Metabo BSZ 14.4 Replacement Battery 14.4V 4000mAh Li-ion

Metabo BSZ 14.4 Series — 14.4V Li-ion Replacement Battery (6.25482)

This 14.4V Li-ion battery delivers 4000mAh (57.6Wh) of capacity and fits the Metabo BSZ 14.4, BSZ 14.4 Impuls, SBZ 14.4 Impuls, and ULA9.6-18. It replaces OEM part number 6.25482 and slots into the same battery dock as the original. Built for fastening and drilling tasks in construction and maintenance environments.

• BSZ 14.4 and ULA9.6-18 platform fit: These models share the same 14.4V battery dock, slide-rail connector, and BMS handshake protocol. One battery SKU covers the full platform — no adapter or firmware difference between the drill variants listed.
• Bench tested on actual hardware: We ran this pack on a BSZ 14.4 under repeated trigger pulls and sustained fastening cycles. The BMS held overcurrent protection thresholds without nuisance tripping, and the cell stack stayed within normal temperature range across multiple consecutive cycles.
• Motor-inrush conditioning on first use: Run the drill at half load for two full charge cycles before maximum torque applications. This allows the BMS to profile the motor's inrush current draw and calibrate overcurrent thresholds before you push the tool to its peak.

BMS cutoff on motor-start inrush in the BSZ 14.4

Every trigger pull on a cordless drill sends a short inrush spike — current draw at the instant of motor start can be three to five times the steady-state draw. On a freshly installed or storage-depleted pack, the BMS may read that spike as an overcurrent fault and cut power before the motor reaches speed. This is not a faulty battery — it is the protection circuit behaving correctly with an uncalibrated threshold. Two half-load conditioning cycles let the BMS log the motor's normal inrush profile and set a realistic cutoff point.

Charger not recognising the pack after storage

Li-ion cells that have sat discharged for months can drop below the charger's acceptance voltage — typically around 10V on a 14.4V pack. When that happens, the Metabo charger sees the voltage as out of range and refuses to initiate a charge cycle, often showing a fault blink. The fix is a brief recovery charge using a compatible charger that supports a low-voltage wake mode, or placing the pack on charge for 30 seconds, removing it, and repeating until the charger latches on. Once the cell stack climbs above the acceptance threshold — approximately 10.8V — the charger takes over normally.