Battery appears to charge but runtime is very short (only a few minutes).

Safety first: Only use the original Grundig charger; do not attempt to open the battery pack.

• 1. Full charge cycle: Charge the vacuum until the indicator shows full, then leave it on the charger for an additional hour to ensure cell balancing.
• 2. Test runtime: Run the vacuum on normal mode from full charge until it stops. Compare the runtime to the specification in your manual.
• 3. Reduce turbo use: If runtime is acceptable on normal but very short on turbo, this may be normal behavior. Use turbo only when needed.
• 4. Replace battery: If runtime is significantly below spec on normal mode, replace the battery pack with a genuine Grundig Li-Ion battery designed for your model.