Battery: Description and Operation
GENERAL DESCRIPTION
The battery has three major functions in the electrical system.First,it is a source of electrical energy for cranking the engine. Second,it acts as a voltage stabilizer for the electrical system.And third,it can,for a limited time,provide energy when the electrical load exceeds the output of the generator.
COMMON CAUSES OF FAILURE
A battery is not designed to last indefinitely;however, with proper care, it will provide many years of service. If the battery tests good but fails to perform satisfactorily in service, the following are some factors that may point to the cause of trouble:
1) Accessories left on overnight.
2) Slow average driving speeds for short periods.
3) Electrical load exceeding generator output particularly with addition of after market equipment.
4) Defects in charging system such as high resistance, slipping drive belt, loose generator output terminal, faulty generator or voltage regulator.
5) Battery abuse,including failure to keep battery cable terminals clean and tight or loose battery hold down.
6) Mechanical problems in electrical system such as shorted or pinched wires.
VISUAL INSPECTION
The external condition of the battery should be checked periodically for damage such as cracked cover or case.
BUILT-IN INDICATOR
The battery has a built-in temperature compensated indicator in the top of the battery.This indicator is to be used with the following diagnostic procedure. When checking the indicator,make sure that the battery has a clean top.A light may be needed in some poorly-lit areas.
Three types of indication available under normal operation are as follows.
1. Blue With Red Dot -or- Green Dot
Battery is ready for testing.
2. Clean with Red Dot -or- Dark
If there is a cranking complaint,battery should be tested as described in Diagnosis section.Charging and electrical systems should also be checked at this time.
3. Red With Clear Dot -or- Clear or Light Yellow
This means that fluid level is below the bottom of hydrometer. Its possible cause is excessive or prolonged charging,a broken case, excessive tipping or normal battery deterioration.When the battery is found in such condition,it is possible that high charging voltage is caused by the faulty charging system and therefore, charging and electrical systems need to be checked. If there is a trouble in cranking and its cause lies in the battery, it should be replaced.
CARRIER AND HOLD-DOWN
The battery carrier and hold-down clamp should be clean and free from corrosion before installing the battery.The carrier should be in good condition so that it will support the battery securely and keep it level.Make certain there are no parts in carrier before installing the battery.To prevent the battery from shaking in its carrier,the hold-down bolts should be tight but not overtightened.
SULFATION
If the battery is allowed to stand for a long period in discharged condition, the lead sulfate becomes converted into a hard,crystalline substance,which will not easily turn back to the active material again during the subsequent recharg mg. "Sulfation" means the result as well as the process of that reaction.Such a battery can be revived by very slow charging and may be restored to usable condition but its capacity is lower than before.
ELECTROLYTE FREEZING
The freezing point of electrolyte depends on its specific gravity.Since freezing may ruin a battery,it should be protected against freezing by keeping it in a fully charged condition.If a battery is frozen accidentally, it should not be charged until it is warmed.