Adafruit LiIon/LiPoly Backpack Add-On for Pro Trinket/ItsyBitsy

The LiPoly Backpack for ItsyBitsy and Pro Trinket is a compact, efficient solution for adding portable power to your projects. This small, easy-to-use PCB sits atop your Pro Trinket or ItsyBitsy board and makes it simple to integrate a rechargeable LiPoly or LiIon battery. When the USB port of the Pro Trinket or ItsyBitsy is powered, the backpack automatically recharges the connected battery. Once the USB port is unplugged, the microcontroller seamlessly switches to the battery power.

Key Features:

• Ideal for 3.3V Boards: This backpack is designed for use with 3.3V Pro Trinkets & ItsyBitsys, where the 3.7V to 4.2V battery voltage is regulated down to 3.3V for stable operation.
• Battery and Microcontroller Integration: This system allows the use of a single LiPoly/LiIon battery (3.7V-4.2V) to power your project without the need for multiple boards and wiring.
• Simple Charging and Power Switching: The backpack manages automatic charging and power switching between the USB and battery. The red LED indicates charging, while the green LED shows when the battery is fully charged.
• Optional On/Off Switch: You can easily add an On/Off switch by modifying the battery output line and cutting the trace between the two holes on the PCB.
• Three-Stage Charging: The charger follows a three-stage process: preconditioning, constant-current fast charge, and constant-voltage trickle charge, ensuring efficient and safe charging for your battery.
• Adjustable Charge Current: By default, the charge current is 100mA, but you can increase it to 500mA for larger batteries by soldering a jumper on the bottom.

Specifications:

• Battery Compatibility: For use with Adafruit LiPoly/LiIon 3.7V/4.2V batteries only. Other battery types may not be compatible.
• Dimensions: 15mm x 17mm x 2mm / 0.6" x 0.7" x 0.08"
• Height with JST connector: 7mm / 0.3"
• Weight: 1.3g
• Charging Current: 100mA (adjustable to 500mA)
• Includes: Assembled and tested LiPoly Backpack (batteries, Pro Trinket, and ItsyBitsy not included)

Note: For the Itsy nRF52840, the backpack may cover the reset/user buttons. You can use wires to connect the buttons instead of placing the backpack directly on top.

Make your portable projects simpler and more efficient with this easy-to-use LiPoly backpack!