Datasheet

To make it easy to use for portable projects, we added a connector for any of our 3.7V Lithium polymer batteries and

built in battery charging. You don't need a battery, it will run just fine straight from the micro USB connector. But, if you

do have a battery, you can take it on the go, then plug in the USB to recharge. The Feather will automatically switch

over to USB power when its available. We also tied the battery thru a divider to an analog pin, so you can measure and

monitor the battery voltage to detect when you need a recharge.