The remaining battery lifetime of IoT sensors cannot always be measured easily. Measuring the Voltage level of the battery is not accurate and not feasible for a battery which is in use with varying load . Also, the voltage in the discharge curve stays high for most of the battery lifetime until the last moment and then it suddenly drops. Therefore this is not a value or curve that can be used to predict lifetime.

Alternatively, a coulomb counter can be used like we see in phones, however for low power sensor applications this is not advised as the counter itself uses too much power reducing the lifetime of the battery or increasing cost because of a larger battery.

Aloxy decided to take another direction. The sensor uses power and the firmware on the sensor is programmed to register every activity and send this to the Aloxy IIoT Hub. In the Aloxy IIoT Hub, this is stored for every sensor and used to calculate the power consumption. An algorithm is developed to predict lifetime based on the battery capacity, the up to date power consumption and current behavior of the sensor in the network. This results in a lifetime expectation that is based on real data, it is more accurate and does not affect the sensor design.  

Network quality

When the network quality changes, and consequently the battery consumption changes, this is calculated and reflected in the battery lifetime estimate, making sure this calculation is always based on the current situation. Network quality can drop when for example sensors are added and more traffic on the network is generated or increase when a gateway is added or relocated.

The same type of sensor in the same network, however in a different location and with different usage interfaces can have a totally different lifetime and the battery would need to be swapped at a different moment in time.  

Increased efficiency, reliability and usability

Battery lifetime estimation is used to schedule battery replacements or sensor swaps and prevents loss of signal due to empty batteries increasing overall data reliability. Also, planning and scheduling battery swaps efficiently requires this kind of input to make sure batteries are not swapped either too late or too early.

The Aloxy IIoT Hub plays a critical role as the battery consumption data and the calculation is done in the IIoT Hub, it does not affect the sensor power consumption or hardware specs allowing Aloxy to strive for a low cost sensor. Additionally it is only possible to take the network performance into account because of network data that is captured by the IIoT Hub. This can also be used to learn about the quality of your network and decide on improvements in specific areas. E.g. relocating a gateway, replacing the antenna, adding a gateway, etc...

The Aloxy end-to-end solution consists of the sensor and IIoT Hub were the IIoT Hub adds some unique capabilities to provide reliable data and increase usability.  

‍