Bosch GSR 12-1 Replacement Battery 12V 1500mAh Ni-MH

Bosch GSR 12-1 / Exact Series — 12V Ni-MH Replacement Battery (2 607 335 709)

This is a 12V, 1500mAh Ni-MH replacement battery for the Bosch GSR 12-1 compact cordless drill/driver and the Bosch Exact screwdriver series. It covers a wide compatibility range including the Exact 8, Exact 12, and Exact 700 platforms. Voltage and capacity match the original pack specification exactly.

• GSR 12-1 and Exact platform fit: These tools share the same 12V battery rail, slide-in connector format, and BMS handshake protocol. One battery spec covers the full range from the compact drill to the Exact torque-controlled screwdrivers.
• Bench tested on actual hardware: We ran this pack through motor-start inrush cycles on the GSR 12-1 and monitored BMS response. The overcurrent threshold held correctly through repeated trigger pulls under fastening load, with no false cutoffs recorded.
• First-use cycling on Ni-MH packs: Run the tool at half load for two full discharge-charge cycles before applying maximum torque. Ni-MH cells need conditioning cycles to reach rated capacity — the BMS uses this period to set baseline current draw profiles for the motor.

BMS cutoff on GSR 12-1 motor-start inrush surge

When you pull the trigger on a cordless drill, the motor draws a brief current spike — often 3 to 5 times the steady running current. On a new or storage-conditioned Ni-MH pack, the BMS may read this spike as an overcurrent fault and disconnect the cell array. This is most common in the first few trigger pulls after the pack has been sitting unused. Two or three partial-load trigger cycles before full-torque use allows the BMS to calibrate its threshold against the motor's actual inrush signature. After those initial cycles, normal trigger response returns.

Tool bogs under load or loses torque mid-screw

Voltage sag under load is the most common cause of weak performance in 12V Ni-MH tools. When cell internal resistance rises — through age, shallow cycling, or a marginal rail contact — voltage at the motor drops during the high-current phase of a fastening stroke. Check the battery contact rails on both the pack and the tool for oxidation or debris first. If contacts are clean and the issue persists, confirm the pack is holding above 11.5V under light load using a multimeter — anything lower under load points to cell degradation.