Makita BH1220 12V Ni-MH Replacement Battery 2200mAh

Makita BFH120F / BFL Series — 12V Ni-MH 2200mAh Replacement Battery (193346-2)

This is a 12V 2200mAh Ni-MH battery replacement for Makita cordless drills and drivers across the BFH and BFL series. It fits the BFH120F compact impact driver and BFL081F, BFL121F, BFL200F, and over 36 additional models sharing the same 12V platform. OEM cross-references include 193349-6, BH1220, BH1233, BH1233C, and related part numbers.

• BFH/BFL 12V platform compatibility: These models share a common 12V battery rail, connector footprint, and BMS handshake protocol. Swapping this pack across any model in the group requires no adapter — the cell count, terminal layout, and communication line match across the platform.
• Bench tested on actual hardware: We cycled this pack through full discharge and recharge sequences on the BFH120F and monitored the BMS under repeated motor-start inrush loads. The protection circuit held stable across trigger pulls without nuisance trips, and cell voltages balanced correctly through charge termination.
• First-use load conditioning: Run the tool at half load for two cycles before maximum torque applications. This lets the BMS profile the motor's inrush current draw and set overcurrent thresholds accurately before you're driving fasteners at full torque.

BMS overcurrent trip on motor-start inrush in 12V Ni-MH tools

When you pull the trigger on a compact impact driver, the motor draws a spike of current before it reaches running speed — often three to five times the steady-state draw. On a new or cold Ni-MH pack, internal resistance is slightly elevated, which makes that inrush spike look steeper to the BMS. If the protection circuit hasn't yet profiled the motor load, it can read the spike as a fault and cut the output. Running two break-in cycles at reduced load teaches the BMS where the legitimate inrush ceiling sits, so it stops tripping on normal trigger pulls.

Tool bogs under load after the pack shows full charge

Voltage sag under load is the most common cause of a sluggish drill that shows a full charge at rest. Ni-MH cells that have been shallow-cycled repeatedly lose capacity and sag harder under the current draw of driving screws or boring holes. Check the terminal contacts on the battery and tool — oxidised or dirty contacts add resistance and make sag worse. Clean the contacts with isopropyl alcohol, then run the pack through two full discharge-to-charge cycles to let the BMS recalibrate its state-of-charge readings against real cell capacity.