An enhanced coulomb counting method for estimating state-of-charge and state-of-health of lead-acid batteries

This paper proposes an enhanced coulomb counting method based on the depth-of-discharge (DOD) to estimate the state-of-charge (SOC) and state-of-health (SOH) for valve regulated lead-acid (VRLA) batteries. The losses at different discharging currents are accounted for compensation to the releasable capacities. Furthermore, the SOH is revaluated at the depletion and fully charged states by the maximum releasable capacity and the charged capacity, consequently leading to more accurate SOC estimation. Through the experiments that emulate practical operations, the experimental results reveal that the maximum error is less than 6 %.