At present, most automotive generator regulators are electronically integrated and can operate reliably as long as the wiring is correct.
You can use a multimeter to perform the following tests:
1. Check that the battery is not losing power and, with the engine running at medium speed, measure the battery voltage. be between 27.6 and 28 V, greater than 28 V, indicating that the regulator has failed and must be replaced.
2. Check that the battery is not losing power and that the battery voltage is between 27.6 and 28 V when the engine is running at medium speed. If the bulb still burns, it means it is of poor quality.