Novoferm garage door opener with battery backup does not operate during a mains failure.

Safety first: Disconnect mains power and follow Novoferm instructions when handling batteries.

Steps to try:

• Check connections: Ensure the battery connector is firmly plugged into the control board or battery module.
• Inspect battery: Look for swelling, leakage, or corrosion. Replace the battery if any damage is present or if it is older than the recommended service life.
• Charge test: Restore mains power and allow the battery to charge for several hours, then test operation with mains disconnected.

If the battery is good but backup still fails, the charger or battery module may be defective.