IoT devices have tight requirements for power consumption in order to achieve expected battery life times of multiple years without a connection to a power supply. In order to verify the power consumption and expected battery life time, voltage and current have to be measured accurately for different operating states of the device under test. This application note explains battery life tests using RT-ZVC in combination with CMWrun and CMW500, including example applications. The solution by Rohde & Schwarz enables precise voltage, current and consequently, power measurements.