Specific Energy - The ratio of the energy output of a cell or battery to its weight (Wh/kg). This term is used interchangeably with gravimetric energy density.
Passivation - The phenomenon by which a metal, although in conditions of thermodynamic instability, remains indefinitely unattacked because of modified or altered surface conditions.
Charge Control - Technique for effectively terminating the charging of a rechargeable battery.
Parallel - Term used to describe the interconnection of cells or batteries in which all the like terminals are connected together. Results in increased capacity.
Self-Discharge - The loss of useful capacity of a battery on storage due to internal chemical action (local action).
Inverter (off-line or stand-by) - UPS configuration in which the inverter is parallel-mounted to the load supply line and backs up the mains. This configuration offers a substantial cost reduction but is applicable only to low outputs, under 3 kVA, because it results in an interruption lasting up to 10 ms during transfer and does not filter inrush currents.
Voltage-Keyed - A system which incorporates a mechanical identifier on batteries and devices to ensure only batteries of the correct voltage are connected to the device.