Panasonic EY9086 9.6V Ni-MH Replacement Battery 3300mAh

Panasonic EY6181CQK Series — 9.6V Ni-MH Replacement Battery (EY9086)

This is a 9.6V 3300mAh Ni-MH replacement battery for the Panasonic EY6181CQK cordless drill/driver and related models in that series. It replaces OEM part numbers EY9086, EY9086B, EY9182, EY9182B, EZ9086, EZ9182, EZ9183, EZ9186, and EZ9187. Voltage and capacity match the original pack specification.

• EY6181 series compatibility: The EY6181CQK, EY6181CRKW, EY6181EQKW, and EY6188CRKW all share the same 9.6V battery rail and connector format. The BMS handshake protocol and cell count are identical across these models, so one pack fits the full range without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a Panasonic 9.6V platform. The BMS responded correctly to charge termination signals and held voltage within spec across multiple torque cycles at the drill spindle.
• Motor inrush break-in on first use: On first use, run the drill at half load for two cycles before applying maximum torque. This lets the BMS establish accurate overcurrent thresholds against the motor's inrush current profile before you stress the pack under full drilling load.

BMS cutoff on EY6181 motor-start inrush surge

When you pull the trigger on a Ni-MH drill pack, the motor draws a spike of current well above its steady running draw. On a cold or freshly installed pack, the BMS may read that spike as an overcurrent event and cut power before the motor reaches speed. This is more common in the first few trigger pulls on a new or storage-rested pack. The fix is a controlled break-in: two or three light-load cycles let the BMS log real inrush data and set its trip threshold above the normal motor-start spike. After break-in, the cutout behaviour typically stops.

Drill bogs under load and loses torque mid-hole

If the drill starts strong but loses speed when the bit bites into material, the cause is usually voltage sag — the cell voltage drops under sustained current draw faster than it should. On Ni-MH packs this is often a contact resistance issue at the battery terminal rather than cell failure. Clean the pack contacts and tool contacts with isopropyl alcohol, then check the voltage under load with a multimeter. A healthy pack at 9.6V nominal should hold above 8.4V under moderate drilling load; consistent drops below that point to cell degradation.