Generac Quietpact 40G (Gasoline) / 40LP (LP Vapor) Repair & Troubleshooting Guide

**TEST 15: CHECK BATTERY CHARGE OUTPUT**

**Discussion:**
The Battery Charge system includes a center-tap Battery Charge Winding, a Battery Charge Rectifier, and a Battery Charge Resistor. Normal output varies between 1 to 2 amps depending on generator load. Wire No. 66 is tapped at the rectifier and connected to the Engine Control Circuit Board at Pin J1-10 for the starter lockout signal. (Page 43)

**Procedure:**
1. Disconnect Wire No. 15 (fused battery supply) from the center terminal of the Battery Charge Rectifier.
2. Set VOM to measure DC Amps. Connect the positive (+) test lead to the center terminal of the Battery Charge Rectifier and the negative (-) test lead to the disconnected Wire No. 15.
3. Start the generator. The amp reading should be approximately 0.8 Amps.
4. Apply full load to the generator. The amp reading should increase to approximately 2 Amps. (Page 43)

**Results:**
* **IF GOOD:** If amperage is between 0.8 to 2 Amps, the charging system is functional. (Page 43)
* **IF BAD:** If no amperage is measured, verify VOM fuses and meter function. Ensure generator fuse F1 is not blown. If the meter and fuse are good, proceed to **TEST 16**. (Page 43)

---

**TEST 16: CHECK BATTERY CHARGE RECTIFIER**

**Discussion:**
The Battery Charge Rectifier (BCR) is a full-wave rectifier. (Page 43)

**Procedure:**
1. Disconnect Wire No. 66, Wire No. 15, and Wire No. 77 from the BCR.
2. Set VOM to Diode Test range. Connect negative (-) lead to the center terminal and positive (+) lead to an outer terminal; it should measure approximately 0.5 volts. Repeat for the other outer terminal (should also be approximately 0.5 volts).
3. Connect positive (+) lead to the center terminal and negative (-) lead to each outer terminal; both should measure "Infinity."
4. **Short to Ground Test:** Set VOM to resistance. Connect positive (+) lead to the BCR case housing. Connect negative (-) lead to each terminal (both outer and center) one at a time. All three must measure "Infinity." (Page 43)

**Results:**
* **IF BAD:** If any step fails, replace the Battery Charge Rectifier. (Page 43)
* **IF GOOD:** If the BCR tests good, proceed to **TEST 17**. (Page 43)

---

**TEST 17: CHECK BATTERY CHARGE WINDING / BATTERY CHARGE RESISTOR**

**Discussion:**
The Battery Charge Winding (BCW) delivers AC voltage to the rectifier and consists of Stator Leads Wire No. 66, Wire No. 77, and Wire No. 55. The Battery Charge Resistor limits current. (Page 43)

**Procedure:**
1. Disconnect Stator Leads Wire No. 66 and Wire No. 77 from the BCR. (Ensure Wire No. 66 "Black" is disconnected from Wire No. 66 "Blue"). Disconnect Wire No. 55 from the Battery Charge Resistor.
2. Set VOM to "R x 1" scale. Measure resistance between Wire No. 66 and Wire No. 55. Procedure specifies 0.140 - 0.174Ω. (Page 43)
3. Measure resistance between Wire No. 77 and Wire No. 55. Procedure specifies 0.140 - 0.174Ω. (Page 43)
4. Measure resistance between Wire No. 55 and Wire No. 11 & 33 (at CB1). Measurement must be "Infinity." (Page 43)
5. Disconnect Stator Lead Wire No. 2 from CB3. Measure resistance between Wire No. 55 and Wire No. 2. Measurement must be "Infinity." (Page 43)
6. Measure resistance between Wire No. 55 and frame ground. Measurement must be "Infinity." (Page 43)
7. Measure resistance between the Battery Charge Resistor terminal (where Wire No. 55 was) and frame ground. Measurement must be 1 ohm. If not, check Wire No. 0 for continuity to ground. (Page 43)

**Results:**
* **IF BAD (Steps 2-6):** Replace the Stator. (Page 43)
* **IF BAD (Step 7):** If Wire No. 0 has continuity but the resistor is not 1 ohm, replace the Battery Charge Resistor. (Page 43)
* **IF GOOD:** If all steps pass, perform the **Insulation Resistance Test**. (Page 43)

---

**INSULATION RESISTANCE TEST**

**Procedure:**
Perform the test as outlined in the general service instructions. (Page 11)

**Results:**
* **IF BAD:** Repair or replace relevant components as indicated by test findings. (Page 27)

**Summary Recommendation:**
Systematically verify the 0.8 to 2 Amps output before isolating the failure to the Battery Charge Rectifier, the 1 ohm Resistor, or the 0.140 - 0.174Ω Stator windings.