Depth of Discharge
The ratio of the quantity of electricity (usually in ampere-hours) removed from a battery to its rated capacity.

Desorption
The opposite of absorption, whereby the material retained by a medium or another material is released.

Direct Current
Electrical current that flows in one direction only. Batteries produce direct current as the current flows from a negative to a positive source.

Discharge
The conversion of the chemical energy of a battery into electrical energy, and the withdrawal of the electrical energy into a load.

Discharge Rate
The rate, usually expressed in amperes, at which electrical current is taken from the battery.

Drain
The current withdrawn from a battery during discharge.

Dry Cell
A cell with immobilized electrolyte. The term "dry cell" is often used to describe the Leclanche cell.

Dumb Battery
Straight battery pack without internal circuits enabling communication between the battery and the user.

Duty Cycle
The operating regime of a battery including factors such as charge and discharge rates, depth of discharge, cycle duration, and length of time in the standby mode.