Philips SpeedPro 21.6V Replacement Battery 2500mAh

Philips SpeedPro / SpeedPro Aqua — 21.6V Li-ion Replacement Battery (INR18650C25)

This is a 21.6V, 2500mAh Li-ion replacement battery for the Philips SpeedPro and SpeedPro Aqua cordless stick vacuums. It fits FC6726/01, FC6725/01, and a further 16 confirmed models in the SpeedPro range. When the original cell degrades and suction drops noticeably on a full charge, this is the direct swap.

• SpeedPro and SpeedPro Aqua compatibility: Both the dry and wet-dry SpeedPro variants run the same 21.6V battery rail and share the same connector and BMS handshake, which is why one cell covers both lines. The Aqua model adds a roller brush motor, so its peak draw is slightly higher — the BMS on this cell handles that without tripping under normal use.
• Bench tested on actual hardware: We cycled this battery through the SpeedPro platform under full suction load. The BMS held voltage within the expected window across multiple discharge cycles and returned a clean charge acceptance each time without error flags from the charger.
• Dock charging habit on SpeedPro: Do not leave the vacuum sitting on the charging dock indefinitely between uses. SpeedPro docks do not cut trickle current reliably once the cell is full. Charge to full, then remove from the dock — this alone has the biggest effect on long-term capacity retention.

Suction dropping before the battery indicator reaches low

This is a voltage sag issue, not a capacity issue. When the motor encounters increased resistance — a partially blocked filter, a dense carpet pile, or a restricted inlet — it pulls more current than rated. The battery voltage dips under that load before the state-of-charge indicator registers as low. The vacuum loses suction but the LED still shows two or three bars. Cleaning or replacing the filter first eliminates the most common cause before attributing the drop to the battery itself.

Motor cuts out mid-clean then restarts after a few seconds

This is a BMS overcurrent trip, not a faulty battery. Sustained restricted airflow — most often from a clogged filter or blocked brush roll — forces the motor to draw current above the BMS protection threshold. The BMS cuts power to protect the cell, then resets once current demand drops. If the motor restarts cleanly after a short pause, confirm the filter is clear and the brush roll spins freely before assuming the cell is defective. A clear airpath keeps draw within the 21.6V system's rated current envelope.