Roomba Charging Error 4: Why Isn't It Charging and How Do I Fix It?

Problem Description

Roomba announced Charging Error 4, meaning electrical current isn't reaching the robot. iRobot narrows it to four culprits - the robot's contacts, the battery, the Home Base, or the power cord - but dirty charging contacts cause the vast majority of cases.

Why This Happens in Real Homes

Charging Error 4 is Roomba reporting that no charging current is reaching the robot. iRobot narrows it to four things - the robot's contacts, the battery, the Home Base, or the power cord - but in practice the overwhelming cause is dirty or oxidized charging contacts on the robot's underside and the dock's ramp. A thin film of dust is enough to break the low-voltage charging connection.

Clean both sets of contacts first, then work outward: reseat the power cord at the base and wall, confirm the outlet isn't on a switch or a tripped GFCI, and make sure the robot docks squarely so its contacts meet the dock's. If cleaning and reseating don't restore charging, swap-test the outlet, dock, and battery to find the failed part before contacting iRobot.

Symptoms

• Roomba announces Charging Error 4
• Robot won't charge on the Home Base
• Charging light doesn't come on when docked
• Battery stays low or dead despite docking
• Robot docks but doesn't power up
• Home Base light is off or not lit
• Robot charges only intermittently
• Error 4 continues after a quick contact wipe

Recognize these? Here's what usually causes it.

Common Causes

• Dirty or oxidized charging contacts on the robot or dock
• Home Base not plugged in or on a switched outlet
• Power cord loose at the Home Base or the wall
• Robot's contacts not lined up with the dock's contacts
• Debris or a mat under the Home Base tilting it
• A large coil of excess cord causing a weak connection
• Failing Home Base or power supply
• Aging battery no longer accepting a charge

Tools & Requirements

Step-by-Step Solution

1

Understand the Error

Charging Error 4 means electrical current isn't reaching the robot. iRobot points to four possible culprits: the robot's charging contacts, the battery, the Home Base, or the power cord. The most common by far is dirty charging contacts, so start there.

2

Clean the Charging Contacts

Flip the robot over and find the two metallic charging contacts (coppery pads) on the underside front edge. Wipe them with a dry cloth or a melamine eraser. Do the same on the two matching contacts on the Home Base's charging ramp. Oxidation and a film of dust here block the low-voltage connection.

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3

Check the Power Cord

Confirm the power cord is firmly seated in the socket on the back of the Home Base and fully plugged into the wall. Push both ends in. A half-seated barrel plug at the dock is a classic Charging Error 4 cause.

4

Confirm a Live Outlet

Make sure the outlet isn't controlled by a wall switch or a tripped GFCI. Plug a lamp into the same outlet to confirm it has power, or move the dock to a known-good outlet that stays on.

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5

Line Up the Contacts

Set the robot on the dock and check that its underside contacts sit directly on the dock's contacts. If the robot parks crooked, reposition the dock against a wall on flat hard floor so the robot docks squarely every time.

6

Manage the Excess Cord

The Home Base has a cord-wrap channel on the back. Don't leave a large loose coil of cord behind the base - tuck the excess into the wrap channel so the plug can't slowly work its way loose.

7

Reseat the Battery

Remove the two screws on the yellow battery door on the underside, lift the battery out, and press it firmly back in. A loose battery can read as no current reaching the robot even when the dock is fine.

8

Isolate the Failed Part

If power still isn't reaching the robot, swap-test the parts: try another outlet, another compatible Home Base, or a new power supply. If a fresh battery and a known-good dock still throw Error 4, the robot's charging circuit may have failed - contact iRobot.

Quick Solutions

Still having issues? This is usually the deeper cause below.

Need More Help? iRobot Support

Note: The contact information below connects you directly to iRobot's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.

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