Impedance
The apparent resistance in an A.C. circuit.

Industrial battery
A storage battery which is used to supply power to industrial equipment (e.g. fork-lift trucks, wheel chairs, etc.).

Inner resistance
Ohmic resistance of a battery.

Inner resistance, effective
The measurable resistance against the flow of current in a battery expressed as a drop in the battery voltage proportional to the discharging current.
The value is dependent on the manner of construction, the charge state, temperature and the age of the battery.

Insulation resistance
Insulation resistance is the resistance between a cell or battery and a mass/earth (motor-vehicle body, torso).

Insulator
>> Separator.

Ion
Charged atom our group of atoms which transport electricity through the electrolyte.