Tefal TY6541 Cordless Vacuum Replacement Battery 14.4V 3500mAh

Tefal TY6541 / TY6543 Series — 14.4V Li-ion Replacement Battery

This is a 14.4V 3500mAh lithium-ion replacement battery for Tefal cordless stick vacuum cleaners including the TY6541, TY6541KM/BA0, TY6543, and TY6543KL/BA0 series. It replaces the original power cell when capacity has faded and the vacuum can no longer hold a useful charge. Voltage and connector match the original pack so it seats and communicates with the vacuum's onboard electronics.

• TY6541 and TY6543 platform compatibility: Both model lines share the same 14.4V battery bay, connector pinout, and BMS handshake protocol — that is why a single cell covers the full range. Different suffix variants (KM, KL, BA0) reflect regional market packaging, not electrical differences.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on TY6541-platform hardware. The BMS initialised cleanly on first contact, charge acceptance was normal, and the protection circuit tripped correctly at low-voltage cutoff without requiring a manual reset.
• Dock charging habit on stick vacuums: Do not leave this vacuum on the charging dock permanently. Continuous dock connection keeps the cell in a trickle-charge state that accelerates capacity loss. Charge fully, then remove the vacuum from the dock until the next use.

Suction dropping before the battery indicator reaches low

This happens when the motor draws more current than the battery can deliver at its present state of charge — voltage sags under load before the indicator logic registers a low-battery event. A partially clogged filter is the most common trigger: restricted airflow forces the motor to work harder, spiking current draw. Clean or replace the filter first. If suction recovers, the filter was causing the voltage sag, not a faulty cell. If the problem persists with a clean filter, check resting cell voltage — a healthy 14.4V pack should read at least 15.8V off the charger.

Motor cuts out mid-clean then restarts after a short pause

This is a BMS overcurrent trip, not a charger or contact fault. When suction is blocked — by a full dust cup, a clogged filter, or hair wrapped around the brush roll — the motor stalls briefly and current spikes past the BMS protection threshold. The BMS cuts power, the vacuum goes silent, and it resets after a few seconds of rest. Clear the blockage, empty the dust cup, and clean the filter before resuming. If trips continue on an unobstructed vacuum, the cell may be too degraded to deliver rated current — replace the battery.