For battery-powered components such as those used in sensor networks and the Internet of Things( IoT), energy efficiency is the top priority. The economical and economical use of battery power ensures that battery life is extended. This is the time a device can be operated before the battery needs to be changed or a battery needs to be recharged.
Battery Lifetime is determined by the ratio of stored energy to the average power drawn. The energy stored in batteries is the product of the rated voltage and the battery capacity.
There are various techniques for extending battery lifetime. These include hibernation and sleep modes, but also the reduction of the functional diversity of the end devices, the transmission bandwidth and the data rate as practiced primarily in low power WANs( LPWAN). The remaining stored energy and thus the battery life can be determined from the discharge curve. This results from the quotient of the battery capacity to the average current consumption.
As a rule, the determined battery runtimes deviate from those realized in practice, because the current drain is usually pulse-shaped, with a considerably higher transmit current and a lower current drain in receive mode and especially in sleep mode. The ratio between transmit current and sleep mode current may well be `10^6`.