Volkswagen Workshop Service and Repair Manuals

The electrolyte specific gravity test in conjunction with the battery load test provides specific information of the battery condition.

Special tools, testers and auxiliary items

• ◆ → Battery tester VAS 1979 or VAS 5033
• ◆ Observe accident prevention procedures, wear protective clothing i.e. protective goggles and leather gloves.

Note:

The load current varies and must be set on the tester according to battery capacity.

→ Performing battery load test

• ‒ Battery must be removed from vehicle .
• ‒ The battery load test should be carried out using battery tester VAS 1979 or VAS 5033.
  
• ‒ Very important:
  Connect the clips to battery terminal as described in the tester instruction manual. The clips must make good contact with the battery terminals.
• ‒ The load current varies and must be set on the tester according to the battery capacity, this can be taken from the following table .
• ‒ The minimum voltage varies, the value must not fall below this, and can be taken from the following table .

The load current and the minimum voltage varies depending upon the capacity of the battery and should be taken from the following table.

Table:

Characteristics after successfully completing battery load tests

• ◆ The battery voltage lowers (high current flow) caused by the high load (ohms resistance) during this test. If a battery is in working order the battery voltage will only sink to the lowest voltage. This varies and is dependent upon the battery capacity and the low temperature test current. Low temperature test current is understood to mean a battery power in the colder periods of the year. Batteries with a high low temperature test current are specially important for vehicles with high compression engines.
• ◆ If the battery is defective or is in a low charge state the battery voltage will drop quickly "voltage break up" voltages below 9.0V (Volt). After completing the test these low voltage values remain over an extremely long period, the voltage increases again very slowly. A usable voltage value (no load voltage) => Page 27-10 is no longer reached with such a battery.
• ◆ A battery with such faults must be noted as it no longer has the reserves of an undamaged battery.
• ◆ A battery with such a fault must be disposed of.