Auto Test BST-380, User Manual, Page: 16 / 28

The tester will start the charging volt test after an increase in rev’s is detected.
After the test is finished, the tester displays the effective charging volts, ripple test result
and charging test result.
NOTE:
If no increase in rev’s is detected, it could be the fault of generator, regulator or
connection with battery. The tester will try 3 times to further, if it still faileds, it will skip
the increase in rev’s detection and the test result displays “No Volt Output”.
Check the connection between generator and battery, then retest.
Charging Test Result:
1. Charging Volt: Normal
Charging system shows the generator output to be normal, no problem detected.
2. Charging Volt: Low
Charging volt of the charging system is low.
Check drive belt of the generator for slip or running off. Check the connection
between the generator and the battery is normal. If both the drive belt and the
connection are in good condition, follow the manufacturer’s suggestions to
eliminate generator faults.
3. Charging Volt: High
Generator output volt is high.
Since most of the vehicle generators use an internal regulator, the generator
assembly has to be replaced. (Some old style cars use an external regulator, then
directly replace the regulator.) The normal high voltage of the voltage regulator
is a maximum of 14.7±0.5V. If the charging volt is too high, it will overcharge the
battery. Therefore, the battery life will be shortened and troubles may result.
4. No Volt Output:
No generator volt output is detected. Check the generator connection cable, the
drive belt of the generator and the engine.
5. Diode Test:
Through the test of charging current ripple, the tester will find out whether the
diode is normal or not. When ripple volt is too high, it proves at least one diode is
TESTING
***
CHARGING NORMAL
LOADED 14.18V
LOADED 14.36V
RIPPLE NORMAL
NO OUTPUT
LOADED 12.81V
LOADED 12.81V
RIPPLE NORMAL