Cordless vacuum will not power on, display shows E1 immediately or after a short beep

Safety first: Turn the power switch off, remove the battery pack from the vacuum, and disconnect the charger from the wall before inspecting anything.

• Reseat the battery: Remove the battery pack from the handle, check for dust or debris on the battery contacts and in the battery bay. Wipe contacts with a dry cloth and firmly reinstall the battery until it clicks.
• Reset the battery protection: With the battery removed, press and hold the power button for 10–15 seconds to discharge residual power. Reinsert the battery and try powering on again.
• Test with charger: Plug the charger into the wall, then connect to the vacuum. If the unit powers on only when the charger is connected, the battery pack is likely faulty and should be replaced.
• Inspect for damage: Check the battery casing for swelling, cracks, or burn marks. If any are present, do not use the battery. Replace it with an original Proscenic battery pack of the correct model.
• If E1 persists: The main power board in the handle or the battery BMS (protection board) may be defective. At this point, replacement of the battery pack or main control board is recommended; contact a qualified technician if you are not comfortable opening the handle assembly.