About this replacement
Black&Decker Cordless Grass Shear — 3.6V Ni-MH Replacement Battery
This is a 3.6V 2200mAh Ni-MH replacement battery pack for the Black&Decker GS500 cordless grass shear. The GS500 uses a compact 3-cell sub-C configuration to power its trimming blade, and this pack matches that voltage rail and physical footprint exactly. Capacity is rated at 2200mAh — a slight step up from the original 2000mAh spec.
- GS500 compatibility: The GS500 runs a single 3.6V battery bay with a fixed connector orientation — this pack matches the voltage, cell count, and connector used across that model line.
- Bench tested on actual hardware: We ran full charge and discharge cycles through the pack — the BMS held voltage steady under blade load and cut off cleanly at the low-voltage threshold without tripping the shear's protection circuit.
- First charge matters with Ni-MH: Run two or three full charge and discharge cycles before expecting full capacity — Ni-MH cells need conditioning to reach their rated output after sitting in storage.
Why sub-C cells in a grass shear
Sub-C cells pack a high current-delivery surface area into a small cylinder, which suits the GS500's burst-load cutting pattern. Grass shears draw hard during each blade stroke, then idle briefly — Ni-MH handles that pulse-and-recover cycle better than older NiCd chemistry. The 2200mAh rating reflects usable capacity after the BMS reserves its buffer.
Shear powers on but blade stalls under load
If the blade stalls when cutting thicker grass but spins freely in air, the battery is likely voltage-sagging under load — a common sign of a degraded or deeply discharged Ni-MH pack. The GS500's motor draws a sharp current spike at blade contact, and a weak pack can't sustain the voltage needed to push through. Fit the new pack, run a full conditioning cycle, and confirm the charger is rated for Ni-MH — using an incompatible charger will prevent proper cell formation and the stalling will return.