Flooded lead acid battery technology is the predominant, conventional-type battery where the electrolyte is free.The name ‘flooded’ refers to the plates being immersed in an electrolyte made from 36% sulphuric acid and 64% distilled water. Flooded battery technology is used in a wide variety of applications due to its tolerance to thermal environments and ability to be maintained. Unlike VRLA batteries, hydrogen and oxygen generated during operation is not recovered, so some flooded designs require periodic watering.

Exide batteries show very little water consumption. The individual cells are no longer accessible through individual plugs, protecting against accidental acid spillage in normal motoring and so avoiding unnecessary servicing.