Cummins/Onan — Battery Charging Winding Tests
Testing & diagnosis
From a Cummins/Onan service manual covering: 02SX1N1A, 04SX1N, 04SX1N1A, 04SX1N1B, 04SX1N2B, 04SX1N3B, 04SX1N4B, 06SX1N, 06SX1N1A, 06SX1N1B, 06SX1N2B, 06SX1N3B…. Check it applies to your exact model before use.
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Procedure
- Remove lead from battery polarity reconnection block to ammeter at ammeter.
- Install DC voltmeter between lead and ground.
- At governed engine speed, average DC output should be 19 to 21 volts.
- If output defective, test for open circuit or grounding in leads and windings.
- If leads defective, replace them. If winding defective, replace stator.
Tools required
- DC voltmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 19 to 21 volts DC average at governed speed
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.