Aventon Mid-Drive Bikes – E29 Over Voltage Protection TroubleshootingUpdated 2 days ago
This article explains how to troubleshoot the E29 “Over Voltage Protection” error on Aventon mid-drive bikes.
Use this article if your bike:
- Shows error code E29
- Displays “Over Voltage Protection”
- Does not power or operate properly
- Experiences battery voltage issues
- Shuts down unexpectedly during operation
If you are unsure about any step or notice anything unsafe, stop troubleshooting and contact support.
Before You Start
Please prepare the following:
- order number
- Aventon model
- photo or video of the issue
- photo of the E29 error code
- when the issue first appeared
- whether the bike powers on
- whether the battery charges
- whether the display turns on
- whether the motor engages
- whether the issue happened after charging, riding, transport, storage, water exposure, crash, impact, modification, or third-party repair
- photos of any visible damage
Safety Warnings
- Do not continue riding if the bike has visible damage, overheating, smoke, burning smell, water exposure, or a persistent error code.
- Do not open sealed electrical components.
- Do not work on wiring while the bike is powered on or charging.
- Only use the correct Aventon battery designed for your specific bike model.
- Stop and contact support if you are unsure.
What This Error Means
E29 indicates the battery voltage is too high for the system to operate properly.
In some cases, the issue may be caused by:
- a high battery voltage condition
- the wrong battery being used
- a damaged battery
- a damaged mid-drive unit
Possible Causes
- battery voltage is too high
- incorrect battery installed
- damaged battery
- damaged mid-drive unit
Troubleshooting Steps
Step 1 – Verify the Correct Aventon Battery Is Installed
Check whether the bike is using the correct Aventon battery for that specific bike model.
Non-Aventon batteries or incorrect battery models may trigger the E29 error.
If yes
Fully charge the battery.
After charging is complete, restart the bike and check whether the E29 code remains.
If no
Replace the battery with the correct Aventon battery for the bike model.
After replacing the battery, restart the bike and check whether the E29 code remains.
If the issue clears
The issue was likely caused by using the incorrect battery.
If the issue remains
Check the voltage of the fully charged battery.
Step 2 – Check Battery Voltage
Check the voltage of the fully charged battery.
Refer to the Battery Voltage Guide for the correct battery voltage measurement procedure.
Expected fully charged voltage ranges:
- 36V battery: approximately 42V when fully charged
- 48V battery: approximately 54V when fully charged
If yes
If the battery voltage is within the normal range and the E29 code remains, replace the mid-drive unit.
If no
Replace the battery.
After replacing the battery, restart the bike and check whether the E29 code remains.
If the issue clears
The issue was likely caused by a damaged or incorrect battery voltage condition.
If the issue remains
Replace the mid-drive unit.
Step 3 – Replace the Mid-Drive Unit
If the battery voltage is normal and the E29 code still remains, the mid-drive unit may be damaged.
Replace the mid-drive unit.
If the issue clears
The issue was likely caused by a faulty mid-drive unit.
If the issue remains
Please contact support for further diagnosis.
When To Contact Support
Please contact support if:
- the E29 error remains after completing the steps above
- there is visible damage
- the battery does not charge
- the bike does not power on
- the display does not power on
- the motor does not engage
- the issue appears related to the battery, battery terminals, charger, mid-drive unit, or internal wiring
- the bike has been exposed to water, crash, impact, transport damage, modification, or third-party repair
- you are unsure how to safely complete a step
- you need warranty, repair, replacement part, refund, or replacement support
If the issue remains after this step, please contact our support team and include the photos/videos listed below.
What To Send Support
Please send:
- order number
- Aventon model
- photo or video of the E29 error code
- photo of the display
- photo of the battery area
- photo of the charger and charger light
- battery voltage reading, if available
- photos of visible damage
- confirmation of whether the bike powers on
- confirmation of whether the battery charges
- confirmation of whether the display turns on
- confirmation of whether the motor engages
- confirmation of whether there was water exposure, crash, impact, modification, or third-party repair
- list of troubleshooting steps already completed
Important Safety Notes
- Do not continue riding if the E29 error remains.
- Do not ride if there is visible damage, overheating, smoke, burning smell, water exposure, or motor resistance.
- Do not use non-Aventon batteries.
- Do not open the battery, controller, mid-drive unit, or sealed electrical components.
- Do not force connectors.
- Do not work on wiring while the bike is powered on or connected to the charger.
- Contact support if you are unsure.