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.
∙ HYDROMETER TEST
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,
STEP 3: DO LOAD TEST
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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.
STEP 5: VIHICLE TEST
CHARGING SYSTEM DIAGNOSIS
Test and record the following:
Base voltage-engine off
Idling voltage-accessories off
2000 RPM/Accessories off
2000 RPM/ Accessories ON
CHARGING SYSTEM DIAGNOSIS INTERPRETATION
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.
STEP 6: ISSUE DISPOSITION
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.
