About this replacement
Black & Decker SZ360 Series — 3.6V Ni-MH Replacement Battery
This is a 3.6V, 2000mAh Ni-MH replacement battery for the Black & Decker SZ360 cordless screwdriver. It fits the SZ360, SZ360 Type 1, and SZ360B. The cell pack slots directly into the screwdriver handle and restores full torque output for light fastening and drilling tasks around the home.
- SZ360, SZ360 Type 1, and SZ360B compatibility: All three variants run the same 3.6V single-rail architecture with an identical connector and cell bay geometry. The Ni-MH chemistry and cell count match the OEM spec, so the BMS communication between pack and charger base behaves as expected out of the box.
- Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the SZ360 platform. The BMS held voltage within the expected 3.6V nominal band under repeated trigger-pull inrush loads, and the charger recognised the pack without faults across all test units.
- First-use cycling on Ni-MH: Ni-MH cells benefit from two or three full charge-discharge cycles before reaching rated capacity. Run the screwdriver at moderate load — not maximum torque applications — for the first two cycles so the cells can reach full electrochemical conditioning before peak demand.
Why the SZ360 bogs under load after sitting unused
Ni-MH cells develop a voltage depression effect after long idle periods — not the same as Li-ion deep discharge, but a real reduction in available current. The internal resistance rises during storage, and when the motor draws its start-up inrush current, the voltage rail sags below what the motor needs for full torque. The fix is a full charge cycle followed by a full discharge under light load, repeated twice. After reconditioning, the cell resistance drops and torque output returns to the rated level.
Charger not recognising the new pack after extended storage
If the replacement pack sat in a warehouse for several months, the resting cell voltage may have dropped below the charger's acceptance threshold. The SZ360 base charger looks for a minimum voltage before initiating the charge cycle — a pack too far below that threshold registers as a fault rather than a flat battery. Place the pack in the charger and watch for LED behaviour over the first five minutes; some units will begin a trickle pre-charge and then switch to full charge once the pack clears the threshold voltage. If the charger shows no response at all, check that the pack terminal voltage reads at least 1.0V per cell — around 3.0V total — with a multimeter before assuming the pack is faulty.