Kärcher 25.2V Cordless Vacuum Replacement Battery 3000mAh

Karcher FC 5 Cordless Series — 25.2V Li-ion Replacement Battery (0320-015217)

This 25.2V 3000mAh Li-ion battery replaces the OEM pack in Karcher's FC 5 Cordless, Basic FC 5 Cordless, FC5, and 1.055-601.0 floor cleaner range. It matches the original voltage rail, cell count, and BMS communication profile. Capacity is 3000mAh (75.6Wh), taken directly from product specification — not estimated.

• FC 5 Cordless platform fit: These models share a common 25.2V six-cell Li-ion architecture, the same physical connector housing, and an identical BMS handshake. A pack built to a different voltage rail or missing the correct BMS signal will be rejected by the charger or fail to spin the motor.
• Bench tested on actual hardware: We cycled this pack through the FC 5 Cordless charge and discharge sequence. The BMS accepted the charger handshake cleanly, cell balancing engaged on the first charge, and no overcurrent trip occurred under sustained motor load on hard floor mode.
• Dock charging discipline for FC 5 Cordless: Do not leave the vacuum on the charging dock permanently. FC 5 Cordless units on continuous dock charge develop capacity fade significantly faster than those charged only when depleted. Charge to full and remove from the dock.

Suction dropping before the battery indicator reaches low on the FC 5 Cordless

The FC 5 Cordless motor draws noticeably more current when the filter or dirty water tank is partially restricted. As current draw rises, cell voltage sags under load — and the BMS reads that sag as a low-charge condition even when state of charge is still adequate. The result is reduced motor speed and weaker suction well before the indicator warns you. Clean or replace the microfilter and check the dirty water tank outlet first — this restores normal current draw and the voltage sag disappears.

Motor cutting out mid-clean and then recovering after a few seconds

This is a BMS overcurrent trip, not a flat battery. When airflow through the FC 5 Cordless is restricted — blocked filter, full tank, or a clog at the nozzle — the motor works harder to maintain suction, draws above the BMS overcurrent threshold, and the pack cuts power to protect the cells. The BMS resets automatically after a short thermal delay, which is why power returns a few seconds later. Clear the restriction, confirm the filter is seated correctly, and check that the dirty water tank drain is unobstructed before restarting.