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Roomba Charging Error 19 or 21: docked but charge times out or never starts
Error 19 is a charge timeout; Error 21 means the robot docked but could not charge.
Start here
Error 19 is a charge timeout; Error 21 means the robot docked but could not charge. Start with contact condition and dock power, then reset/reseat the battery if the connection looks healthy.
Check these first
- Check dock power and cable seating.
- Clean and inspect contacts for wear/discoloration.
- Confirm the robot is sitting in the model-correct dock orientation and actually acknowledges placement.
Fix it in this order
- Clean contacts and align the robot correctly.
- For Error 19, try the iRobot sleep/ship-mode and battery-reseat procedure.
- If percentage still does not rise, isolate dock vs robot with a known-good compatible component when available.
- Service the damaged side of the power path.
Evidence to keep
- Before/after battery percentage
- Dock acknowledgement
- Contact photos
- Whether alignment changes charging
Do not make it harder
- Leaving the robot indefinitely on a connection that repeatedly times out
- Sanding contacts aggressively
- Replacing both dock and battery without isolating the failing side
How you know it is fixed
- Charging starts every time the robot docks and percentage increases at a normal rate.
If the obvious fix does not work
- If wiggling the robot makes charging start, stop treating it as software; contact geometry/wear is the likely clue.
- If the dock never acknowledges placement after cleaning and correct alignment, the dock is more suspect.
- If the dock acknowledges placement but charging times out, battery/robot charging hardware becomes more suspect.
If this still isn't resolved
- iRobot support with dock/contact/battery isolation results
Sources for this path
Use these references to confirm provider-, model-, policy-, or jurisdiction-specific details before an irreversible step.
Need the complete context?
This page solves one branch. The parent guide covers the full decision, edge cases, alternatives, and related checks.