Batteries are used in PV systems to store energy and utilize it when available solar power may not be enough to power the desired load. While lead-acid batteries such as flooded electrolyte, gel electrolyte, Sealed Maintenance Free (SMF), etc. are commonly used due to lower cost and high availability, other batteries such as lithium-ion are also gaining popularity.
Batteries are sized based on power and energy requirement of the load and often oversized to provide autonomy during cloudy days. We scrutinize batteries not only in terms of energy density but also longevity, load characteristics, maintenance requirements, self-discharge, and operational costs.