National EY9086 9.6V Ni-MH Cordless Drill Replacement Battery

National EZ6181 / EZ6481 Series — 9.6V Ni-MH Replacement Battery (EY9086)

This is a 9.6V Ni-MH battery rated at 2100mAh (20.16Wh), built to replace OEM part numbers EY9086, EY9086B, EY9182, and EY9182B. It fits the National EZ6181, EZ6481, EZ6482, EZ6482HKH, and over a dozen other models in this cordless drill range. When your original pack no longer holds a charge, this restores full operational power to the tool.

• Multi-model fit across the EZ6000 platform: The EZ6181, EZ6481, and EZ6482 variants all share the same 9.6V rail, physical connector, and battery bay dimensions. One pack covers the full platform — no wiring or adapter changes needed.
• Bench tested on actual hardware: We cycled this pack through repeated trigger pulls on an EZ6481 and monitored the BMS response to motor-start inrush current. The cell bank recovered cleanly between draws and the BMS held its overcurrent threshold without nuisance trips.
• First-use break-in for Ni-MH cells: Run the drill at half load for the first two cycles before applying full torque. Ni-MH cells need a few charge-discharge passes to reach rated capacity — pushing maximum load immediately off the shelf shortens the usable cycle count.

BMS cutoff on motor-start inrush in the EZ6181 and EZ6481

Cordless drills in this voltage class draw a current spike the moment the trigger is pulled — the motor needs far more current to overcome static load than it does to keep spinning. On a cold or recently charged pack, that inrush spike can briefly exceed the BMS overcurrent threshold and cut the circuit before the motor gets moving. This is more common when cells are below 8.5V resting voltage. Let the pack sit on charge for a full cycle and confirm resting voltage is above 9.0V before heavy drilling.

Tool bogs and slows under sustained load mid-job

If the drill slows noticeably when driving screws into hard timber or boring large holes, the most likely cause is voltage sag — the cells can't maintain rail voltage under sustained high-current draw. Check the battery contact rails on both the pack and the tool for corrosion or debris; even minor resistance at the contact point amplifies sag. Clean the contacts with isopropyl alcohol and retest. If sag persists after cleaning, measure pack voltage under load — anything dropping below 8.0V under moderate draw indicates cell degradation.