Display shows F2 during charging; battery icon does not increase.

Safety first: Do not attempt to heat the battery with external heat sources or cool it in a freezer.

• Normalize temperature: Bring the vacuum and charger indoors to a room-temperature environment (15–30°C / 59–86°F). Let them sit for at least 1 hour.
• Retry charging: After the battery reaches room temperature, place it back on the charger and check if F2 clears.
• Check placement: Ensure the charger is not near radiators, windows with direct sun, or unheated areas.
• Replace battery if persistent: If F2 appears even at normal room temperature, the internal temperature sensor in the battery pack may be defective. Replace the battery with a genuine Sencor pack.