Cordless SEBO vacuum shows seven red flashes and does not start; often after long storage or deep discharge.

Safety first: Use only the official SEBO charger. Do not attempt to jump-start or open the battery pack.

• Check charger output: Plug the charger into a known-good outlet. Confirm the charger's indicator light behaves normally (steady or slow blink per SEBO manual). If no light, the charger may be faulty.
• Long charge attempt: Place the battery on the charger and leave it for several hours, even if the indicator initially shows an error. Some BMS circuits will slowly recover from deep discharge.
• Warm environment: Charge the battery at room temperature (15–25°C). Very cold or hot conditions can prevent charging and trigger undervoltage/temperature protection.
• Test in vacuum: After extended charging, insert the battery and attempt to power on. If E7 persists and runtime is extremely short, the battery cells are likely damaged.
• Replace battery: Do not continue using a battery that repeatedly triggers undervoltage errors; replace with a new SEBO battery pack.