[ Ampere-hour ]
A standard unit for measuring the quantity of electricity, equal to the flow of a current of one ampere for one hour

[ Available Capacity ]
The capacity available from the battery based on its state of charge, rate of discharge, ambient temperature and specified cut-off voltage.

[ Battery set]
Two or more cells, connected together, normally in series. At times, a single cell may be referred to as a battery.

[ Capacity ]
The electrical energy available from a cell or battery expressed in ampere-hours. It refers to the discharge of a constant current for a measure time to a specified cut-off voltage (normally 1.75V /2V cell), at a specified temperature.

[ Capacity Recovery ]
Also called recoverable capacity. This is the discharge capacity that can be restored to a cell or battery through various treatments when it had dropped to very low capacity levels.

[ Cell ]
The minimum unit of the battery that composes a storage battery; the nominal voltage of a cell of the Lead-Acid Battery is 2.0V. Most batteries are made of 2 or more cells. Typically 3 cells for a 6Volt, and 6 cells for a 12Volt battery.

[ Charge ]
The process of restoring electrical energy to a cell or battery, in the process increasing the cell voltage.

[ Charge Efficiency ]
Ratio of the ampere-hours delivered during discharge divided by the ampere-hours put into the battery during recharge.

[ Constant Voltage Charge ]
One of the charge methods which has voltage limitation. When the discharged battery is charged by this way, the charge current is reduced automatically according to the state of charge. This is the most recommendable charge method for VRLA batteries.

[ Constant Current Charge ]
One of the charge methods which has current limitation. According to the charge time, some fixed amount of capacity is charged. Therefore this charge method requires some devices which prevent overcharge such as timer etc., for VRLA battery.

[ High-rate Charge/Discharge ]
Charge / discharge processes that are carried out at relatively high current densities, with the multiple of C rate depending upon the battery design.

[ Internal Impedance/Resistance ]
A measure of a cell’s electrical resistance to current flow, resulting in small or large voltage drops and some level of resistive heating. Impedance (AC) and resistance (DC) values are proportional but different, resulting from differences in measurement methodology.