Design and implementation of lead-acid battery state-of-health and state-of-charge measurements

In many electrical and electronic applications there is the need to have an efficient measurement over the State-of-Health (SoH) and the State-of-Charge (SoC). The SoH is an indirect measurement about the age of the battery while the SoC indicates the energy stored in the battery. The SoC and SoH are commonly referred in papers and scientific reports. However, their design and implementation procedure is very often left behind. Moreover, the implementation is not trivial. This paper presents the design and implementation of lead-acid battery SoH and SoC. The purpose is to present carefully the procedure showing how to design and implement the SoH and SoC estimators. The SoH estimation is based on obtaining the battery internal resistance. The SoC is based on the Coulomb Counting method, valid for charging and discharging processes. Experimental results using a 12V/2.3Ah battery show the efficacy of the proposed design and implementation method.