ELECTRICAL 9 FACTORS AFFECTING BATTERY LIFE: The reasons that most batteries fail prematurely are related to one or more of the following: 1. Improper charging 2.Lack of water 3. Installation 4.Operational issues NOTE The user has control over most of the conditions that lead to premature failure. 1. IMPROPER CHARGING: Over charging Charging a battery greatly in excess of what is required is harmful in several ways. Under charging A battery operated with insufficient charge over a long period of time may develop a type of sulphate in the plates which is dense, hard and crystalline and which cannot be electrochemically converted to normal active material again. A battery operated in an undercharged condition is unable to deliver the full power intended for it. Constant undercharge results in Sulphation of plates and a running down of cells. This also causes lead sulphate deposits on separators which create a short circuit between positive and negative plates. Leaving Battery Idle Causes the battery to run down due to selfdischarge. The lead sulphate crystals formed as a result of self-discharge grow as the battery stands idle and are not easily converted back on recharge. The Sulphation in other words tends to become permanent thus affecting battery capacity and lowering battery life. High Specific gravity It is destructive for both positive and negative plates to separator and shortens battery life. 2. LACK OF WATER Impure topping –up water Impure water or electrolyte introduces impurities into the battery, which accumulate with each such topping – up. The most common impurities are iron and chlorine, which attack plates and shorten overall life. This will result in higher water loss and premature failure. Neglecting topping-up De-mineralized water (DM) or distilled water is one of the four essential chemicals of a lead acid battery and under normal conditions of operation the only component of the battery, which is lost as the result of charging. It should be replaced as soon as the liquid level falls to the top of the separator. If water is not replaced plates will soon be exposed and the acid will reach a dangerously high concentration that may oxidize the separator. It further can permanently impair the performance of the plates. Plates cannot play full part in the battery reactions unless they are completely covered by the electrolyte. Acid should not be added to cells. 3. INSTALLATION: Loose Hold –downs Container damages arise from gross mishandling or dropping batteries, from hold-downs either over tightened or extremely loose. This may physically damage the plates and separators in cells or cause leakage of electrolyte so that the battery becomes unserviceable. Excessive loads A battery should never be used to propel the car by the use of the starter motor with clutch engaged except in a great emergency. This may produce extremely high internal battery temperature and may also damage the starter motor. 4. OPERATIONAL PROBLEMS Discharge without recharge A fully discharged or near fully discharged cell will be damaged and possibly ruined if not recharged within 24 to 48 hours. As a battery discharges, the electrolyte starts changing from an acid solution to almost pure water. Lead dissolves in water and some of the plate material mixes with water to form lead hydrate. Lead hydrate causes the plate surfaces to turn white and, because it is conductive it forms a short circuit between the plates rendering the battery permanently damaged. Over discharge Over discharge causes abnormal expansions of the active materials in the plates which leads to permanent damage and also recharge problems.
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