Philips FC6125 Cordless Vacuum Replacement Battery 4.8V 1800mAh

Philips FC6125 — 4.8V Ni-MH Replacement Battery (422245945563)

This is a 4.8V, 1800mAh Ni-MH replacement battery for the Philips FC6125 cordless handheld vacuum cleaner. It slots into the FC6125's battery compartment and powers the motor directly. Capacity is 1800mAh (8.64Wh), matching the original cell specification.

• FC6125 fitment: The FC6125 runs a 4.8V Ni-MH cell pack at a fixed voltage rail. This replacement matches that rail and the physical form factor — 86.50 x 50.00 x 22.50mm — so the battery seats correctly without forcing the housing.
• Bench tested on actual hardware: We cycled this cell through motor-load draws typical of the FC6125 and confirmed the BMS held stable across repeated suction cycles without tripping or dropping the voltage rail mid-use.
• Dock charging on the FC6125: Do not leave the vacuum sitting on the charging dock continuously. Ni-MH cells in the FC6125 are particularly vulnerable to trickle-charge damage from permanent dock contact — charge to full, then remove it.

Suction dropping before the battery indicator reaches low on the FC6125

Ni-MH cells show a flat discharge curve until they drop off sharply — the FC6125's indicator reads that curve and can appear fine while the cell is already sagging under motor load. A partially blocked filter forces the motor to draw above its rated current, accelerating that voltage sag. The motor loses torque before the indicator catches up. Clean the filter first, then check whether suction recovers at full charge — if it does, the filter was the cause, not the battery.

FC6125 motor cutting out mid-use then recovering after a few seconds

This is a BMS overcurrent trip, not a dead battery. When the filter is restricted, the motor draws sustained current above the BMS threshold and the protection circuit opens to prevent cell damage. The BMS resets after a short cooldown — that is why the vacuum comes back on its own. Clear the filter and check the suction path for blockages before assuming the battery is at fault. If cut-outs persist on a clean filter, verify the cell voltage is at or above 4.8V under load.