Roomba not charging: safe checks before replacing a part

A Roomba that does not charge is a system problem until the evidence identifies one component. iRobot explains that charging depends on the battery, robot and dock working together, and its error chart separates contact faults, temperature conditions, communication errors and battery failures. Do not begin by ordering a battery. First note the spoken message, red-light sequence and notification in the iRobot app, because the complete code determines which part of the system deserves attention.

Start with the power path and the physical meeting point between robot and dock. Make sure the dock cable is fully seated and the wall outlet is supplying power, then unplug the dock for 60 seconds before cleaning. Place the robot upside down on a flat surface. iRobot accepts only a lightly dampened cloth or lightly dampened melamine foam on the charging contacts; abrasive materials can damage the finish that carries current. Clean the robot pads and the matching dock pads until their surface has a visible shine, then allow them to be dry before reconnecting power.

The condition of the contacts changes the conclusion. Ordinary grey dirt or residue may be removable. Contacts that have turned green or copper-coloured are considered damaged by iRobot and require replacement of the robot or base that carries them, not harder scrubbing. Inspect the contact movement where the dock design exposes it, but do not lever or dismantle the assembly. Clean the docking sensor window separately with a dry microfiber or soft cotton cloth. Melamine foam belongs on the contacts, not on that sensor, and no water or cleaning spray should enter a sensor opening.

Use the reported charging error to avoid guesswork. Errors 4 and 5, and the corresponding 104 and 105 family, point to no or low current and lead back to the contacts. Errors 6 and 7, or 106 and 107, indicate that the battery is too warm or too cold, so the robot should return to room temperature before another attempt.

Communication and battery-detection codes require the exact app route and, where the model permits, correct battery seating. Battery-failure or authenticity codes are different again. iRobot warns that unauthorised aftermarket batteries can cause charging errors and affect warranty coverage.

After the dock reset and approved cleaning, place the robot squarely on the dock and make one controlled charging observation. A normal charging indication without the previous code shows that power delivery or contact contamination was involved. If the same code returns, preserve it rather than repeatedly lifting and replacing the robot. Temperature codes need time in a normal indoor environment; damaged contacts, liquid evidence, a battery communication fault or a persistent failure needs iRobot support.

Never spray the dock, use a metal abrasive, open a battery pack or bypass the charging system. Stop for burnt marks, stuck contacts, heat, swelling, liquid or an electrical smell. The safest replacement decision comes after matching the exact model, code and failed component—not from the broad symptom “Roomba does not charge.”