Fundamentals in Battery Testing
Discover what causes batteries to fail and why testing is still in its infancy. No practical method exists to quantify all conditions of a battery in a short, comprehensive test. State-of-health (SoH) cannot be measured per se, it can only be estimated to various degrees of accuracy based on available symptoms. If the symptoms are vague or not present, a reliable measurement is not possible. When testing a battery, three SoH indicators must be evaluated: 1. Capacity , the ability to store energy 2. Internal resistance , the capability to deliver current, and 3. Self-discharge , reflecting mechanical integrity and stress-related conditions Batteries come in many conditions and a charge can easily mask a symptom allowing a weak battery to perform well. Likewise, a strong battery with low charge shares similarities with a pack that exhibits capacity loss. Battery characteristics are al...