Cordless SEBO vacuum will not accept charge; charger LED blinks error pattern and vacuum indicator shows five flashes when battery is inserted.

Safety first: Disconnect the charger from mains before handling contacts. Do not open the battery pack casing.

• Verify genuine SEBO battery: Check the label on the battery for SEBO branding and correct model number. Third-party or modified packs may not be recognized.
• Inspect contacts: Look at the metal contacts on the battery and inside the vacuum battery bay. Clean gently with a dry, lint-free cloth. Do not use liquids or abrasives.
• Check for bent pins: If any contact pins are bent or pushed in, do not force the battery. The battery bay or battery pack may need replacement.
• Test on charger only: Place the battery directly on the SEBO charger (if separate). If the charger also shows an error or refuses to charge, the battery's internal electronics are likely faulty.
• Try another battery: If available, test with a second SEBO battery. If the second battery works normally, replace the original battery pack.
• Service recommendation: If multiple batteries show E5 in the same vacuum, the main control PCB or battery connector board in the vacuum may be defective and should be replaced by a technician.