Roomba Charging Error 8 — Battery communication fault
DIRECT ANSWER
COMMON CAUSES · RANKED
Loose battery connection MOST COMMON
The data pins lose contact when the pack shifts even slightly in its bay.
Aftermarket battery without proper comms
Clone lithium packs frequently fail the data exchange iRobot chargers require.
Dirty contacts interrupting data
Grime on charging or battery contacts corrupts the link mid-charge.
Battery electronics failing UNCOMMON
A pack that keeps dropping comms after cleaning and reseating is dying.
HOW TO FIX IT
Power off and remove the battery before reseating it, and never use a pack with cracked or swollen casing.
Reseat the battery
Power off, remove the pack, wait ten seconds, and reinstall it firmly.
Confirm it's a genuine pack
Check for iRobot lithium-ion markings. If a clone battery is installed, that's your answer.
Clean contacts and wheels
With the dock unplugged, wipe the charging contacts on robot and dock; dirty wheels can also lift the robot off the contacts.
Replace the battery if it recurs
Repeated comms drops from a genuine, clean, well-seated pack mean the battery has failed.
COMPATIBLE PARTS
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Lithium-ion battery — e & i series
Unplug the robot and remove the bin before opening the battery door; dispose of old cells at a battery recycling point.
Check price on Amazon ↗Lithium-ion battery — s series
A healthy s9 battery runs well over an hour; sudden short runtimes usually mean the pack, not the charger.
Check price on Amazon ↗Verification
Last verified: 2026-07-05 · How we verify a fault code
Corrections
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