Start the engine. Voltage may drop to 8V during startup (at ambient temperature +20°C).
Accelerate the engine to 3000 rpm. The voltage should reach a value of 13.5 to 14.5 V. This indicates the normal operation of the generator and voltage regulator. The alternator voltage must be higher than the battery voltage so that the battery is charged while the vehicle is running.
Check the stability of the adjustment. Why turn on the high beam and repeat the measurement at 3000 rpm. In this case, the voltage should not decrease by more than 0.4 V compared to the previous value.
If the generator voltage is too low
Check the electrical connections of the generator for tight fit and contact quality. To do this, disconnect the wires and inspect the contact surfaces. Reinforce the wires on the generator.
Check all thick B+ wire connections from the alternator to the positive battery terminal for tightness and contact quality.
Check the tightness and quality of the connection of the negative wire from the battery to the body, removing, if necessary, traces of corrosion.
Check the wire connections on the battery.
If no defects are found, check the contact brushes or have the generator repaired in a workshop.