Kitfort KT-545 Replacement Battery 14.4V 3400mAh Li-ion

Kitfort KT-545 — 14.4V Li-ion Replacement Battery

This 14.4V, 3400mAh (48.96Wh) lithium-ion battery pack fits the Kitfort KT-545 cordless vacuum cleaner. It replaces the original cell when the pack has degraded and no longer holds a useful charge. The dimensions are 69.00 × 37.60 × 37.30mm — confirm these against your current pack before ordering.

• KT-545 motor rail: The KT-545 runs its brushless motor directly off the 14.4V rail. A replacement cell must hold that rail steady under the surge load at start-up and under sustained suction draw. Voltage sag from an underspec cell causes the motor to cut power mid-use.
• Bench tested on actual hardware: We cycled this pack through repeated start-up loads and sustained draw. The BMS handled overcurrent trips cleanly and reset without requiring a manual cycle. Voltage held within spec across the test range.
• Dock charging habit: Remove the KT-545 from its charging dock once the pack reaches full charge. Leaving it docked continuously pushes trickle current through the cells indefinitely — this accelerates capacity fade faster than normal cycle wear.

Suction dropping before the battery indicator reaches low

This is voltage sag, not a flat battery. When the filter is partially blocked, the motor works harder to pull the same airflow — drawing more current than the cell can deliver cleanly at that state of charge. The voltage rail dips under load, the motor slows, and suction drops noticeably even though the indicator still shows charge remaining. Clean or replace the filter first, then test. If suction holds steady after that, the pack is fine.

Motor cuts out mid-use and then recovers after a few seconds

This is a BMS overcurrent trip. It happens when sustained restricted airflow forces the motor to draw beyond the pack's rated current threshold — the BMS cuts the output to protect the cells, then resets once the load clears. It is not a faulty battery. Check the filter and the suction path for blockages before replacing the pack. If the motor cuts out on an unobstructed run, the original cell's BMS threshold has degraded and replacement is the correct next step.