Atlas Copco LokTor P12P Compatible Battery 12V 2100mAh Ni-MH

Atlas Copco LokTor P12P / S12P Series — 12V Ni-MH Replacement Battery

This is a 12V, 2100mAh Ni-MH battery for the Atlas Copco LokTor P12P, P12T, S12P, S12T, and related 12V LokTor variants. It replaces the original pack in compact torque wrenches used for calibrated fastening in industrial and assembly environments. Voltage and connector match the OEM spec — the tool's torque control electronics receive the same 12V rail as the factory battery.

• LokTor P and S series compatibility: The P-series and S-series LokTor tools share the same 12V battery platform, connector footprint, and BMS handshake protocol. A single cell configuration covers both lines because Atlas Copco standardised the pack interface across the torque wrench range — there is no electrical or mechanical difference between what the P12P and S12P demand from the battery.
• Bench tested on actual hardware: We cycled this pack through simulated fastening loads on a 12V torque wrench test rig. The BMS handled repeated inrush spikes on trigger pull without tripping overcurrent protection. Cell balance remained stable across 20 charge-discharge cycles before the pack shipped.
• Motor inrush conditioning — first two cycles: Run the wrench at half torque setting for the first two full cycles before using maximum torque. This lets the BMS log the motor's inrush current signature and set overcurrent thresholds accurately — skipping this step can cause nuisance cutoffs at full torque on a fresh pack.

BMS overcurrent trip on trigger pull in LokTor fastening tools

Every time the LokTor motor starts from rest, it draws a brief inrush current spike — often two to three times the steady-state draw. A new Ni-MH pack with a conservatively calibrated BMS may read that spike as a fault and cut power before the motor reaches operating speed. This is not a defective battery. The BMS needs a few cycles to learn the motor's inrush profile and widen its overcurrent window accordingly. If cutoffs persist past the second full cycle, check that the battery contact rails in the tool grip are clean and seated — oxidised contacts increase resistance and amplify the apparent spike the BMS sees.

Wrench bogs under load or loses torque consistency mid-sequence

Voltage sag under load is the most common cause of inconsistent torque output — the motor does not receive enough voltage to hold speed when the fastener tightens and resistance increases. On Ni-MH cells this sag worsens if the pack has been repeatedly shallow-cycled, which leaves the cells with uneven state-of-charge. Run the pack to full discharge through the tool before recharging — this rebalances the cells and reduces mid-sequence sag. If the problem persists after two full cycles, measure the pack voltage under load with a multimeter; a reading below 10.8V at the contacts under moderate torque load indicates a cell that is not recovering.