21.6V Rowenta Air Force Light Replacement Battery 3500mAh

Rowenta Air Force Light — 21.6V Li-ion Replacement Battery (FS-9100028994)

This 21.6V, 3500mAh (75.6Wh) lithium-ion battery is a direct replacement for the Rowenta Air Force Light cordless stick vacuum. It fits the MS6573, MS6573WP/BA0, and MS657x series models. Swap it in when your original cell has degraded and suction time has dropped noticeably.

• MS657x platform fit: All MS657x variants share the same 21.6V battery bay, connector pinout, and BMS handshake requirement. A single cell covers the range — no adapter or wiring change needed.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Air Force Light platform. The BMS negotiated correctly with the charger, delivered stable voltage under sustained suction load, and triggered cutoff cleanly at low-cell threshold without nuisance trips.
• Dock charging habit on cordless vacuums: Do not leave the Air Force Light sitting on the charging dock permanently. Continuous trickle charge accelerates capacity fade on lithium cells faster than regular charge-and-remove cycles. Charge to full, then pull it off the dock.

Suction dropping before the battery indicator reaches low

This is voltage sag, not a dead battery. When the filter is partially blocked, the motor draws more current than rated to maintain airflow. That extra draw pulls cell voltage down faster than the indicator predicts. The vacuum feels like it's running out of charge, but the real cause is restricted airflow forcing the motor to work harder. Clean or replace the filter first — if suction holds steady afterward, the battery is not the fault.

Motor cutting out mid-clean and recovering after a short pause

This is a BMS overcurrent trip, not a faulty battery. Sustained restricted suction — usually a clogged filter or blockage in the brush head — causes the motor to draw a spike of current the BMS treats as unsafe. It cuts power to protect the cell, then resets once current demand drops. Clear any blockage, clean the filter, and test again. If the cutout stops, the battery is functioning correctly. If it continues on a clean, unblocked vacuum, check that cell voltage at rest reads above 19V before the next run.