Roomba Error 18 — Charging Error

What Does This Error Mean?

Error 18 is a charging fault — the Roomba and the dock aren't making good contact, or the battery isn't accepting charge.
Most cases come down to dirty contacts on either the dock or the robot.
Wipe both with a dry cloth and try docking again.
If the error persists, check the dock power and then test the battery.

Affected Models

Roomba i7
Roomba j7
Roomba s9
Roomba 980
Roomba 692

Common Causes

Dirty charging contacts — dust or pet hair on the metal pads (most common)
Dock not properly powered — adapter unplugged or outlet dead
Battery aged out (over 3 years usually)
Charging circuit on the main board fault (uncommon)
Wrong dock-charging adapter being used

How to Fix It

Wipe the contacts on the robot.

Flip the Roomba and find the two metal pads on the bottom-front.
Wipe them with a dry cloth.
If they look dirty or oxidised, use a pencil eraser to clean them — that gets a clean metal surface back without scratching.
Wipe the contacts on the dock.

The dock has matching metal contacts where the robot lands.
Wipe those too with a dry cloth.
Check that the dock is fully plugged in at the wall — the indicator light should be solid.
Manually dock the robot.

Place the Roomba on the dock by hand, lining the contacts up carefully.
If charging starts (you'll hear a chime and the battery icon will animate), the contacts were the issue.
If charging doesn't start, the issue is in the battery or charging circuit.
Try a different outlet.

If the dock seems to have power but the robot won't charge, swap to a different wall outlet.
A weak or partially-failed outlet is an easy thing to miss.
Plug a phone charger into the original outlet to test.
Check battery age.

Roomba batteries last about 3 years of regular use.
If yours is older and Error 18 keeps appearing despite clean contacts and good outlet power, the battery is at end of life.
iRobot replacement batteries are $40–$80 and slot in with one screw.

Frequently Asked Questions

Can I use a third-party Roomba dock or charger?

Original iRobot docks are recommended.
Generic third-party chargers vary widely in quality, and an underspec'd one can produce Error 18 even with a healthy battery.
If you've recently swapped to a non-iRobot charger, switch back and see if the error clears.

Why doesn't my Roomba dock automatically when I press Home?

Several causes: dock placed in a tight space, the robot can't see the dock's IR beacon, or the home location wasn't saved.
None of those are Error 18 specifically — they're navigation issues.
If the robot finds the dock but can't charge, that's when Error 18 comes up.