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Roomba 521
Battery Error 3 Repair

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In this project, the dreaded “Battery Error 3” charging error was tackled on an old Roomba 521 vacuum robot.

 

This error can be found in older models of Roomba robots and is often referred to as the “Red Ring of Death” for robot vacuums.

In this project, the dreaded “Battery Error 3” charging error was tackled on an old Roomba 521 vacuum robot.

 

This error can be found in older models of Roomba robots and is often referred to as the “Red Ring of Death” for robot vacuums.

Symptoms

  • The vocal message “Charging Error 3” when attempting to charge the robot through the docking station or by direct connection.

  • A red ring appears when attempting to charge the device.

  • The battery does not recharge regardless of how long plugged in.

  • The battery re-learn feature cancels, reporting the error.


 

Quick Fix’s

There are many reasons why an error may occur when charging your robot, from a bad battery, or a loose connection, all the way to a bad motherboard. Below are some initial tips to attempt to remedy the issue.

 

  • Wipe clean the connections on the charging dock

  • Plug the charger directly into the robot

  • Clean the connections to the battery itself

  • Try another battery (if one is spare)

  • Try a battery reset (Hold down “Dock” and “Spot” buttons for 10-20 seconds and let go - the robot should make a tone) which will let the robot re-learn the battery's charging and running characteristics.

The Investigation
1 - Overview
 

To initiate the repair, we first need to strip down the robot to expose the error, as the basic checks show the fault lies within the robot. Below is a picture of the top face of the robot in question.

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More Coming Soon
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