About this replacement
Media QN8 — 21.6V Li-ion Replacement Battery (6INR18650)
This is a 21.6V 2000mAh Li-ion replacement battery for the Media QN8 cordless vacuum cleaner. It fits the QN8 stick and handheld configuration and restores suction power when the original cell has degraded. Capacity is 2000mAh (43.2Wh) — matching the factory specification.
- QN8 platform fit: The QN8 runs a 21.6V cell string using the 6INR18650 configuration — six 18650 cells wired in series. The BMS in this pack matches that voltage rail and connector arrangement, so the vacuum's power management system recognises it correctly.
- Bench tested on actual hardware: We cycled this pack through full discharge under simulated floor-head load and monitored BMS response. Cell voltage balance held across the string, and the protection circuit tripped cleanly at the low-voltage cutoff threshold without stalling the motor mid-cycle.
- Dock charging habit on the QN8: Do not leave the QN8 sitting on its charging dock between every use. Continuous dock connection keeps the cells at float charge and accelerates capacity fade. Charge fully, then disconnect — reconnect only when the battery needs a full cycle.
Suction dropping before the battery indicator reaches low
This happens when the motor draws higher current than rated — usually because a partially blocked filter forces the motor to work harder. The increased draw causes voltage to sag across the cell string earlier than the indicator predicts. The indicator reads state-of-charge at rest voltage, not under load, so it lags behind real-world capacity under strain. Clean or replace the filter first — if suction still drops early, the cell string itself may have degraded below 2000mAh.
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, stuck debris in the head, or a clogged cyclone — the motor spikes its current draw to compensate. The BMS reads that spike as an overcurrent fault and shuts the cell string down. After a few seconds the BMS resets and the motor restarts. Clear the blockage before the next run; if the trip keeps happening on a clean filter, check that cell voltage at rest is above 18V before charging.