Kärcher K55 Replacement Battery 4.8V 3000mAh 4KR-1500SC/V

Karcher K55 / Broom K55 — 4.8V Ni-MH Replacement Battery (4KR-1500SC/V)

This is a 4.8V, 3000mAh Ni-MH battery pack for the Karcher K55 and Broom K55 cordless handheld vacuums. It replaces OEM part 4KR-1500SC/V directly. The pack restores power to the vacuum motor when the original cell has degraded and no longer holds a usable charge.

• K55 and Broom K55 fitment: Both models share the same 4.8V four-cell NiMH pack format, identical connector pinout, and the same charge-termination profile. One battery covers both variants without modification.
• Bench tested on actual hardware: We cycled this pack through full charge and draw tests on a K55 unit. The BMS held stable voltage across the motor's operating range and terminated charge correctly at full capacity without overrun.
• Dock charging habit on the K55: Do not leave the K55 sitting on the charging dock permanently. Continuous trickle charge on NiMH cells accelerates capacity fade faster than normal cycle wear. Charge to full, then remove the unit from the dock until the next use.

Suction dropping before the battery indicator reaches low on the K55

This happens when the motor draws more current than rated — usually because the filter is partially blocked. A restricted airflow path forces the motor to work harder, pulling higher current from the pack and causing voltage to sag under load. The indicator reads the resting voltage, not the load voltage, so it shows more charge than the motor can actually use. Clear the filter and check the dust bin before assuming the battery is at fault.

K55 motor cuts out mid-clean then recovers after a short pause

This is a BMS overcurrent trip, not a dead battery. When suction is restricted — blocked filter, full bin, or a carpet snag — the motor spikes current demand beyond the pack's continuous output threshold. The BMS cuts the circuit to protect the cells, then resets once current demand drops. Clean the filter and empty the bin first. If the fault continues on a clear filter, measure pack voltage under load — it should hold above 4.2V during normal motor operation.