Cordless vacuum will not power on; the display shows E1 shortly after pressing the power button.

Safety first: Turn the power switch off and remove the battery pack from the vacuum. Do not attempt to open the battery casing; lithium-ion packs can be dangerous if punctured or shorted.

• Step 1 – Check charge level: Place the Tower battery pack on the original Tower charger. Confirm the charger LED comes on. Allow it to charge for at least 3–4 hours or until the charger indicates a full charge.
• Step 2 – Inspect battery contacts: With the battery removed, visually inspect the metal contacts on both the battery and the vacuum handle. If you see dust or light corrosion, gently clean with a dry cloth or a cotton swab slightly dampened with isopropyl alcohol. Let it dry fully before refitting.
• Step 3 – Reseat the battery: Reinstall the battery pack firmly until it clicks. A loose fit can trigger undervoltage or intermittent connection errors.
• Step 4 – Test on low power mode: Turn the vacuum on in the lowest power setting first. If it runs briefly then shows E1 again, the pack may have lost capacity.
• Step 5 – Try another outlet/charger: If available, test with a known-good Tower charger compatible with your model to rule out a charger fault.
• When to replace: If E1 persists after a full charge and contact cleaning, the internal cells or BMS are likely failing. Replace the complete Tower lithium-ion battery pack with the exact model specified in your user manual. Do not mix third-party packs.