Testing a standard and low maintenance battery
Note: Some vehicles are equipped with sealed batteries that are not serviceable and cannot be checked for electrolyte density. The condition of such a battery can only be checked by measuring the voltage at the battery terminals.
If the vehicle has a low annual mileage, it is recommended to check the electrolyte density every three months to determine the battery's state of charge.
The density of the electrolyte depends on temperature, so to convert the measured density value to the density at 20°C use the following formula.
D20 = Dt + 0,0007 (t - 20),
where:
- D20: density of electrolyte reduced to 20°C
- Dt: the result of the actual density measurement
- t: actual temperature of electrolyte
The density of the electrolyte, reduced to a temperature of 20°C, of a fully charged battery should be within the range of 1.250-1.290 g/cm³.
If you suspect that your battery is faulty, first check the density of the electrolyte in each section of the battery. A difference in electrolyte density of more than 0.040 indicates loss of electrolyte or deterioration in the quality of the internal plates.
If the difference in electrolyte density exceeds 0.040, the battery must be replaced. If the difference in electrolyte density between the battery sections is less than this value and the battery is discharged, it must be charged.
Testing a Maintenance Free Battery
If the vehicle has a sealed battery, it is not possible to check the density of the electrolyte or add it. Therefore, the condition of such a battery can only be checked using the built-in condition indicator or a voltmeter.
One type of maintenance-free battery that can be installed in a vehicle is a battery that has a built-in status indicator. The indicator is located on top of the battery case and indicates the battery status by changing its color. If the indicator is green, the battery is sufficiently charged. If the indicator darkens, gradually turning black, it means the battery requires charging. If the indicator is clear/yellow, the electrolyte level in the battery is too low and the battery needs to be replaced. Do not attempt to charge, load, or jump start your vehicle with a booster battery if the battery indicator is clear/yellow.
When testing the battery with a voltmeter, connect the voltmeter to the battery terminals and compare the results with the data given in the "Technical Specifications". The test will only give correct results if the battery has not been charged within the previous six hours. If the battery has been recharged, turn on the headlights for 30 seconds, then wait four to five minutes after turning off the headlights before beginning the test. All other electrical circuits must be switched off, so make sure the doors and trunk lid are closed when performing the test.
If the voltmeter reading is less than 12 V, it means that the battery is discharged; a voltage of 12.0-12.4 V indicates that the battery is partially discharged.
If the battery needs to be recharged, remove it from the vehicle and charge it.
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