one that's working.

Wondering if anyone knows a reasonable source for a replacement battery so I could get the '80' working again. It's a Li-ion cell with 830 mA-hr capacity and has a connector at the end of a short 3-wire cord.

Circuit board showing cord and connector:

View of battery from underneath circuit board: