[Ampere-hour] The value is used to define the capacity of the battery. It is current in amperes, multiplied by the time in hours, during which current flows from the battery.
[Capacity] The electrical energy available from a cell or battery expressed in ampere-hours. It refers to the discharge of a constant current in a specified 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 has dropped to very low capacity levels.
[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 uses 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 recommended charge method for VRLA batteries.
[Constant Current Charge] One of the charge methods which uses current limitation. According to the charge time, some fixed amount of capacity is charged. Therefore this charge method requires the presence of devices which prevent overcharge such as a timer etc., for VRLA battery.
[Cut-off Voltage] The final voltage of a cell or battery at the end of charge or discharge.
[Deep Discharge] The discharge of a cell or battery to 80-100% of its rated capacity.
[Depth of Discharge] Frequently expressed as a percentage. It is the amount of capacity removed from a cell or battery during discharge.
[Discharge] The function of removing current from a cell or battery.
[Discharge Rate] Normally expressed as a fraction of C: it is the rate at which current is taken from a cell or battery.
[Discharge Voltage] The closed circuit voltage of a battery during discharge.
[Float] Maintains full capacity in a cell or battery by applying a continuous charge. In this instance, the load is connected to the battery and current is provided from the charger.
[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 Short Circuit]Positive plates and negative plates touch inside of the cell.
[Maintenance-Free] Secondary cells that are not sealed require periodic addition of water. Sealed Lead-Acid Batteries do not require such maintenance. Therefore they are called "maintenance free".
[Nominal Voltage] A nominal value to be used to indicate the battery voltage; for the Sealed Lead-Acid Battery; the nominal voltage is 2V / cell.
[Open-Circuit Voltage] The measured voltage of the cell or battery without a load attached.
[Overcharge] The continuous charging of a cell after it achieves 100% of capacity. The battery life is reduced by prolonged over charge.
[Overcharge Current] The charge current supplied during overcharge. Batteries can accept continuous overcharge at recommended rates and temperatures.
[Quick Rechargeability] The ability of quick charge acceptance of the batteries. Quick recharge requires not only good charge acceptability but also safety devices such as thermostat, timers, etc.
[Rated Capacity] The manufacture's rated capacity of the cell (see capacity).
[Refresh Charge] A recovery charge which is done periodically for recovering the lost capacity of batteries due to self discharge.
[Self-Discharge] The loss of capacity by a battery while in the stored or unused condition. The rate of self-discharge is affected by ambient temperature.
[Separator] The material separating the electrodes. Used to hold the electrolyte. Normally glass fiber is used.
[Shelf Life] The life of a battery when stored in the unused condition.
[VRLA] Valve Regulated Lead-Acid.