This half-inch square ultra-low power energy harvesting LiPo cell charger ... battery health monitoring and undervoltage protection. [Kris] has been using the board along with a small 2.2 Volt ...

[Jay Kickliter] built his own coin cell battery recharger ... In this case he tailored the charging circuit around MCP73832 IC and chose components best suited for charging his 110 mAh LR2450.