matson BT900 - ANALYZING CHARGING VOLTAGE AT IDLE

DIGITAL BATTERY TESTER
| 13BT900
SYSTEM TEST
ALT. IDLE VOLTS
xx.xx V HIGH
ALT. IDLE VOLTS
xx.xx V NORMAL
5. Press the «ENTER» key, one of the three results will be displayed along with the
actual reading measured.
HIGH CHARGING VOLTS WHEN TEST
AT IDLE
The voltage output from the alternator to
the battery exceeds the normal limits of
a functioning regulator. Check to ensure
there is no loose connection and the
ground connection is normal. If there is
no connection issue, replace the regulator.
Since most alternators have the regulator
built-in, this will require you to replace the
alternator. The normal high limit of a typical
automotive regulator is 14.7 volts +/- 0.05.
Check manufacturer specications for the
correct limit, as it will vary by vehicle type
and manufacturer.
CHARGING SYSTEM NORMAL WHEN
TEST AT IDLE
The system is showing normal output from
the alternator. No problem is detected.
LOW CHARGING VOLTS WHEN TEST
AT IDLE
The alternator is not providing sucient
current to the battery. Check the belts
to ensure the alternator is rotating
with engine running. If the belts are
slipping or broken, replace the belts
and retest. Check the connections from
the alternator to the battery. If the
connection is loose or heavily corroded,
clean or replace the cable and retest. If
the belts and connections are in good
condition, replace the alternator.
ALT. IDLE VOLTS
xx.xx V LOW