When the robot will not charge or dock

This page has no product recommendations on it, because nothing on it is solved by buying something. That is deliberate. Work down the list.

1. The contacts

By far the most common cause and the least dramatic. The metal charging contacts on the robot's front or underside, and the matching pads on the dock, accumulate a thin film of dust and pressed-in grime. It is often invisible. The robot arrives at the dock, seats correctly, and reports a charging error or simply sits at the same percentage.

1. Power the robot off and unplug the dock.
2. Wipe both sets of contacts with a dry cloth. A pencil eraser works on stubborn oxidation.
3. Do not use water or solvent on the contacts.
4. Refit and try again before doing anything else.

2. The dock's position

If the robot cannot find the dock at all, rather than failing to charge once there, the dock is usually badly placed. Docks need clear space to either side and a clear run in front — manufacturers publish clearance figures in the manual and people rarely read them. A dock tucked into a corner or behind a chair leg is a dock the robot approaches at an angle it cannot correct.

• Give it clear space on both sides and a meter or so of clear floor in front.
• Put it on a hard floor rather than deep carpet, so the robot arrives level.
• Keep it away from direct sunlight, which can interfere with the infrared docking beacon.
• Do not move it after mapping. On most systems the dock is the map's origin, and moving it invalidates the map. If you must move it, remap afterwards — see mapping tips.

3. Power

Obvious and worth ruling out properly. Try the dock in a different outlet, check the plug is fully seated, and look for a status light on the dock. If the dock shows no light in a known-good socket, the fault is the dock or its supply rather than the robot — and docks are usually replaceable separately.

4. The battery

If the contacts are clean, the dock is well placed and powered, and the robot charges to a low percentage or drains almost immediately, the battery is the remaining candidate. Ageing is gradual — the signal is roughly half the original runtime on a full charge. What each maker publishes about runtime, and when a pack is genuinely finished, is on battery life compared.

If it charges but will not start

That is a different symptom. Usually a full bin, a brush jam triggering a protective cut-out, or a schedule conflict. The ten-minute maintenance pass covers the mechanical causes, and the schedule tab covers the rest — a robot that starts by itself and a robot that will not start are often the same forgotten automation.