Datasheet

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

Here's some handy specs! Like all Feather 32u4's you get:

Measures 2.0" x 0.9" x 0.28" (51mm x 23mm x 8mm) without headers soldered in

Light as a (large?) feather - 5.7 grams

ATmega32u4 @ 8MHz with 3.3V logic/power

3.3V regulator with 500mA peak current output

USB native support, comes with USB bootloader and serial port debugging

You also get tons of pins - 20 GPIO pins

Hardware Serial, hardware I2C, hardware SPI support

7 x PWM pins

10 x analog inputs

Built in 100mA lipoly charger with charging status indicator LED

Pin #13 red LED for general purpose blinking

Power/enable pin

4 mounting holes

Reset button

The Feather 32u4 Bluefruit LE uses the extra space left over to add our excellent Bluefruit BTLE module + two status

indicator LEDs