Limitations of Batteries in Powering Wireless Sensors
Despite the tremendous advances in battery technology and the low power designs used by leading WSN sensor manufacturers, batteries do impose limitations for many customers.

1. Battery Life Degradation at Desired Sensor Update Rates & Environmental Extremes
The life of batteries powering any wireless sensors is decreased as the data update rate increases. For many customers running the update rates of their sensors at the desired level results in unacceptably short battery life. This requires them to reduce the update rate and forego the benefits of a more timely and robust data set for the monitored process or equipment. Moreover, battery life is significantly impacted by the local temperature environment. Low and high temperatures found at industrial process facilities will degrade the power the battery is able to deliver which exacerbate the life of batteries operating at high data update rates.

2. Battery Replacement Frequency
For customers who do run their sensors at the higher update rates they incur additional maintenance costs for more frequent battery replacement. Unfortunately, sensor batteries expense are only one component of the fully loaded cost of replacing them in wireless sensor deployments. Very typically the storage and special handling required of these products as well as the labor and operations disruption associated with their replacement is several times the battery costs. Over the life of the sensor can represent substantial expense and dramatically erode the ROI of wireless sensor deployments.

For many customers neither of these compromises is attractive.

3. Redundant Power Operation
There are also many instances where WSN’s are deployed in sufficiently critical monitoring environments that require very high levels of network and sensor reliability and data availability. In these applications, providing redundant sensor power capability wherein there are multiple independent power sources is a highly desired and in many cases a necessary capability. Perpetua provides solutions that uses energy harvesting and batteries to improve the assurance of long-lived data availability.