The effect of fast charging and equalization on the reliability and cycle life of the lead acid batteries

Three-wheeled e-rickshaws driven by lead-acid batteries are a common means of transport in Asian countries due to their low cost, and durability. Conventional charging is time-consuming and lacks proper controls for the termination of the charge. Though fast charging can significantly reduce the charging time to about one-third or less, it is prone to temperature rise, excessive gassing, and reduction in the useful life of the battery. A new fast-charging procedure along with periodic equalizing is proposed in this paper. A multistage constant current fast charger with depolarization pulse was used to charge a 48 V e-rickshaw battery pack in 3 h 37 min from 20 % to 80 % state of charge. The effect of the said fast charging procedure on the coulombic efficiency, end voltage pattern, capacity degradation, reliability, and useful life of the lead-acid batteries is investigated. Experimental results for 150 charging-discharging cycles show a temperature rise up to 5–6 °C, average coulombic efficiency of 93 %, and a maximum top-of-charge voltage of 2.6 Volts Per Cell (VPC). Attainment of such a low-temperature rise coupled with high coulombic efficiency during fast charge is the most competitive result reported for commercial batteries. A regression model and best-fit probability distribution (Weibull 3-parameter distribution) are used to estimate the degradation rate, and Cycle-To-Failure (CTF). The expected life of the batteries subjected to such a fast charging and equalizing charge is predicted to be 1296 cycles, which is about 2 times the current life of the battery. The proposed fast charger along with periodic equalizing is, therefore, a promising and sustainable option for charging lead-acid batteries. • The effect of fast charging on the cycle life of lead-acid batteries used for e-rickshaw is demonstrated. • The average coulombic efficiency of 93 %, maximum top of charge voltage of 2.6 V, and temperature rise of 5-6 oC. • The predicted life of lead-acid batteries subjected to fast charging coupled with periodic equalizing charge is 1296 cycles. • Reliability analysis is carried out to determine the gradual degradation, life, and the reliability of the lead-acid batteries