A system for determining a state of health (SOH) of an energy storage device comprises a controller configured to be coupled to the energy storage device. The controller is configured to determine a current value drawn by or supplied to the energy storage device over a predefined period of time. In response to the current value not satisfying a current threshold, the controller determines a current gain factor and determines an adjusted current value from the determined current value based on the current gain factor. The controller is configured to determine an estimated SOH of the energy storage device based on the adjusted current value, and indicate the estimated SOH on a user interface.