About this replacement
WOMOW S22 Tech — 21.6V Li-ion Replacement Battery (FC-2012D)
This is a 21.6V Li-ion replacement battery for the WOMOW S22 Tech cordless stick vacuum. It carries a 2500mAh (54Wh) capacity and uses OEM part number FC-2012D. It fits the S22 Tech platform directly — no modification needed.
- S22 Tech platform fit: The S22 Tech runs a 21.6V motor rail with a BMS that monitors cell voltage and current draw across both handheld and stick configurations. This battery matches that voltage and connector spec, so the BMS accepts it without fault codes or cutoffs on startup.
- Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on the S22 Tech motor. The BMS handled inrush current at motor start cleanly and held voltage above the cutoff threshold through the full discharge curve without tripping.
- Dock charging on the S22 Tech: Do not leave the S22 Tech sitting on its charging dock permanently. Continuous dock charge on Li-ion cells causes capacity fade faster than normal use cycles. Charge to full, then remove the vacuum from the dock until the next clean.
Suction dropping before the battery indicator shows low
This happens when motor current draw climbs due to a blocked filter or restricted airway. The BMS sees the extra load, voltage sags under load, and the motor slows — even though resting cell voltage still reads fine. The indicator reads resting voltage, not loaded voltage, so it lags behind real capacity. Check and clean the filter first. If suction restores, the battery was not the issue.
Motor cutting out mid-clean then recovering after a pause
This is a BMS overcurrent trip, not a dead battery. When airflow is restricted — blocked filter, clogged brush roll, or sealed inlet — the motor draws sustained current beyond the BMS threshold and the circuit cuts. Resting for 30–60 seconds lets the BMS reset and the cell cool. Clear the blockage before restarting. If the trip repeats on a clean filter, verify cell voltage under load sits above 18V.