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Autopapyrus · XPeng G3 47 kWh Single Motor (2020)
https://autopapyrus.com/guides/xpeng/g3/high-voltage-battery-inspection/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

XPeng G3 47 kWh Single Motor (2020): High-Voltage Battery Inspection

Inspecting the XPeng G3 high-voltage battery includes BMS (Battery Management System) diagnostics, a battery state of health (SOH) check, module and cell voltage checks, temperature monitoring, and an insulation test of the high-voltage circuit. Working on the HV system requires strict adherence to safety procedures and specialized equipment.

Difficulty: Hard Time: 2-3 hours (specialized equipment required) Steps: 13 Tools: diagnostic scan tool with XPeng BMS support, insulation resistance tester (megohmmeter, 500-1000 V test voltage), CAT III 1000V multimeter, Class 00 or Class 0 (1000 V) dielectric gloves, safety glasses, insulated tools

Part

  • 🔩 The inspection does not require replacing any parts. If faults are found, contact an authorized XPeng service center

Step by step

13 steps
  1. Preparation and safety — Park the vehicle on a level surface, apply the parking brake, and shift the selector to P. Put on Class 00 dielectric gloves (500 V minimum) or Class 0 gloves (1000 V) and safety glasses.
  2. Disconnecting the high-voltage system — Turn the ignition off and remove the key. Open the hood and locate the HV service disconnect plug. It is usually on the high-voltage battery under the floor or in the motor compartment (check the XPeng G3 documentation for the exact location). Disconnect it following the manufacturer's instructions.
  3. Waiting for capacitor discharge — After disconnecting the service disconnect, wait at least 5-10 minutes for the high-voltage capacitors in the inverter and control system to discharge. Discharge time can vary, so follow the XPeng procedure (usually 5-15 minutes).
  4. Verifying that no high voltage is present — Using the CAT III 1000V multimeter, measure the voltage between the positive and negative HV battery busbars and between each busbar and the vehicle body ground. Readings should be close to zero (less than 10 V). Continue only after you have confirmed there is no voltage.
  5. Visual inspection of the battery — Inspect the battery case for damage, deformation, signs of electrolyte leakage, corroded connectors, and damaged high-voltage (orange) cables. Check the wire insulation for integrity, and look for melting or cracks in the case. The XPeng G3 uses an IP68-rated battery with an aluminum case. Any dents or loss of sealing are critical.
  6. Connecting the diagnostic scan tool — Connect an OBD-II scan tool with XPeng BMS protocol support to the diagnostic connector (located under the steering column on the left). Turn the ignition on (without starting the HV system). Enter the battery diagnostics menu.
  7. Reading diagnostic trouble codes (DTCs) — Run a full scan of the battery management system. Record all fault codes related to the battery, BMS, temperature sensors, and voltage sensors. Typical codes may indicate cell imbalance, overtemperature, or loss of isolation.
  8. Checking battery state of health (SOH) — In the BMS diagnostics menu, find the SOH (State of Health) parameter. For a 2020 XPeng G3 battery, a normal SOH is 90-100% (a new battery may show 98-100%). A value below 80% indicates significant battery degradation, and below 70% means replacement is required.
  9. Checking module and cell voltage — Check the voltage of all battery modules in real time. The 47 kWh battery consists of several modules, each containing many cells. The normal voltage of a single NCM811 cell is 3.0-4.2 V (nominal about 3.7 V). The voltage spread between cells should not exceed 0.03-0.05 V. A spread of more than 0.1 V indicates imbalance or a faulty cell.
  10. Checking temperature — Check the battery module temperatures through the BMS. Normal operating temperature is 20-35°C, with an allowable range of 10-45°C. The temperature spread between modules should not exceed 5°C. A temperature above 50°C or uneven heating indicates a problem with the cooling system or a faulty cell.
  11. High-voltage circuit insulation test (if you have a megohmmeter) — Connect the megohmmeter between the positive HV battery busbar and vehicle body ground, then between the negative busbar and ground. Set the test voltage to 500 V (for 300-400 V systems). Insulation resistance must be at least 100 MΩ/V (for a 360 V battery, at least 36 GΩ, ideally more than 100 GΩ). A value below the threshold indicates a loss of isolation (LOI), which is a critical fault that requires immediate repair.
  12. Analyzing the diagnostic results — If SOH is above 85%, the cell voltage spread is less than 0.05 V, temperatures are normal, insulation is above 100 MΩ/V, and there are no DTCs, the battery is in good condition. If there are any deviations, record the data to give to the XPeng service center.
  13. Restoring the system — Disconnect the diagnostic scan tool and reinstall the HV service disconnect following the instructions. Close the hood. Turn the ignition on and make sure there are no warnings on the instrument cluster. Take a test drive to confirm the system works normally.

Common mistakes and warnings

  • The XPeng G3 high-voltage battery operates at about 350-400 V, which can be fatal if safety procedures are not followed. You MUST use Class 0 or higher (1000 V) dielectric gloves, insulated tools, and safety glasses. NEVER work on the HV system without disconnecting the service disconnect and waiting for the discharge time. If you find damage to the battery case, a leak, a burning smell, BMS fault codes, or low insulation (below 100 MΩ/V), STOP work IMMEDIATELY and contact an authorized XPeng service center. Repairing the high-voltage battery yourself is strictly prohibited. Only perform diagnostics. Repair and replacement of battery modules must be done only by certified technicians with equipment for working on HV systems. If electrolyte gets on your skin, rinse thoroughly with water and see a doctor. Lithium-ion batteries are a fire hazard. If one catches fire, use a Class D fire extinguisher or a large amount of water (at least 500 L (132 gal)).