Philips FC6231 Replacement Battery 18.5V 3350mAh Li-ion

Philips FC6231 / FC6331 Series — 18.5V Li-ion Replacement Battery (5ICR19/65-25)

This 18.5V, 3350mAh (61.98Wh) lithium-ion battery replaces the original pack in the Philips FC6231, FC6232, and FC6331 cordless vacuum cleaners. It matches the OEM voltage rail and BMS handshake required by the Philips charging dock. When the original cell degrades and suction becomes inconsistent, this is the direct swap.

• FC6231, FC6232, FC6331 compatibility: These three models share the same 18.5V battery bay, connector pin-out, and BMS communication protocol. A pack built for one works across all three without modification.
• Bench tested on actual hardware: We ran this cell through the Philips charge cycle and monitored BMS communication with the dock. The pack accepted charge without fault codes, and the protection circuit responded correctly to over-discharge cutoff events.
• Dock charging practice for FC-series vacuums: Remove the vacuum from the charging dock once the indicator shows full. Philips FC-series docks supply a continuous trickle current when the vacuum sits connected — leaving it docked indefinitely accelerates capacity fade noticeably faster than cycling the pack through full charge and removal.

Suction dropping before the battery indicator reaches low on the FC6231

The FC6231 motor draws significantly more current when the filter is partially blocked — sometimes two to three times rated draw. The BMS reads this as a high-discharge event and begins throttling output voltage to protect the cell before the fuel gauge registers a low state. The result is noticeably weaker suction while the indicator still shows charge remaining. Cleaning or replacing the filter brings motor draw back to normal and restores full suction at that charge level.

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

This is a BMS overcurrent trip, not a dead battery. When sustained suction restriction forces the motor to pull above the pack's continuous current threshold, the protection circuit opens and cuts power. The brief pause lets the BMS reset and the cell voltage recover slightly above the cutoff threshold. If this happens repeatedly, the root cause is almost always a blocked filter or a partially obstructed inlet — fix the restriction first, then verify cell voltage under load sits above 15V before ruling out a degraded pack.