This half-inch square ultra-low power energy harvesting LiPo cell charger by [Kris Winer] uses a low voltage solar panel to top up a small lithium-polymer ... features like battery health ...

Rechargeable coin cell batteries are great for all your small projects ... The circuit on this coin cell charger is built from an MCP73831, a nice single cell, lithium ion and lithium polymer ...

The battery in this charger is a 20,000 mAh lithium-ion model, enough to charge an iPhone ... “After losing power from the ice storm, I had to have a small power booster to charge my phone.