About this replacement
Shark IX140H / IZ340H Series — 21.6V Li-ion Replacement Battery (XFBT650)
This is a 21.6V 1800mAh Li-ion replacement battery for the Shark IX140H, IX141H, and IZ340H cordless stick vacuums. It uses OEM part number XFBT650 and slots directly into the battery bay on these models. Capacity is 1800mAh (38.88Wh) — sourced from product data, not estimated.
- IX140H, IX141H, and IZ340H compatibility: These three models run the same 21.6V battery rail and share the XFBT650 form factor, connector pinout, and BMS handshake protocol — swapping between them works without modification.
- Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on an IX140H. The BMS negotiated correctly with the charger, held voltage through a sustained motor-load test on carpet mode, and triggered overcurrent protection cleanly under a blocked-filter stress test.
- Dock charging on the IX140H / IZ340H: Do not leave the vacuum sitting on the charging dock permanently. These models have no dock-side charge termination — the battery stays in a trickle state the entire time, which accelerates capacity fade. Charge to full, then remove from the dock.
Suction dropping before the battery indicator reaches low
On the IX140H and IZ340H, the battery indicator reads remaining charge — not motor voltage under load. When a filter is partially blocked or the dust cup is full, motor current draw spikes above the rated level. The BMS responds by pulling back the voltage it delivers to the motor, which drops suction noticeably while the indicator still shows two or three bars. The fix is not the battery — clean the filter and empty the dust cup, then recheck. If suction recovers immediately, the battery and BMS are both functioning correctly.
Motor cuts out mid-clean and restarts after a few seconds
This is a BMS overcurrent trip, not a dead battery. On sustained restricted airflow — packed filter, blocked floor head, or wedged debris — the motor pulls more current than the BMS threshold allows. The BMS opens the output circuit to protect the cells, which feels like a sudden shutoff. After a few seconds the BMS resets and the vacuum restarts. Clear the blockage completely and confirm the post-motor filter is seated correctly. If the cutout stops, the battery is not at fault.