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

Safety first: Power the vacuum OFF and remove the battery pack from the handle before any inspection. Do not short battery terminals.

• Fully recharge the battery: Place the ETA battery pack on the original ETA charging base or plug the wall charger into the vacuum (depending on model). Allow a full uninterrupted charge (typically 3–5 hours) until the LED on the charger or battery indicates full.
• Inspect battery contacts: With the battery removed, inspect the metal contacts on both the battery and the vacuum handle. If you see oxidation or dust, gently clean with a dry cloth or a cotton swab slightly dampened with isopropyl alcohol. Let dry completely before reinstalling.
• Check charger output: Plug the ETA charger into a known-good outlet. Confirm the charger LED turns on. If you have a multimeter and are qualified, verify the output voltage matches the rating on the charger label (usually around 26–30 V DC for ETA cordless vacuums). Replace the charger if there is no output.
• Cool down the battery: If the pack feels warm, let it cool at room temperature for 30 minutes and then try charging again. Overheated packs may trigger undervoltage/overcurrent protection.
• Test after charge: Reinstall the battery firmly until it clicks. Turn the vacuum ON. If E1 reappears immediately with a fully charged pack, the internal BMS or cells are likely faulty and the pack should be replaced.

When to call a technician: If the battery swells, leaks, or becomes very hot, stop using it immediately and contact ETA service or a qualified technician for safe disposal and replacement.