Philips PowerPro Aqua FC6408 25.2V Replacement Battery 2000mAh

Philips PowerPro Aqua FC6408 / FC6409 — 25.2V Li-ion Replacement Battery (300003446961)

This is a 25.2V 2000mAh lithium-ion replacement battery for the Philips PowerPro Aqua and PowerPro Duoa cordless vacuum range. It fits the FC6408, FC6409, FC6171, FC6172, and several additional models in these two series. Voltage and cell count match the original pack exactly.

• PowerPro Aqua and Duoa series fit: These models share the same 25.2V six-cell architecture, connector pinout, and BMS communication protocol. Swapping a pack between them does not require any adapter or modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the FC6408 platform. The BMS handshake completed on first connection, and the charger recognised the pack without error codes or charging interruptions.
• Dock charging habit on cordless vacuums: Do not leave the vacuum sitting on the charging dock continuously. The FC6408 charger does not fully terminate trickle current when the pack is full. Remove the vacuum from the dock once charging completes to protect cell capacity over time.

Suction dropping well before the battery indicator reaches low

This happens when the motor draws more current than the BMS expects, typically because a partially blocked filter forces the motor to work harder. The BMS reads the resulting voltage sag as low charge and reduces power output to protect the cells. The battery gauge is reacting to load, not actual state of charge. Clean or replace the filter, then retest — suction should hold steady through the full charge cycle.

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

This is a BMS overcurrent trip, not a dead battery. When airflow is restricted — by a blocked filter, a tangled brush roll, or a carpet pile that chokes the head — the motor current spikes past the BMS threshold and the pack disconnects to prevent cell damage. The brief pause lets the BMS reset, which is why power returns. Fix the restriction first: check the filter and clear the brush roll. If the trip still occurs on an unobstructed surface, measure pack voltage under load — it should hold above 22V during normal motor start.