The battery is the vehicle’s initial source of energy used to start the engine. The battery is then taken over the alternator to supply the car’s electrical needs and to restore energy to the battery. A 12-volt storage battery consists of layers of positively and negatively charged lead plates that, together with their insulated separators, make up each of six two-volt cells. The fluid in the cells are electricity-conducting liquid (electrolyte) that is usually two-thirds distilled water and one-third sulfuric acid. Spaces between the immersed plates provide the most exposure to the electrolyte. The interaction of the plates and the electrolyte produces chemical energy that becomes electricity when a circuit is formed between the negative and positive battery terminals.
Use and maintenance
Refill the battery, when needed, with distilled water. The level must be maintained so that it is just touching the bottom of the refill hole, without overfilling.
Charge and discharge
There are several different methods used to recharge a depleted battery. The most gentle of these is called trickle-charging. Other methods include slow-charging and quick-charging, the latter being the harshest.
Changing a battery
In the vast majority of automobiles, the grounding is provided by connecting the body of the car to the negative electrode of the battery, a system called ‘negative ground’. In the past this was different, some cars had ‘positive ground’.
When removing a car battery, the ground connection should be removed first and the other connection second. This ensures that a short circuit will not occur by a wrench touching grounded engine parts while disconnecting the other terminal. When connecting a battery, connect the live connection first and then the grounded one.
Because of “sulfation” (see lead-acid battery), one should never buy a battery that is more than six-months old. In the United States, the manufacturing date is printed on a sticker. The date can be written in plain text or using an alphanumerical code. The first character is a letter that specifies the month (A for January, B for February) with I being skipped. The second character is a single digit that indicates the year of manufacturing (for example, 5 for 2005).