Vacuum runs but battery indicator behaves erratically; E11 code appears and runtime is much shorter than normal

Safety first: Remove the battery pack before inspecting contacts.

Step-by-step checks:

• 1. Allow cooling: Let the battery rest at room temperature for at least 30 minutes, then reinstall and test. Extreme hot or cold environments can trigger sensor errors.
• 2. Inspect contacts: Look closely at the battery and vacuum contacts. Many packs have separate pins for power and temperature sensing. Clean gently with a dry cloth.
• 3. Test with another battery (if available): If a second Amazon Basics battery works normally without E11, the original pack’s sensor is faulty and the pack should be replaced.

When to stop: If E11 occurs with multiple batteries, the main PCB’s sensor input circuit may be damaged. This requires board-level repair or replacement.