Cordless vacuum shows E10 and will not power on after long storage

Safety first: Do not attempt to open or jump‑start the battery pack. Deeply discharged Li‑Ion cells can be hazardous.

• Try standard charging: Place the battery on the original Kärcher charger for at least 2–3 hours, even if no LEDs light initially. Some packs need time to wake from protection mode.
• Check charger output: Verify the charger LED behavior with another known-good battery if available. Replace the charger if it does not charge any battery.
• Inspect battery for damage: If the pack is swollen, cracked, or shows signs of overheating, do not use it. Dispose of it according to local regulations.
• If E10 remains after extended charging: The battery pack’s protection/BMS circuit has likely locked out permanently or cells are damaged. Replace the battery pack with an original Kärcher unit.