Ecovacs Winbot Mini Replacement Battery 3.7V 3400mAh

Ecovacs Winbot Mini / W1S / W2 Pro — 3.7V Li-ion Replacement Battery (201-2432-0438)

This 3.7V, 3400mAh Li-ion cell replaces the factory battery in the Ecovacs Winbot Mini, Winbot W1S, and Winbot W2 Pro window cleaning robots. It also cross-references OEM part S32-LI-36-3000. The battery powers the suction motor and drive system that keeps the unit adhered to and moving across glass surfaces.

• Winbot Mini, W1S, and W2 Pro compatibility: All three models share the same 3.7V single-cell architecture, connector pinout, and BMS communication protocol — which is why one cell covers the full range. Swapping between these models does not require firmware changes or adapter cables.
• Bench tested on actual hardware: We cycled this cell through repeated suction-motor start loads and confirmed the BMS handled inrush current without tripping. Discharge curves stayed within spec across multiple cycles, and the protection circuit responded correctly to simulated over-discharge conditions.
• Winbot storage between cleaning sessions: If the robot sits unused for more than two weeks, discharge it to around 50% before storing. Leaving it fully charged for extended periods accelerates lithium plating and causes irreversible capacity loss faster than regular use would.

Why the Winbot cuts out mid-clean and re-attaches to the glass

The Winbot's suction pad must maintain constant negative pressure to stay on the glass. When the battery voltage sags under combined drive-motor and suction-motor load, the BMS can briefly cut output to protect the cell. The robot loses suction, triggers its safety tether, and halts. This is more common toward the end of a battery's service life, when internal resistance has risen enough that high-draw moments cause a sharper voltage drop than the BMS tolerates.

Replacement battery shows full charge instantly but drains within minutes of use

This usually means the charger completed a voltage-based cutoff without fully conditioning the new cell — common when a deeply discharged OEM battery was swapped without a full charge cycle first. The new cell's BMS may also need a complete charge-discharge cycle before its state-of-charge reporting calibrates correctly. Run one full charge from flat to 100% before judging actual capacity. Confirm the charger output reaches 4.2V at the charging contacts before assuming a fault with the cell.