Display shows F4, vacuum runs but battery drains extremely quickly

Safety first: Remove the battery before inspection. Do not open the battery pack.

• Full charge: Charge the battery to 100% on the original Bosch charger until the charger indicates full.
• Full discharge cycle: Use the vacuum continuously on a medium setting until it shuts off by itself. Allow it to rest for 30 minutes, then fully recharge. This can help recalibrate the BMS on some packs.
• Compare runtime: If runtime remains significantly below the specification (e.g., only a few minutes), the battery cells are likely worn out.
• Replace battery: Install a new genuine Bosch battery pack. Avoid cheap third-party packs that may not communicate correctly with the vacuum.
• Check for heat: If the battery becomes very hot during short use, discontinue use and replace immediately.