About this replacement
Metabo BSZ 14.4 Series — 14.4V Ni-MH Replacement Battery (6.25475)
This is a 14.4V, 2100mAh Ni-MH replacement battery for the Metabo BSZ 14.4 and BSZ 14.4 Impuls cordless drills, as well as the SBZ 14.4 Impuls. It replaces OEM part numbers 6.25475, 6.25476, and ME1474. Capacity figure comes from the product data — 30.24Wh total energy.
- BSZ 14.4 and SBZ 14.4 Impuls compatibility: All models in this group share the same 14.4V rail, slide-in connector format, and BMS handshake protocol. Swapping between BSZ and SBZ variants works without modification because the pack form factor and communication pin layout are identical across the range.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a Metabo 14.4V platform. The BMS handled motor inrush current without nuisance tripping, and cell temperature stayed within spec under repeated trigger pulls at load.
- Ni-MH break-in on the Metabo 14.4V platform: On first use, run the drill at half load for two cycles before maximum torque applications. This allows the BMS to profile the motor inrush draw and set accurate overcurrent thresholds before you push the tool hard.
BMS cutoff on motor-start inrush with the BSZ 14.4
Cordless drills draw a sharp current spike the moment the trigger closes — especially under load or when driving large fasteners into hardwood. On the Metabo BSZ 14.4, this inrush spike can briefly exceed 10A before the motor reaches operating speed. A freshly installed Ni-MH pack has not yet profiled this draw pattern, so the BMS may trip the overcurrent threshold prematurely. Running two break-in cycles at reduced load gives the BMS enough data to distinguish normal inrush from a genuine fault condition.
Tool bogs and loses torque mid-fastener even with a charged pack
This is voltage sag — the pack voltage drops under sustained draw faster than the cells can recover. On Ni-MH cells, sag is made worse by high contact resistance at the slide-in rail, particularly if terminals are corroded or spring tension has weakened. Clean the pack terminals and tool contacts with a dry cloth, then check that the pack clicks fully into the rail with firm spring engagement. If sag continues after cleaning, check open-circuit voltage — a healthy 14.4V Ni-MH pack should read at or above 15.6V immediately after a full charge.