Kärcher VC4 25.2V Replacement Battery 9.754-156.0

Karcher VC4 — 25.2V Li-ion Replacement Battery (9.754-156.0)

This 25.2V 2500mAh lithium-ion battery replaces the original Karcher 9.754-156.0 cell pack in the VC4 cordless handheld vacuum cleaner. It matches the voltage rail and connector configuration of the OEM pack. Capacity is 2500mAh (63Wh) — identical to the factory specification.

• VC4 platform fit: The VC4 runs a 25.2V 6S lithium cell stack. This replacement matches that stack configuration, so the BMS handshake with the charger completes correctly. A voltage mismatch here will cause the charger to reject the pack entirely.
• Bench tested on actual hardware: We ran this pack through charge cycles on a VC4 charger and confirmed BMS communication, charge acceptance, and full discharge under motor load. The overcurrent protection tripped correctly under a simulated blockage and reset without requiring a power cycle.
• Dock charging on the VC4: Do not leave the VC4 sitting on the charging dock continuously. Cordless vacuums on permanent dock charge develop capacity fade faster than units charged only when depleted. Charge the pack to full, then remove it from the dock.

Suction dropping before the battery indicator reaches low on the VC4

This happens when the motor draws more current than rated — typically caused by a partially blocked filter or a restricted nozzle, not a failing battery. Under elevated load, the BMS reads an overcurrent condition and reduces power to protect the cell stack. The result feels like a weak battery but the charge level indicator may still show mid-range. Clear the filter first, then check whether suction returns to full strength at the same charge level.

VC4 motor cuts out mid-use and then recovers after a pause

This is a BMS overcurrent trip, not a battery fault. When suction is sustained against a blockage — a clogged filter, a jammed nozzle, or dense carpet pile — motor current spikes above the BMS threshold and the pack shuts the output rail. A short pause lets the BMS reset and power returns. Fix the restriction rather than the battery: clean or replace the filter, clear the nozzle path, then retest. If the cutout persists on a clean filter, check cell voltage at the pack terminals — a healthy cell at moderate charge should read above 22V under light load.