[ VRLA ]
Abbreviation of Valve Regulated Lead-Acid.

[ Maintenance-Free ]
Secondary cells that are not sealed require periodic addition of water. Sealed Lead-Acid Batteries do no 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.

[ Internal Short Circuit ]Positive plates and negative plates touch together through at the inside of the cell.

[ Life ]
The time period until the battery can no longer be used because it has lost its characteristics.

[ Load ]
A device or mechanism external to a battery, and which is powered by the battery. The resistance of the load and the battery voltage dictate the current flow rate, and thus the run time for the battery.

[ 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.

[ Vent ]
Pressure-relief valve in a cell or battery that allows for the escape of gases at some release pressure but does not allow any level of gas ingress.