About this replacement
Karcher VC 4i / VC 4i Plus — 18V Li-ion Replacement Battery (9.764-882.0)
This 18V 3000mAh (54Wh) lithium-ion battery fits the Karcher VC 4i, VC 4i Plus, and VC 4i Cordless handheld vacuum cleaners. It replaces OEM part numbers 9.764-882.0 and 9.764-938.0. The battery slots directly into the same compartment as the original and connects to the vacuum's BMS handshake circuit.
- VC 4i platform compatibility: The VC 4i, VC 4i Plus, and VC 4i Cordless all share the same 18V battery rail, connector footprint, and BMS communication protocol — that is why one battery covers the entire range including model 064200.
- Bench tested on actual hardware: We ran this cell through sustained motor-load cycles on the VC 4i platform and monitored BMS response under restricted airflow conditions. The protection circuit held within the expected overcurrent threshold and did not nuisance-trip during normal vacuuming loads.
- Dock charging on the VC 4i: Do not leave the vacuum sitting on the charging dock permanently. The VC 4i charger does not drop to a true maintenance mode once full — continuous dock time accelerates cell capacity fade. Charge to full, then remove.
Suction dropping before the battery indicator reaches low on the VC 4i
This happens when the motor draws higher current than rated — usually because the filter is partially blocked. A restricted filter forces the motor to work harder, which pulls more amps and causes the battery voltage to sag under load. The BMS reads that voltage sag and throttles output before the indicator gauge catches up. Clean or replace the filter first — if suction recovers and holds, the battery is fine.
Motor cuts out mid-use then restarts after a few seconds
This is a BMS overcurrent trip, not a dead cell. When suction is blocked — by a clogged filter, a blocked nozzle, or thick carpet fibres — motor current spikes sharply. The BMS cuts output to protect the cells, then resets once current drops. The fix is to clear the restriction and let the battery rest for 10–15 seconds before restarting. If it trips repeatedly on an unblocked vacuum, check that the cell voltage is above 15V under load before assuming the battery is at fault.