Gikfun LiPower Shield with Mini USB Port for Arduino Uno R3 EK5002 LiPower Shield The LiPower Shield allows you to connect a 3.7V single cell Lithium polymer battery which it will boost up to 5V and connect to the Arduino boards 5V pin. The on-board MAX17043G+U IC is connected to the I2C lines (A4 and A5) so that your project can monitor its own power supply.