Roomba charging error: which of the three parts failed

Three parts, and the number tells you which

iRobot frames the whole chart around one sentence worth reading before any of the codes: charging requires the battery, the robot and the dock all to be working properly. The robot is designed to detect temporary and permanent faults in any of those three and halt charging to keep things safe.

That is what makes the numbers useful rather than alarming. iRobot says the codes let you zero in on which part of the system is not working, and if user servicing does not fix it, they let a care agent take the right action. So the first job is not to fix anything — it is to read which of the three the number is pointing at.

Unusually for Roomba, this chart covers every model: the 500 to 900 series, e, i, j and s series, the 100/1000, 200/2000, Plus 400, Plus 500, Max 700 and m series. That is a relief after the cleaning-error charts, where the same number means different things on different generations.

The battery codes

Charging Error 1 — and its newer-app equivalent 101 — means the robot does not detect a battery at all, and iRobot’s action is to remove and reinstall it. That is worth doing properly rather than pressing on the outside: a battery slightly out of position reads as absent.

Errors 8, 9, 11, 17 and 20 are all battery faults with different characters. 8 means the robot cannot communicate with the battery. 9 and 11 are battery failures where iRobot says it may need replacing. 17 is an authentication failure. 20 is a battery fault or a battery not ready to charge, and it is the one with a distinctive remedy: remove the battery for fifteen minutes, then reinstall.

Errors 2, 3, 102 and 103 are charge faults, where iRobot asks you to confirm the battery is an authentic iRobot lithium-ion cell and to check for liquid damage. Liquid damage is the one cause on this page that no amount of reseating will help with.

The contact and temperature codes

Errors 4 and 5 are a low or absent current fault with the dock or the robot, and iRobot’s action is short: clean the charging contacts. Error 21 says the same thing from a different angle — the robot docked but was unable to charge — with the same remedy, and error 19 adds a charge timeout where the fix is to remove and reinstall the battery and clean the contacts.

That makes contact cleaning the single most useful physical act on this page, covering four separate codes. The contacts are metal strips on the underside of the robot and matching ones on the dock, and they collect the dust the robot spends its life gathering.

Errors 6 and 7 are neither the battery nor the dock: the battery is simply too warm or too cold to charge, and iRobot asks you to bring the robot to room temperature and try again. A robot docked in a conservatory, a garage or beside a radiator will produce these without anything being wrong, and the fix is to move the dock.

What iRobot says about third-party batteries

The chart carries a warning in its own words, and it is directly relevant to several of the codes: use only genuine iRobot batteries, be wary of unauthorised resellers and counterfeit products, and note that aftermarket batteries may result in these charging errors and will void the warranty.

That is the manufacturer’s position rather than ours, and it is worth reading as what it is. But the practical point stands regardless of how you feel about it: errors 8 and 17 are explicitly communication and authentication checks against the battery, so a replacement cell that does not answer correctly will produce them whether or not it holds charge perfectly well.

If a charging error appeared shortly after fitting a replacement battery, that sequence is the most likely explanation, and it is worth establishing before cleaning anything.

Sources and review notes

Checked on September 23, 2026. Based on iRobot’s charging error chart for all Roomba and Braava models, which is where the code meanings, the three-part framing and the actions come from. iRobot’s statement about aftermarket batteries is quoted as its position, not endorsed. Unlike the cleaning-error charts, this one covers every model, so the numbers here do not shift between series. iRobot’s support pages render only in a browser and cannot be checked by automated fetching. Glitchary is independent of iRobot.

• iRobot: charging error chart, all Roomba and Braava models