Power Consumption and Battery Charging Characteristics of the LTC3331-Based Energy Harvesting Board for Wireless Sensor Node

Abstract

Wireless sensor networks (WSN) deployed in remote locations face a persistent energy supply challenge, which motivates the use of energy harvesting (EH) combined with battery storage to extend unattended operating life. This study characterizes the DC2509A EH demonstration board, focusing on the battery charging behavior regulated by its LTC3331 buck-boost energy harvester IC, and the power consumption of the DC2321A EH board used as the load, with a 45 mAh LIR2032 cell as the storage element. Testing combined LTspice circuit simulation with direct laboratory measurement across LTC3331 input voltages of 8 up to 18 V for two charging configurations, together with power measurements of the WSN board under four operating states. Results show that the charging current regulated by the LTC3331 increases with input voltage in the live tests, reaching an average of 4.03 mA at 18 V for the fast charge, and 0.58 mA at 18 V for the standard charge configuration. The average deviation between simulation and live measurement is approximately 2% for fast charge at 18 V, and approximately 12% for standard charge at 18 V; the latter arises partly because the simulated reference assumes a fixed battery voltage of approximately 3.78 V, whereas the physical charging current depends on instantaneous battery voltage through the path resistance. The highest power consumption of the WSN load occurred while the board searched for a network connection. These findings offer practical guidance for sizing EH-based power budgets for WSN deployments built around the DC2509A-LTC3331 platform.