POWER PLAY are Arduino based smart power monitors that are used to measure and optimize the power consumption of battery operated devices such as smart phones.
This model provides the most accurate results but requires modifying the tested device. The POWER PLAY 3.8V outputs regulated 3.8 volts are simulates the power provided by a single cell Li-Ion battery cell. It requires disconnecting the battery from the tested device and hooking the output of the POWER PLAY 3.8V instead.
POWER PLAY – Arduino based smart power monitors – [Link]