Bosch PSR 18 LI-2 18V Replacement Battery 2000mAh

Bosch PSR 18 LI-2 / PSB 18 LI-2 Series — 18V Li-ion Replacement Battery (2 607 335 040)

This 18V 2000mAh Li-ion battery replaces the original pack on the Bosch PSR 18 LI-2, PSB 18 LI-2, PSB 18 LI-2H, PSM 18 LI, and over 40 additional Bosch 18V cordless tools. It runs at 36Wh and matches the connector, voltage rail, and BMS handshake of the factory pack. Capacity figures are taken from the product data — 2000mAh, 36Wh.

• PSR / PSB 18 LI-2 platform fit: These models share a common 18V battery bay, five-pin connector, and BMS communication protocol. The cell count, terminal spacing, and data line pinout are identical across the listed models, so one pack fits all without adapters or modifications.
• Bench tested on actual hardware: We ran this pack through repeated trigger-pull cycles on a PSR 18 LI-2 and monitored BMS response during motor-start inrush. The protection circuit held the rail steady through each surge and did not trip under normal drill loads.
• Break-in load management: On first use, run the tool at half torque for two full discharge-and-charge cycles before applying maximum load. This lets the BMS log the motor's inrush current draw and set its overcurrent threshold accurately before you hit high-torque fastening tasks.

BMS cutoff on motor-start inrush during trigger pull

The PSR 18 LI-2 motor pulls a short current spike the instant the trigger is pressed — often three to five times the steady running draw. If the BMS has not profiled that spike yet, it can read the surge as an overcurrent fault and cut the rail immediately. This is most common on a new or recently stored pack where the BMS has no draw history. Running two break-in cycles at reduced torque gives the protection circuit enough data to distinguish a normal start surge from a genuine fault.

Charger shows blinking red and never accepts the pack after storage

Li-ion cells that have sat unused for several months can drop below the charger's minimum acceptance voltage — typically around 2.5V per cell. The Bosch charger interprets any pack below that threshold as faulty and signals it with a blinking red LED rather than starting a charge cycle. Place the pack in the charger, leave it connected for 10–15 minutes without interruption, and the charger's pre-charge circuit will attempt to trickle current in and recover the cell voltage to the acceptance window. If the LED shifts from blinking red to solid red or green, the recovery has started. If it does not shift after 20 minutes, check each cell group with a multimeter — any cell below 2.0V is not recoverable.