This Lipo Power shield with integrating battery monitoring and charge circuit is one of the more advance shields for powering your next mobile project. It boost the 3.7V Lipo battery input to 5V. The on-board MAX17043G+U IC is connected to the I2C lines via A4-A5 lines. The configurable alert interrupt pin on the MAX17043G+U IC is broken out to D2 which will activate when the LiPo gets to 32% or lower. The charging circuit is configured to charge the LiPo at 500mA and there is a mini-USB port on the shield which allows you to charge the battery from a USB power source.