The charger LED flashes an error pattern, and the battery will not charge.

Safety: Unplug the charger from the mains before inspecting contacts.

• Inspect charger contacts: Look for bent, corroded, or recessed pins. Clean gently with a dry cloth.
• Check mains outlet: Plug another device into the same outlet to confirm power is present.
• Test another battery/charger: If possible, try charging a different Nilfisk battery on the same charger. If that works, the original battery is faulty. If no battery charges, the charger is likely defective.
• Allow battery to warm/cool: If the battery is very cold or hot, let it reach room temperature and try again.
• Do not use non-OEM chargers: Only use the specified Nilfisk charger to avoid further damage. Replace the faulty component as needed.