About this replacement
Philips SpeedPro Max Series — 18V Li-ion Replacement Battery (IP827)
This 18V Li-ion battery replaces the IP827 cell pack in the Philips SpeedPro Max and SpeedPro Max Aqua cordless stick vacuums. It fits FC6801, FC6812, and related models in that line. Capacity is 3400mAh (61.2Wh), matching the original specification.
- SpeedPro Max and Aqua compatibility: These models share the same 18V battery bay, connector pinout, and BMS handshake requirements — the IP827 part number covers the full FC68xx series without modification.
- Bench tested on actual hardware: We ran this cell pack through charge and discharge cycles on a SpeedPro Max unit. The BMS accepted the charger handshake immediately, voltage held steady across motor start and sustained suction, and protection circuitry tripped correctly at the low-cell threshold.
- Dock charging habit on the SpeedPro Max: The SpeedPro Max charging dock does not cut power once the battery reaches full charge — leaving the vacuum docked permanently exposes the cells to continuous trickle current. Charge to full, then remove the vacuum from the dock until the next use.
Suction dropping before the battery indicator reaches low
This happens when the motor is working harder than rated — usually because a partially blocked filter forces higher current draw to maintain airflow. The BMS reads the increased load as a voltage sag event and begins throttling motor power before the fuel gauge registers a low charge state. The battery itself is not failing; the motor is drawing more current than the pack can sustain cleanly under restriction. Clean or replace the filter first, then retest — sustained suction should stabilise above 15V under load.
Motor cuts out mid-clean and then recovers after a few seconds
This is a BMS overcurrent trip, not a flat battery. It triggers when sustained restricted airflow — from a blocked filter, full dust bin, or a floor nozzle clog — causes the motor to spike current past the pack's protection threshold. The BMS shuts the output down briefly to protect the cells, then resets once current demand drops. Clear the blockage, empty the bin, and check that the filter is seated correctly before restarting the vacuum.