About this replacement
Twinbird HC-4326P Series — 7.2V Ni-MH Replacement Battery (HC-4326)
This is a 7.2V 2000mAh Ni-MH replacement battery for the Twinbird HC-4326P cordless handheld vacuum and related models. It fits the HC-4326BL, HC-4326DGY, and HC-4324, among others. Swap it in when the original cell can no longer hold enough charge to complete a cleaning session.
- HC-4326 series compatibility: These models share the same 7.2V motor rail, connector format, and cell count, so one battery pack covers the full range. Variants differ in colour, not internal spec.
- Bench tested on actual hardware: We cycled this pack through discharge under motor load and confirmed the BMS holds voltage steady until the cell is genuinely depleted — no early cutoff on a clean filter.
- Dock charging habit on this vacuum: Do not leave the HC-4326P sitting on the charging dock continuously. Ni-MH cells in this pack degrade faster under constant trickle charge than under normal use cycles. Charge fully, then remove the unit from the dock.
Suction dropping before the battery indicator reaches low
This happens because motor current draw rises sharply when the filter is partially blocked. The BMS reads that spike as a low-cell condition and throttles output voltage early. The battery indicator tracks voltage, not actual cell capacity — so it can still show mid-range while suction has already dropped. Clean the filter first; if suction recovers, the pack is fine. If suction stays weak on a clean filter, cell capacity has genuinely faded and replacement is the fix.
Motor cutting out mid-use and then recovering after a short pause
This is a BMS overcurrent trip, not a wiring fault. When restricted airflow forces the motor to draw sustained high current, the BMS cuts the circuit to protect the cells. Resting the unit for 30–60 seconds lets the BMS reset and allows the cell voltage to recover slightly above the trip threshold. If this happens repeatedly, remove and inspect the filter — a clogged filter is almost always the root cause. A fully healthy pack on a clean filter should hold 7.2V under normal vacuum load without tripping.