About this replacement
Karcher KC55 Cordless Vacuum — 4.8V Ni-MH Replacement Battery (28100010)
This is a 4.8V, 3000mAh Ni-MH replacement battery for the Kärcher KC55 handheld vacuum cleaner and K55 Cordless Electric Broom. It replaces OEM part numbers 28100010, 6.654-118.0, and GP 160SCHE. Fit models include KC55, 1.258-505.0, and 1258-5050 variants.
- KC55 and K55 Cordless Broom compatibility: These models share the same 4.8V cell pack configuration, connector footprint, and BMS handshake requirements. The motor controller expects a specific voltage rise profile on startup — this cell pack matches that curve.
- Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on a KC55 unit. The BMS held cutoff correctly at low-cell voltage, and the motor drew within rated current on both hard floor and simulated carpet load.
- Dock charging behaviour on the KC55: Do not leave the KC55 on the charging dock permanently. Ni-MH cells in this vacuum develop capacity fade significantly faster under continuous trickle charge. Charge to full, then remove from the dock until the next use.
Suction dropping before the battery indicator reaches low on KC55
This happens when the motor is pulling more current than the cell pack can sustain under load — voltage sags early even though the indicator still reads mid-range. A partially blocked filter is the most common trigger. With restricted airflow, the motor works harder, draws more current, and the cell voltage drops faster than the indicator expects. Clean or replace the filter first, then test the battery under normal load to confirm whether the pack itself needs replacing.
KC55 motor cutting out mid-clean and then recovering after a pause
This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage or a clogged filter, current draw spikes above the pack's safe threshold and the BMS shuts the circuit. After a short rest, the BMS resets and the motor starts again. The fix is clearing the blockage or replacing the filter — not the battery. If the cutout continues with a clean filter and no blockage, test cell voltage at rest; it should read above 4.6V on a fully charged pack.