Determining the Cause of Battery Failure

Determining the Cause of Battery Failure:

Factors which are important in determining cause of battery failure are battery application, installation, service history, battery condition, and age. The answers to the following questions will aid in making an accurate determination:

Battery Application & Installation

1. Is the battery being used in the application for which it was designed, i.e. automotive, truck, tractor, bus, marine, golf cart, electric, or recreational vehicle? For example, an automotive battery used in heavy duty or deep cycle service is an obvious misapplication.


2. Is the battery sized properly for the application? Is the Cranking Performance rating at least equal to vehicle original equipment requirements?


3. Does the vehicle have excessive electrical accessory requirements, particularly those which are not original equipment, e.g. add-on air conditioning, radio, winch, or other accessories? If so, a battery with greater performance may be required.


4. Does the hold-down hardware fit the battery properly and is it properly adjusted? Does the battery's BCI group size match the vehicle's OE requirements or equivalent?


5. Do the battery cables fit the battery terminals properly and are they properly adjusted and cleaned? Have the terminals been converted from size to top terminal or vice versa and is there proper clearance for terminals from metallic parts?

Service History of the Battery:

Obtaining the service history of the battery and any history of problems from the owner may help in determining the cause of failure.

1. Has the battery been used in vehicles or applications other than the present one? Other applications may have adversely affected battery life.


2. Has the vehicle's electrical system been repaired or altered recently (very common to the cause of battery failure) and is it in proper operating condition? Charging system operation has a significant effect on battery life.


3. Has the vehicle been driven regularly or has it been parked for a lengthy period of time? Batteries self-discharge with time; extended periods of undercharge may have a detrimental effect on battery life.


4. Has the vehicle been difficult to start for any reason? Starting problems may have placed excessive loads on the battery or may indicate an undersized battery.


5. Has the battery required frequent water additions in one or more cells? Excessive water loss in all cells may indicate overcharging, a worn out battery, or both.

Visual Inspection

Visual inspection of the battery may reveal signs of abuse which may have caused failure.

1. Do the terminals show signs of having been hammered, twisted or driven down into the cover? Even minor abuse can cause internal damage.


2. Does the container or cover show signs of stress, breakage, high temperature, or vibration damage which might have caused leakage in internal damage?


3. Are the vents installed properly and are they plugged with foreign material? Improperly installed, missing, or plugged vents can be a cause of explosions, leakage or contamination.


4. Is there excessive build-up of acid or foreign material on the cover? A build-up of foreign material mixed with acid around or between the posts can cause high self-discharge rates or inadequate re-charge.


5. Are electrolyte levels below the tops of the plates in any cells? This could indicate overcharging, lack of maintenance, or internal shorts.


6. Is the electrolyte cloudy, discolored, or contaminated with foreign material? Cloudy electrolyte can indicate active material spalling due to overcharge or vibration. Electrolyte contamination can cause high self-discharge rates and poor performance.


7. Are the separators cracked or broken below the vent openings? Misuse of hydrometers or other tools could cause cell shorts.


8. Are alternate plates dark and light colored? In a charged cell, the positive plates should be dark in color and the negative plates light. If all plates are very light, severe undercharging could be indicated.

Battery Age & Date Coding

The battery's age can be an important factor in determining the cause of failure. The length of time in service determines whether the battery failed prematurely or had simply worn out. All battery manufacturers date their poduct by stamping a date code into the cover or container. This code can be used to dermin the actual age of the battery. The individual manufacturers should be consulted regarding their specific date codes.

More important is the date the battery was sold. This date determines the time the battery has been in service. The date of purchase on all battery bought at Battery Sales is indicated on a dater label with a letter and number combination, e.g. A1 would indicate January 2011.

Overcharging and Undercharging Batteries

The vehicle's charging system can have a profound effect upon the life of a battery. A high voltage regulator setting can cause excessive gassing and water loss, thermal runaway, and eventual damage to plates and separators. We often see these on vintage sports cars. This is extremely common when replacing a lead-acid battery with a sealed gel battery. Gel batteries are constantly being overcharged and failing because of the voltage regulator. If the voltage regulator setting is too low, there is a high resistance in the charging circuit, or the charging system is not capable of handling the accessory load the battery will be in a constant state of discharge. If this happens over a long period of time, the sulfate which deposits on the plates can become hard and crystallize. In this form, the plates may not accept a charge under normal conditions and may even cause short circuits through the separators due to a build-up of lead sulfate through the pores which is converted to lead shorts during recharge.

Voltage regulator settings vary among vehicle manufactures and may not be adjustable. They should be checked with the indivdual manufacturer before adjustment is atempted. Different battery types using different grid alloys and manufacturing processes may require different charging methods; this includes Lead Acid Batteries, AGM Batteries, and GEL Batteries.