As a rule of thumb, it is generally given as 6 times the capacity of the battery. For cable-terminals, the maximum permissible discharge current is generally accepted to be approximately 3 times the capacity of the battery. Battery discharge is an electrochemical reaction between the electrodes (the plates) and the diluted sulphuric acid.
TABLE 1. MULTI-RATE, CONSTANT CURRENT CHARGING The region in Table 1 indicates a maximum current allowed of C/2 (50 amperes per 100 AH of rated capacity), and a switching voltage of 2.45 v/c. Naturally, lower currents may be used, which will reduce battery heating, resulting in greater recharge efficiency and lengthen the recharge time.
For charging the valve-regulated lead-acid battery, a well-matched charger should be used because the capacity or life of the battery is influenced by ambient temperature, charge voltage and other parameters. Cycle use is to use the battery by repeated charging and discharging in turn.
A valve regulated lead acid (VRLA) battery is also known as sealed lead–acid (SLA) battery is a type of lead-acid battery. In this type of battery, the electrolyte that does not flood the battery but it’s rather absorbed in a plate separator or silicon is added to form a gel.
However, constant current charging is not usually appropriate for the mass charge of the battery in that at these higher rates, as the battery approaches 80% state of charge, the applies voltage rises to well above 2.4 v/c, and its charge acceptance efficiency is reduced.
CAPACITY — The capacity of a battery is specified as the number of Amp-Hrs that the battery will deliver at a specific discharge rate and temperature. The capacity of a battery is not a constant value and is seen to decrease with increasing discharge rate.