Eufy HomeVac S11 Go Replacement Battery T2501 25.2V 2500mAh

Eufy HomeVac S11 Series — 25.2V Li-ion Replacement Battery (T2501)

This is a 25.2V, 2500mAh (63Wh) Li-ion replacement battery for the Eufy HomeVac S11 Go, S11 Reach, S11 Infinity, and S11 Lite cordless handheld vacuums. It replaces OEM part number T2501 and fits the same battery slot and connector as the original. Use it to restore suction power when the factory cell no longer holds a full charge.

• S11 series compatibility: The Go, Reach, Infinity, and Lite all share the same 25.2V battery platform, connector pinout, and BMS handshake. Swapping between these models works because the voltage rail and communication protocol are identical across the S11 lineup.
• Bench tested on actual hardware: We ran this cell through charge cycles on an S11 Go and confirmed the BMS negotiated correctly with the charger, passed overcurrent protection thresholds, and held voltage within spec under sustained motor load.
• Dock charging habit on the S11 series: Do not leave the vacuum sitting on the charging dock between every use. The S11 dock does not cut trickle current once the cell is full, and cells left on continuous charge develop capacity fade noticeably faster. Charge to full, then remove it.

Suction dropping before the battery indicator reaches low

The S11's motor draws significantly more current when airflow is restricted — a clogged filter can push draw well above the rated load. The BMS reads this as a voltage sag event and begins throttling motor output to protect the cell, even when the battery itself still has charge. The result is noticeably weaker suction while the indicator still shows two or three bars. Clean the filter first, then retest under the same conditions to confirm whether the issue is the battery or airflow restriction.

Motor cuts out mid-use then recovers after a short pause

This is a BMS overcurrent trip — not a dead battery. When the motor sustains a high draw for several seconds, often caused by a partial blockage or a heavily loaded brush roll, the BMS cuts power to protect the cell. After 10–20 seconds the BMS resets and the vacuum powers back on. If this keeps happening, check for blockages in the inlet nozzle and brush head, and inspect the filter. A genuinely degraded cell with high internal resistance will trigger the same trip at lower loads — check resting voltage, which should read at or above 25.2V after a full charge.