BMS Configuration Fix

If you’re encountering issues with your Onyx 41Ah battery, such as inaccurate charge readings or premature cut-offs, it’s crucial to verify and adjust the Battery Management System (BMS) settings. Follow these steps to address common misconfigurations.

Onyx 41AH - BMS Apps Download

Identify Your BMS Model

  • The original Onyx 41Ah battery is equipped with an 80A BMS, but newer versions may include the 100A model.
  • Misconfigured settings, such as incorrect “Charge” or “Discharge Overcurrent Protection” or an inaccurate “Total Cycle Capacity,” can significantly affect performance.

Prepare for Configuration

  • Changes can be made whether the battery is installed in the bike, removed, or connected to a charger.
  • Ensure you are within 5 feet of the battery while using the app.

Using the Xiaoxiang BMS iOS App

  • Download the App: Install the Xiaoxiang BMS app.
  • Connect to the Battery: Open the app, pair it with your Onyx 41Ah battery, and navigate to the Config tab.
  • Unlock Full Features: Purchase the Pro version of the app if necessary for advanced configurations.

Check and Update Settings

  • Load Current Settings:
  • Go to BMS Settings and tap BMS Read.
  • Verify Fields:
  • Total Battery Capacity: Ensure it’s set to 41000.
  • Total Cycle Capacity: Confirm it’s set to 32800. If incorrect, tap the field and update it to 32800.
  • Save Changes:
  • Tap BMS Write in the top-right corner to save the updates.

Confirm and Apply Changes

  • Verify Adjustments:
  • Tap BMS Read again to ensure the new values are applied.
  • Overcurrent Protection Settings:
  • Scroll down to verify the following:
  • 80A BMS:
  • Charge Over Current: 90000
  • Discharge Over Current: 90000
  • 100A BMS:
  • Charge Over Current: 110000
  • Discharge Over Current: 110000
  • Adjust if Necessary:
  • If values differ, update them and save changes with BMS Write.

Balancer Configuration

  • Start Voltage: 3700
  • Delta to Balance: 15
  • Balance Only When Charging: OFF (Grey)

Monitoring Cell Balance

  • Access Cell Data:
  • Open the Xiaoxiang BMS app and check the “Cells” reading, represented by a triangle below “Power” in the top-left corner.
  • Interpret Values:
  • A healthy cell balance for the Onyx RCR is 0.040 or lower.

Addressing High Balancer Readings

  • If the Value Exceeds 0.040:
  • Charge the battery fully.
  • Toggle “Balance Only When Charging” to OFF.
  • Allow 1–2 days for the cells to balance.
  • Target Reading:
  • Aim for a reading below 0.020.

Note: Poor charging habits can increase the delta above 0.060, potentially causing premature cut-offs during acceleration or at low battery levels.

By following these steps, you can ensure your Onyx 41Ah battery is properly configured for optimal performance and extended lifespan.