81 | Controller - Battery communication error

Troubleshoot battery communication errors.

Written by Alex Kovell

Last published at: September 9th, 2025

Description

System communication with the battery is interrupted. The connection between the battery and the controller may be damaged. The communication between various components ensures that the e-bike functions properly. When the system detects a communication interruption between the battery and the HMI lasting for more than 5 seconds, this error code will appear, affecting the e-bike's functionality.

⚠️Triggers of Error Code

The following are possible causes of error code 81:

  • Loose or damaged connection between the battery and controller
  • Faulty communication between the battery and HMI
  • Damaged wiring or connectors affecting communication

⚠️Warning

If Error 81 and Error 84 are both detected simultaneously, it is highly likely that the battery is not the issue. Please resolve Error 84 first before addressing Error 81.

1 E-bike remains stationary

Before proceeding with the e-bike inspection, ensure the bike is stationary, and do not sit on the bike, pedal, or apply any force to the pedals.

 
 

2 Turn off the e-bike and remove the Battery

Long press the power button to turn off the e-bike.If the battery is removable, detach it and inspect both the battery discharge terminal and the battery mounting base for any bent or broken pins. If yes, replace the damaged battery or mounting base. Otherwise, proceed to the next step.

 
 

3 Replace the Battery

Replace the [Battery] with a new spare, then reboot the e-bike to check if the error code still exists. If this doesn't fix the issue, proceed to the next step.

 
 

4 Check the Cable and Connector Pins

Check the cable between [Battery] and [Controller] for damage. Then, unplug the cable connector and examine the connector pins for bends or breakage. If any issues are found, replace the damaged component or extension cable. If both the cable and connector are in good condition, proceed to the next step.

 
 

5 Ensure the Connector is Connected Tightly

Check if the cable connector is plugged in properly. If the connection is loose, plug the connector back in tightly. When plugging the connectors, ensure the arrow symbols on the two connectors are aligned.

 
 

6 Replace the Controller

Replace the [Controller] with a new spare, then reboot the e-bike to check if the error code still exists. If this doesn't fix the issue, proceed to the next step.

 
 

7 Replace the HMI

Replace the [HMI] with a new spare, then reboot the e-bike to check if the error code still exists. If this doesn't fix the issue, proceed to the next step.

 
 

8 Reach out to the Service Team if you need additional support!

Contact Customer Care or the Hyena Service Center for further technical assistance.

 
 

 


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