Perform comprehensive battery system testing on the 2023 Rivian EDV 500 electric vehicle to evaluate high-voltage battery health, capacity, cell balance, and overall system integrity.

Warnings

Tools required

Parts

• High-voltage safety lockout tags × 2 — Use OEM specification

Preparation

1. Ensure vehicle is parked on level ground in a well-ventilated service bay with adequate clearance
2. Verify fire suppression equipment rated for lithium-ion battery fires is readily accessible
3. Confirm all high-voltage safety equipment is present and in good condition
4. Don high-voltage insulated gloves and safety equipment before beginning any work
5. Place wheel chocks at all four wheels to prevent vehicle movement
6. Ensure vehicle has been stationary for at least 30 minutes to allow battery temperatures to stabilize
7. Connect Rivian diagnostic scan tool to vehicle OBD-II port
8. Review any stored diagnostic trouble codes related to battery system
9. Document current battery state of charge, mileage, and any customer concerns

Procedure

1. 1

   Access battery system information
   Using the Rivian diagnostic tool, navigate to the Battery Management System (BMS) module. Record the current battery state of charge (SOC), state of health (SOH), total pack voltage, and any active or pending fault codes. Document the number of charge cycles and battery age data. Review battery thermal management system status and coolant temperature readings.
2. 2

   Perform initial visual inspection
   Inspect the underside battery pack enclosure for any signs of physical damage, impact, corrosion, or coolant leakage. Check all high-voltage cable connections visible from exterior for proper seating, damage to orange cable sheathing, or corrosion at connectors. Inspect battery pack mounting points and verify pack is properly secured to chassis. If thermal imaging camera is available, scan battery pack exterior for unusual temperature variations.
3. 3

   Disable high-voltage system
   Using the diagnostic tool, command the vehicle into service mode to disable the high-voltage system. Remove the 12V auxiliary battery negative terminal to ensure complete system shutdown. Wait minimum 5 minutes for high-voltage capacitors to discharge. Locate and remove the manual service disconnect (MSD) plug from the high-voltage battery pack per Rivian service manual location. Install lockout tag on MSD plug to prevent reinstallation during testing.
4. 4

   Verify system de-energization
   Using the CAT III/IV voltage tester, verify zero voltage at the high-voltage busbar connections after MSD removal. Test at multiple high-voltage junction points to confirm complete de-energization. Use digital multimeter to double-verify zero voltage across main battery pack terminals. Document all voltage readings. Do not proceed unless all readings confirm system is fully de-energized.
5. 5

   Perform cell voltage analysis
   Using the diagnostic tool, access individual cell group voltage data from the BMS. Record voltage for all cell groups (typically 108-120 cells depending on configuration). Calculate the voltage delta between highest and lowest cell groups. Normal variance should be less than 50mV. Any cell group voltage deviating more than 100mV from pack average indicates potential cell degradation or balance issue. Document all cell voltages for comparison against Rivian specifications.
6. 6

   Check battery internal resistance
   Using the diagnostic tool's battery testing function, initiate an internal resistance test for each cell group. The BMS will apply small test loads and measure voltage response to calculate resistance. Record all internal resistance values. Elevated internal resistance (typically >5 milliohms for EDV pack cells) indicates aging or degradation. Compare values against Rivian service specifications and identify any outlier cells.
7. 7

   Evaluate thermal management system
   Review battery coolant temperature sensor readings across all zones of the pack. Verify coolant level in the EV Battery/Motor Coolant reservoir is at proper level. Check coolant pump operation by commanding pump activation through diagnostic tool. Verify coolant flow and listen for unusual pump noises. Inspect coolant hoses and connections at battery pack for leaks or damage. Temperature uniformity across pack zones should be within 5°C under stable conditions.
8. 8

   Perform isolation resistance test
   Using the diagnostic tool, access the isolation resistance monitoring system data. The BMS continuously monitors resistance between high-voltage system and vehicle chassis ground. Review current isolation resistance values - should be above 500 ohms per volt (minimum 200kOhm for 400V system). Any reading below specification indicates potential insulation breakdown, moisture intrusion, or ground fault. Document all isolation resistance values.
9. 9

   Conduct capacity test setup
   Reconnect the manual service disconnect plug and restore 12V auxiliary battery connection. Using diagnostic tool, command vehicle out of service mode. Ensure battery state of charge is between 90-100% for accurate capacity testing. If not, connect vehicle to Level 2 or DC fast charger and charge to appropriate level. Verify battery pack temperature is within 20-30°C range for optimal testing conditions.
10. 10

    Execute capacity discharge test
    Using the battery load tester or Rivian diagnostic software capacity test function, initiate a controlled discharge test. The system will discharge the battery at a specified C-rate (typically 0.5C to 1C) while monitoring voltage, current, and capacity. Monitor cell balance throughout discharge. Test should be performed until state of charge reaches 10-20% or per Rivian specifications. Record total energy capacity (kWh) delivered during test.
11. 11

    Analyze capacity test results
    Compare measured capacity against rated pack capacity (EDV 500 typically uses 135-160kWh pack depending on configuration). Calculate state of health percentage: (Measured Capacity / Rated Capacity) × 100. SOH above 90% is considered good, 80-90% is acceptable with monitoring, below 80% may require pack service. Review voltage curve during discharge for any irregular drops indicating weak cell groups. Document complete test results.
12. 12

    Perform recharge and balance cycle
    Connect vehicle to appropriate charging equipment and fully recharge battery pack to 100% SOC. During charging, use diagnostic tool to monitor cell balancing activity. The BMS should actively balance cells during top-end charging. Verify all cell groups reach target voltage within specification (typically within 10-20mV at full charge). Record final balanced cell voltages and any cells that required significant balancing current.
13. 13

    Review and document findings
    Compile all test data including cell voltages, internal resistance values, capacity measurements, thermal management performance, and isolation resistance readings. Compare all values against Rivian factory specifications and service thresholds. Generate diagnostic report through Rivian service software documenting battery health status. If any parameters fall outside acceptable ranges, note recommendations for monitoring frequency, pack service, or replacement per Rivian service guidelines.

Reassembly

1. No disassembly was performed during this diagnostic procedure
2. Ensure all high-voltage safety equipment has been properly removed from vehicle
3. Verify manual service disconnect is properly reinstalled if it was removed for testing
4. Confirm all diagnostic equipment is disconnected from vehicle
5. Remove all lockout tags and safety barriers

Verification

• Verify no diagnostic trouble codes are present in the BMS after testing completion
• Confirm battery state of charge displays correctly on instrument cluster
• Test drive vehicle to verify normal propulsion system operation and power delivery
• Monitor battery temperature during initial drive cycle to ensure thermal management system operates normally
• Verify regenerative braking functions properly indicating battery can accept charge
• Confirm all battery system warning lights are extinguished on instrument cluster
• Review test report data to ensure all measured parameters fall within Rivian specifications
• Document battery health status and provide customer with findings and any recommended follow-up actions

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