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SmartSense Gen. 2 Battery Firmware Update

Updated

SmartSense Gen 1 vs Gen 2.jpg

This article applies to SmartSense Gen. 2 (2025+) only, and covers how to update the firmware on the battery.

A critical update is required for the SmartSense Gen. 2 (2025+) battery that improves long-term battery health, increases battery life accuracy, and adds the ability to factory reset the battery with a 10 second button hold. If your battery firmware is not 2.24 or later, please perform the update. 

Check your firmware version

To verify the firmware version of your battery, open the Cannondale App and go to Garage. (Add your bike if it’s not there yet.) Tap into your bike’s SmartSense settings screen, then scroll to the bottom—the current Battery Firmware version is listed there:

BatteryFirmwareCheck.png

Battery Firmware less than 2.24 needs to be updated. Follow the steps below.

How to update Battery firmware using a computer or smartphone

This process will take up to 15 minutes to complete. It can be completed from your mobile phone or desktop computer. 

If you feel uncomfortable with any of these steps, please take the bike to your local dealer who will be able to help you with the process.

  1. First, make sure your eRTL615/616 Radar Taillight is on firmware 7.33 or above. See: SmartSense Gen. 2 Radar/Taillight Firmware Update
    If Radar/Taillight firmware is less than 7.33, the steps below will not work.
    Then proceed...
  2. Make sure that your battery is charged to at least 50%
  3. Remove your battery from the bike
  4. Download the latest Battery firmware here: https://app.cannondale.com/firmware/ssv2/battery/latest/EXTERN_1.img
    Note: Do not double-click or try to open the .img file on your computer or phone - doing so will usually result in a "corrupt" error message. You can ignore such a message. The .img file is only meant to be run by the SmartSense itself. Instead, simply download or save the file in order to copy it to your SmartSense in the steps below.
  5. Find the downloaded firmware file “EXTERN_1.img” in your computer or phone’s Downloads folderimage.png
  6. Connect your computer or mobile phone to the USB-C port (protected by a dust cover) on the back of your radar/taillight. A green LED will appear on the side of the radar/taillight when connected.
  7. Open a file window to find the “GARMIN” device in:
    1. Windows Explorer (PC)
    2. Finder (Mac)
    3. Files app > Browse tab (iOS)
    4. Files app > All Storage section (Android)
  8. Copy “EXTERN_1.img” from your Downloads into the folder named “EXTERNAL” here: GARMIN > REMOTESW > EXTERNAL
  9. Wait until the file has transferred to the radar/taillight. This may take a couple minutes. Make sure the copied filename is exactly “EXTERN_1.img” with no additional characters.
  10. Safely eject the radar device on PC/Mac. This is an option if you click on the USB icon in the bottom right corner of your home window in Windows OS, or click the Eject icon next to the device in Mac OS. (iOS and Android skip this step)
  11. Disconnect the USB-C cable from the taillight
  12. Wait 10 seconds
  13. Install the battery into the bike
  14. The bike should turn on for a few seconds, then enter firmware update mode.  This will be flashing blue/green on the status LED of the radar and flashing red/blue/green on the battery
  15. Wait until the status lights have stopped flashing and the system turns on.  This will take 10-15 minutes
  16. Once the system has turned on, check your SmartSense in the Cannondale App to make sure the battery firmware has updated to 2.24 or later.

Troubleshooting

If you have tried the battery firmware update once and did not succeed, then:

  • Make sure you first checked and updated the radar/taillight firmware as described in Step 1. If the radar/taillight firmware is less than 7.33, it will not be able to apply the battery firmware update.
  • Try again using a different device method. For example, if you tried desktop computer the first time, then try again with iOS or Android.
  • Make sure the firmware update file “EXTERN_1.img” has no additional characters in its filename and was copied completely to the Garmin > RemoteSW > External folder (rather than a shortcut link).
  • If the GARMIN device does not appear on your computer or smart phone, your cable likely does not support data transfer.  Please try again with a cable that supports data transfer.
  • Disc image file "corrupt" error message? Do not try to double-click on or launch the “EXTERN_1.img” file on your computer or phone. Instead, simply copy/paste the file as instructed in steps 5-9 above.

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