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26-10-2010, 12:04 PM
Autotronics Notes.pdf (Size: 3.99 MB / Downloads: 140)
Requirements, construction, principle of operation and working of the following
types of batteries: Lead acid, Alkaline, ZEBRA, Sodium Sulphur and Swing battery.
Ratings, charging, Maintenance, and testing of Lead-Acid battery.
1.1) Battery Requirements
The vehicle battery is used as a source of energy when the engine, and thus the
alternator are not running. The battery has a number of requirements they are as
To provide power storage and be able to supply it quickly enough to operate
the vehicle starter motor.
To allow the use of parking lights for automobile for a reasonable amount of
To allow operation of accessories when the engine is not running.
To act as a swamp to damp out fluctuations of system voltage.
To allow dynamic memory and alarm systems to remain active when the
vehicle is left for some time.
The battery should carry out all the above in a temperature range, usually
from -30oC to +70oC.
1.2) The Lead Acid Battery
The basic construction of a nominal 12 V lead acid battery consists of six cells
connected in series. Each cell, producing 2 V, is housed in an individual compartment
with a polypropylene, or similar case. The active material is held in grids or baskets to
form positive and negative plates. Separators made from micro porous plastic
insulate these plates from each other. The grids connecting the strips and the battery
posts are made of lead alloy. For many years this was lead antimony (PbSb) but lately
it has been lead calcium (PbCa). The newer materials cause less gassing of the
electrolyte when fully charged. This is one of the main reasons why sealed batteries
became usable as the water loss was considerably reduced. However, even modern
batteries have a small amount of vent to release the little pressure that builds due to
the little gassing.