Operation CHARM: Car repair manuals for everyone.

Undercharged Battery

This condition, as evidenced by slow cranking can be caused by one or more of the following conditions even though indicator lamp may be operating normal.

Following procedure also applies to cars with voltmeter and ammeter.
1. Make sure that undercharged condition has not been caused by accessories left on for extended period of time.
2. Check drive belt for proper tension.
3. If battery defect is suspected, refer to Battery.
4. Inspect wiring for defects. Check all connections for tightness and cleanliness, battery cable connections at battery, starter and ignition ground cable.




5. Connect voltmeter and ammeter as shown in figure.

Voltmeter
Set between generator B terminal and ground.

Ammeter
Set between generator B terminal and battery (+) terminal.

NOTE: Use fully charged battery.

6. Measure current and voltage.

No-load Check







1. Run engine from idling up to 2,000 rpm and read meters.

NOTE: Turn off switches of all accessories (wiper, heater etc.).

NOTE: Consideration should be taken that voltage will differ somewhat with regulator case temperature as shown in figure.

Higher Voltage
If voltage is higher than standard value, check ground of brush.
If brush ground is correct, replace IC regulator.

Lower Voltage
If voltage is lower than standard value, proceed to following check.




2. Ground F terminal and start engine, then measure voltage at B terminal as shown in figure.
- Voltage is higher than standard value
It is considered that generator itself is good but IC regulator has been damaged, replace IC regulator.
- Voltage is lower than standard value Generator it self has problem, check the generator.

Load Check
1. Run engine at 2,000 rpm and turn on head light and heater motor.
2. Measure current and if it is less than 20A (Type A) or 30 A (Type B), repair or replace generator.