iRobot Roomba 400 Replacement Battery 14.4V 2000mAh 11700

iRobot Roomba 400 Series — 14.4V Ni-MH Replacement Battery (11700)

This 14.4V 2000mAh Ni-MH battery replaces the original cell pack in the iRobot Roomba 400 series robotic vacuum. It fits the Roomba 400, 4000, 4905, APS 4905, and over 29 additional models that share the same voltage rail and connector. Drop capacity is matched to the OEM specification at 2000mAh (28.8Wh).

• Roomba 400 series platform fit: Every model in this lineup runs the same 14.4V battery bus, uses the same physical connector, and communicates with the same BMS logic — so one cell pack covers the full range without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the Roomba 400 platform. The BMS accepted the handshake without fault codes, and current draw under motor load stayed within the rated window across multiple cleaning passes.
• Dock charging behaviour on Ni-MH cells: Do not leave the Roomba sitting on the dock between cleaning sessions. Ni-MH cells are particularly vulnerable to trickle-charge damage from continuous dock contact — charge fully, then remove the unit from the dock until the next run.

Suction dropping before the battery indicator reaches low

The Roomba's motor draws significantly more current when the filter is partially blocked or airflow is restricted. Under that increased load, the cell voltage sags early — the indicator still reads mid-range, but the motor no longer receives enough voltage to maintain suction pressure. This is a load-sag issue, not a capacity issue. Clean the filter and check the brushroll for hair wrap before concluding the battery is at fault.

Motor cutting out mid-cycle and then recovering on its own

This pattern points to a BMS overcurrent trip rather than a dead cell. When the brushroll or intake is obstructed, sustained high current triggers the BMS protection circuit, which cuts power momentarily then resets. The unit resumes once the trip clears, giving the impression of a faulty battery. Clear any blockage at the brushroll and intake port, then verify the filter is clean — overcurrent trips should stop once airflow restriction drops back within the motor's rated draw.