Operating temperature of the battery has a profound effect on operating characteristics and the life of a lead-acid battery. Discharge capacity is increased at higher temperatures and decreased at lower temperatures. At higher temperatures, the fraction of theoretical capacity delivered during discharge increases.
However, due to the corrosive nature the elecrolyte, all batteries to some extent introduce an additional maintenance component into a PV system. Lead acid batteries typically have coloumbic efficiencies of 85% and energy efficiencies in the order of 70%.
A deep-cycle lead acid battery should be able to maintain a cycle life of more than 1,000 even at DOD over 50%. Figure: Relationship between battery capacity, depth of discharge and cycle life for a shallow-cycle battery. In addition to the DOD, the charging regime also plays an important part in determining battery lifetime.
Lead acid batteries typically have coloumbic efficiencies of 85% and energy efficiencies in the order of 70%. Depending on which one of the above problems is of most concern for a particular application, appropriate modifications to the basic battery configuration improve battery performance.
A finishing rate of 5 A per 100 Ah end-of-charge voltage for newly produced cells can vary from 2.5 to 2.90 volts at 25°C depending upon the cell design and composition of the grids and the active materials. As battery life progresses the end-of-charge voltage for pure lead and lead-calcium cells remains essentially constant.
The production and escape of hydrogen and oxygen gas from a battery cause water loss and water must be regularly replaced in lead acid batteries. Other components of a battery system do not require maintenance as regularly, so water loss can be a significant problem. If the system is in a remote location, checking water loss can add to costs.