Replacing the old battery on rechargeable bike lights

The author opened a ten-year-old rechargeable bike light, removed the circuit board, and desoldered the original battery, which was labeled “LI????77” and later identified as LIR2477. After ordering two replacement batteries from AliExpress for about $3 each and silicone glue for $8, the author soldered the new cells in, reassembled the unit with the original screws, and restored the lights.