Harley Davidson (1970 to early 1978) Electra Glide FL/FLH-1200, Super Glide FX/FXE/FXS-1200. Service manual - page 14
CHECKING CHARGING SYSTEM
GENERAL
When the charging system fails or is not charging at a satisfactory
rate, as is visually evidenced by a weak battery and dim lights, it is
recommended that the following checks be made.
PRELIMINARY CHECKS
Battery: Check for weak or bad battery. See Battery Section. Battery
must be fully charged for following electrical tests.
Wiring: Check for corroded or loose connections in charging circuit.
Rectifier-regulator base must have a good, clean, tight connection for
proper grounding.
ELECTRICAL CHECKS
If the preliminary inspection shows components to be in good condition,
make the following electrical checks:
Regulating Voltage Check: (See Figures 5-15 and 5-16.) Connect an
ammeter in series with the alternator output. Connect load rheostat
(carbon pile) and voltmeter across battery. Check regulating voltage
while running engine at 3600 rpm.
Adjust load rheostat (or carbon pile) to 3.5 amperes output. The voltage
readings then should conform to the values given by the curves shown in
Figure 5-17 at the temperature measured at the time of testing. For
example, if the air temperature was +75°F, the upper voltage (from upper
curve) would be 15.0 volts and the lower voltage (from lower curve)
would be 13.8 volts.
Output Check: Run engine at 2000 rpm and adjust load rheostat (carbon
pile) to obtain a constant 13.0 volts. The alternator output current
should be 14 amperes minimum.
