About this replacement
iRobot Braava Jet 240 Series — 3.6V Li-ion Replacement Battery (4446040)
This 3.6V, 2900mAh Li-ion battery replaces part number 4446040 in the iRobot Braava Jet 240, 241, 244, and 245 floor mopping robots. It fits the same connector and BMS interface as the original cell. Capacity is rated at 10.44Wh, matching the stock specification from the factory.
- Braava Jet 240 series compatibility: The 240, 241, 244, and 245 share the same battery bay geometry, connector pinout, and BMS handshake protocol. A single cell covers all four variants without modification.
- Bench tested on actual hardware: We cycled this battery through the Braava Jet 240's standard wet-mopping sequence. The BMS held stable voltage across both spray-and-scrub and dry-sweep modes, with no mid-cycle cutoff detected.
- Avoid leaving the Braava Jet 240 on its charging pad indefinitely: This robot uses a trickle-hold charge once full. Extended dock time at 100% accelerates Li-ion cell degradation — charge the unit, then remove it from the pad once the indicator confirms full charge.
Why the Braava Jet 240 stops mid-clean without a low-battery warning
The Braava Jet 240's BMS monitors cell voltage in real time. When an aging cell drops voltage faster than the indicator circuit can update, the robot shuts down before the low-battery LED triggers. This is a BMS protection event, not a sensor fault. A degraded cell can read 30–40% capacity on the indicator yet collapse under the spray-pump and drive-motor load simultaneously. Replacing the cell resolves the mismatch between reported and actual state of charge.
Braava Jet 240 not responding to charger after long storage
Li-ion cells left discharged for extended periods drop below the BMS recovery threshold — typically around 2.5V per cell. At that voltage, the protection circuit locks out charging as a safety measure. Some chargers will not attempt a recovery charge and simply show no activity. To attempt recovery, connect the robot to the official charger and leave it for 30–60 minutes without interruption — some BMS units will trickle-wake from a near-zero state. If the charger still shows no response after that window, the original cell is beyond recovery and replacement is the correct next step.