Make sure that the battery is properly cooled down before making this test.  

Battery just taken out from charging will give misleading voltage reading.  

For battery installed on vehicle, remove surface charge by turning-on  

headlight for 15 seconds with engine off. 


Check water level. 

Electrolyte from battery must be clear to opaque in color. Muddy electrolyte  

denotes that plates have shed.  

Any other color points to contamination. 

Charging this battery will give off a very offensive odor. 

Cell reading must not have more than 50 points difference. 

Normally, cell with the lowest reading is investigated first, 


Ensure that battery was charged or an attempt to recharge was done before doing this. LOAD TEST RESULT INTERPRETATION: 

SHORTED CELL: Shortening of electrical path, which results in a greater than normal rate  of discharged and/or reduction in cell voltage under load. Can be detected by presence of  bubbles or smoke in the shorted cell during load testing, specific gravity will be very low  usually 1.100 sg ( specific gravity ) 

OPEN CONNECTION: No electrical continuity as indicated by zero open circuit voltage  (0 volt) 

LOOSE CONNECTION: with electrical continuity but with open circuit voltage reading during  load test (12 volts-0volt) 

REVERSE ASSEMBLY: Incorrect connection of (+) & (-) of cells, can be detected by an open  circuit voltage of less than 12 V. 

EXCESSIV LOSS OF ELECTROLYTE: electrolyte level is below top of the plates or not visible  at all. Electrolyte is normally higher than 1.300 sg 

SULFATED PLATES: the battery is discharged with open circuit voltage ( O.C.V ) of 12.0 V or  lower. The plates are pale, hardened, sometimes with visible whitish  

materials particularly on positive plates. Electrolyte is expected to  have Low Specific Gravity (s.g) on all cells (<1.200sg.). The  battery was left in deep discharged condition and the plates become  sulfated. 

OVER –ACID: Indicates very high electrolyte specific gravity and voltage due to presence  of more sulfates. This is determined to life of the battery. Electrolyte will   be muddy because the negatives are expected to have soft active materials.



Test and record the following: 

Base voltage-engine off 

Idling voltage-accessories off 

2000 RPM/Accessories off 

2000 RPM/ Accessories ON 


BASE VOLTAGE-With the engine off and surface voltage removed, take a voltage reading of the battery, this normally ranges from 12.0 to 12,7 volts on a well charged battery. If the  base voltage you get reads as low as 10.5 to 11.0 volts you can proceed with the test but you  would certainly want to suspect the battery if the charging systems checks is okay. 

START UP THE ENGINE WITH NO LOAD-Make sure that no load is open. Rev it up to 2000 RPM or something to then amount of pressure you apply on the gas pedal when you drive.  At this point, the alternator must be operating at full output. Take another voltage reading.  It should not be more than 2.0 volts above the base voltage. Any higher means  overcharging. 

At the base voltage of 12.50, the maximum no load voltage is 14.5 volts. If you get a  Voltage reading 0f 15.0 volts, the vehicle is overcharging and will cause excessive gassing  of battery. 

REV UP TO 2000 RPM WITH FULL LOAD- With the engine still on, rev it up again to 2000 rpm  or so and turn on the car’s heaviest loads as aircon, headlights, etc.. Take a voltage  reading. The figure you’ll get is the load voltage and must be at least 0.5 volts above the  base voltage. Any value less, you’re undercharging. 

At he base voltage of 12.50, the minimum no load voltage is 13.0 volts. If you get a voltage  reading of 12,5 volts, the vehicle is under-charging and will cause draining of battery  power. 

The factors +2.0 volts and 0.5 volts allow for safely margin. If the charging system checks out  within these values, you can be pretty sure that vehicle charging system is working just fine and  doing its job. 


Make decision on clam is a business necessity. Thus, you must be able to determine the real  cause of defect, whether Factory defect or Non-factory defect, and ready to explain to  customer the reason for denied of claim if ever the need arises.

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