Investigation of the Impact of AC Harmonics on Lead Acid Battery Degradation

The increasing number of battery-operated electric vehicles and machines has raised concerns about the effects of harmonics rising from the charging point on the degradation of batteries. Lead acid battery stands as one of the most established types of battery used by the consumer. Although it has a low energy density, it is the most commonly used battery due to its accessibility and affordability. In Bangladesh, lead acid battery is frequently used in electric rickshaws, UPS, and household machinery. Taking the rising concern regarding AC ripples affecting battery health into consideration, in this research, we have performed a detailed experimental investigation on the effect of multiple different frequency harmonics on gel-type lead acid batteries. Frequencies of 100Hz, 1kHz, and pure DC have been tested on the lead acid batteries. The experimentation is conducted for 35 cycles in constant current charging conditions until a significant change in battery performance has been observed. The degradation is analyzed against multiple parameters, such as internal resistance and discharge capacity, for a higher accuracy verdict. The effect of AC harmonics on battery degradation is identified to be more prominent at the lower frequency of 100Hz as the internal resistance increased from 71mΩ to 96mΩ and the discharge capacity reduced from 3.682Ah to 2.721Ah. The significant changes in both parameters indicated accelerated aging and degradation in the battery charged at 100Hz.