There is a need for an improved method of detecting changes in battery state-of-health. Current methods are inaccurate and lead to early battery retirement and low consumer trust due to public failures of battery management systems such as those in the Nissan Leaf. Recent developments in battery modelling suggest the potential for small signal, ultralow-frequency measurements that will allow the reliable detection of changes in battery state-of-health. To verify this method of determining state-of-health an experiment has been performed. Systematic measurement and degradation of the state-of-health of a battery through cycling, and regular measurements of the low frequency impedance, has provided conclusive evidence in support of the proposed method of detecting changes in state-of-health. For the purpose of running this experiment, and others like it in the future, tools have been developed for the systematic degradation and measurement of battery state-of-health, and for taking ultralow-frequency measurements to detect changes in state-of-health.