This class provides APIs to all of the registers of the Linear Technology LTC2943 battery gauge.

The caller should instantiate an I2C interface and pass this to init(), which will initialise the chip and place it into its lowest power state. Battery gauging is enabled separately. This chip is unable to determine the remaining capacity of the battery without having previously been told that the battery is fully charged and what the fully charged capacity is; the setChargingComplete() API performs this function. Once this has been called getRemainingCharge()/getRemainingPercentage() can be used to determine the remaining capacity. When battery gauging is enabled the API calls to return voltage, current and temperature will return the last reading taken. When battery gauging is disabled the chip will be maintained in its lowest power state until a voltage/current/temperature reading is requested, whereupon it will wake up, make an ADC reading and then return to sleep, taking ~300 ms to take the reading.