Overpotential-Based Battery End-of-Life Indication in WSN Nodes

Indicating the imminent battery depletion of wireless sensor nodes is beneficial for many applications. But corresponding depth of discharge estimation approaches are either complex, constraint or rather imprecise. We present, implement and evaluate a novel approach which is to observe the battery’s overpotential — the change of the voltage under a load in comparison to the unloaded battery — which increases toward the end of a battery’s lifetime. Experimental evidence that the battery’s overpotential is a better “end-of-life” indicator than the commonly used operating voltage is provided. Also, it does neither require any additional circuitry in typical sensor nodes nor significant processing overhead.