Cordless vacuum will not power on, 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 full.
• 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 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.