Philips FC6231 18.5V Replacement Battery 2600mAh Li-ion

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

This is an 18.5V 2600mAh (48.1Wh) lithium-ion battery pack for the Philips FC6231, FC6232, and FC6331 cordless stick vacuums. It replaces OEM part number 5ICR19/65-25 directly. If the original pack is no longer holding charge, this is the direct swap.

• FC6231, FC6232, FC6331 compatibility: These three models share the same 18.5V battery bay, connector pin layout, and BMS handshake protocol. A battery that works on one will work across all three without modification.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on an FC6231 unit. The BMS communicated correctly with the charger, protection thresholds triggered at expected voltages, and the charge indicator behaved normally throughout.
• Dock charging on these vacuums: Do not leave the vacuum sitting on the charging dock continuously. These models trickle-charge when left docked indefinitely, which accelerates cell capacity fade. Charge to full and remove the vacuum from the dock.

Suction dropping before the battery indicator reaches low

The FC6231 motor draws significantly more current when the filter is partially blocked. Under that extra load, cell voltage sags earlier than the indicator expects, causing the motor to slow before the LED signals low battery. This looks like a weak battery but is often a filter restriction problem. Clean or replace the filter first — if suction and runtime return to normal, the battery is not the cause. If sag continues on a clean filter, the cells have lost capacity and replacement is needed.

Motor cuts out mid-clean and then restarts after a pause

This is a BMS overcurrent trip, not a charger or dock fault. When the vacuum runs over thick carpet or picks up a concentrated blockage, current draw spikes briefly above the BMS protection threshold. The pack cuts power to protect the cells, then resets after a short cool-down. If this happens repeatedly on a fresh battery, inspect the dust canister and filter for restriction — sustained blockage keeps draw elevated. A pack with degraded cells will trip more easily under the same load because internal resistance is higher, so frequent cut-outs on an older battery usually confirm the cells need replacing.