Bosch BAT618 18V Angle Grinder Replacement Battery 3000mAh

Bosch GWS 18 V-LI Series 18V Li-ion Replacement Battery (BAT618)

This 18V 3000mAh (54Wh) Li-ion battery replaces Bosch part numbers BAT618, BAT609, BAT610G, BAT622, and several 2 607 336 series packs. It fits the GWS 18 V-LI angle grinder along with the GSR 18-2-LI, GSR 18 VE-2-LI, GSR 18 V-LI, and over 30 additional 18V Bosch tools on the same platform.

• Bosch 18V platform compatibility: All listed models share the same 18V rail voltage, slide-in connector, and BMS communication protocol. The cell configuration and terminal layout are identical across the BAT609 through BAT622 family, which is why one pack covers this many tools without modification.
• Bench tested on actual hardware: We ran this pack on a GWS 18 V-LI under cyclic grinding load. The BMS held the discharge rail steady through repeated inrush spikes and triggered a clean overcurrent cutoff only at the correct threshold no false trips during normal trigger pulls.
• Break-in procedure for angle grinder use: On first use, run the grinder at partial load for two full discharge-charge cycles before sustained cutting or grinding. This allows the BMS to calibrate its overcurrent threshold against the motor’s actual inrush profile, reducing nuisance cutoffs during heavy disc work.

BMS cutoff on motor-start inrush surge in the GWS 18 V-LI

When you pull the trigger on an angle grinder, the motor draws a brief but sharp inrush current often 3 to 5 times the steady running draw. A new or storage-conditioned pack can read this spike as an overcurrent fault and cut out immediately. The BMS needs two or three real-load cycles to distinguish a normal motor start from a genuine fault condition. If cutouts persist past the break-in cycles, check the slide-in terminal contacts for corrosion or debris raising contact resistance.

Grinder bogs and loses torque mid-cut without fully stopping

This is voltage sag the cell rail drops under sustained disc load, and the tool slows instead of cutting out cleanly. It usually points to elevated internal resistance in the cells, which can happen after deep discharge or long storage. First, check that the battery slides fully into the tool and the terminals seat without play a loose fit adds rail resistance and worsens sag. If seating is solid, charge the pack to full, run a complete discharge under moderate load, and recharge; if sag persists after two cycles, cell resistance has climbed past recovery and the pack needs replacement.