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.
Limiting Current - The maximum current drain under which the particular battery will perform adequately under a continuous drain. The rate is based on whatever drain rate reduces the running voltage to 1.1 volts.
Shelf Life - The duration of storage under specified conditions at the end of which the battery still retains the ability to give a specified performance.
Midpoint Voltage - The voltage of a battery midway in the discharge between the start of the discharge and the end voltage.
1.5 Ah/10 = 150 mA (A cell's capacity is not the same at all discharge rates and usually increases with decreasing rate.)
Memory Effect - A phenomenon in which a cell or battery operated in successive cycles to the same, but less than full, depth of discharge temporarily loses the rest of its capacity at normal voltage levels.
COS phi - A measure of the phase shift between the current wave and the voltage wave observed at the terminals of a load supplied with AC power at a given frequency.