A Straightforward Method to Estimate Battery's Condition Based on Its Internal Resistance Value

Abstract

A battery condition monitor can be realized using several methods. Some of these methods have been proven to be more reliable than others. In this study, we focus on assessing a battery's condition based on its internal resistance value using a direct current method (DCM). We developed a simple, fast, and straightforward method, including the necessary equipment for this purpose. Only measurements of the battery's terminal (open-circuit) voltage and battery voltage under a certain load are required. We measured around 100 non-rechargeable AA batteries (double-A batteries) and estimated their internal resistances. Both alkaline and lithium-based batteries were tested. Our measurements show that measuring the terminal voltage (open-circuit voltage) alone does not provide an accurate enough status of a battery's condition or state-of-health, SoH. Especially when the battery condition is declining, the internal resistance value gives a better estimation of the battery's condition and usability.