How Does a Car Battery Wear Out?by G.K. Bayne
Storing Electrical Energy
The car battery's main function is to store electrical energy for starting the car and operating devices when the engine is not running. The battery is constantly being discharged every time you start the car. It is also being constantly recharged by the car's alternator when you drive. These actions take their toll on the life of the battery.
The Parts That Never Move
All batteries for automobiles have the same, nonmoving components. Plates of lead or different materials are sandwiched together to form plates. These plates are chemically formed to store electrical current by the use of chemical action. The chemical is an acid called sulfuric acid, a highly corrosive and irritating chemical. Do to its nature, this acid is positively charged and can remain active for many years, even after the battery is declared dead. When charging, the acid deposits its positively charged electrons on the lead plates of the battery. When power is called for, the positive charges race from the plates and create a current flow. This action is repeated over and over in a closed cycle of chemical action.
The Plates Can Fall Apart
The lead plates over time can deteriorate from normal use. The constant charging and discharging will break down the lead molecules, and the plates can literally fall apart. Generally, this takes years of heavy use, so the battery is very reliable. Heat, on the other hand, is a number one cause for wearing out a battery. The lead plates of a battery are made to withstand extreme conditions, but high heat will cause the plates to fall apart inside the plastic case. Cold weather can also destroy the battery if it is not kept fully charged. A fully charged battery will have a good acid content, which can resist freezing in cold weather. If the battery is not fully charged, water is replaced in the battery, which can freeze below 32 degrees F.
Today's batteries are sealed, and you should never have to add water. In some cases, batteries do require the addition of water to keep them up to a proper level. All water that is added to batteries should be distilled water. Distilled water has the majority of the impurities removed and should only be used for the liquid recovery. If not, minerals will build up on the plates and quickly cover the plates, thus destroying their ability to be recharged.