Undercharged Battery

Charging Circuit - SI System:

Preliminary Checks
1. Disconnect battery ground cable.
2. Disconnect wire at BAT terminal of alternator, connect ammeter positive lead to BAT terminal and negative lead to wire.
3. Connect the battery ground cable.
4. Turn on all accessories, then connect a carbon pile regulator across battery.
5. Operate engine at moderate speed, adjust carbon pile regulator to obtain maximum current output.
6. If ammeter reading is within 10 amps of rated output, the alternator is not at fault. Alternator rating is stamped on alternator frame.

Fig. 7 Grounding Field Windings:

7. If ammeter reading is not within 10 amps of rated output, ground field winding by inserting screwdriver in end frame hole, contacting tab, Fig. 7. Do not insert screwdriver deeper than one inch, as tab is usually located within 3/4 inch of casing surface.
8. If reading is within 10 amps of rated output, regulator must be replaced. If reading is not within limits, check field winding, diode trio, rectifier bridge and stator.
9. Turn off all accessories, disconnect ammeter then carbon pile regulator.