Bosch 36V Cordless Drill Replacement Battery BAT836 3000mAh

Bosch 11536C Series — 36V Li-ion Replacement Battery (BAT836)

This is a 36V Li-ion replacement battery rated at 3000mAh (108Wh). It fits the Bosch 11536C, 11536C-1, 11536C-2, 11536VSR, and over 20 additional Bosch cordless power tool models. It replaces OEM part numbers BAT836, BAT840, BAT810, BAT838, and related Bosch part numbers in this voltage family.

• 11536C platform compatibility: These Bosch 36V tools share the same slide-rail connector geometry, cell-voltage range, and BMS communication protocol. The charger handshakes with the pack over the same data line, so the charge cycle initialises the same way as with the original pack.
• Bench tested on actual hardware: We ran this pack on a 36V Bosch drill under repeated motor-start cycles. The BMS held overcurrent thresholds correctly at trigger pull and balanced cells within the expected window across a full discharge-to-charge sequence.
• Motor inrush break-in on first use: On first use, run the tool at half load for two cycles before full-torque applications. This lets the BMS log the motor inrush current draw and set its overcurrent protection thresholds accurately for your specific tool before you put it under heavy load.

BMS cutoff on the 11536C motor-start inrush surge

Pulling the trigger on a 36V rotary hammer sends a brief inrush spike that can be three to five times the steady-state draw. If the BMS has not yet profiled the motor, it may read that spike as a fault and cut the pack. The protection circuit resets once the trigger is released, but the underlying threshold stays conservative until the BMS logs enough cycles to widen its window. Running two half-load cycles first resolves most trigger-pull cutouts before they become a pattern.

Charger blinks red and never starts the charge cycle

After extended storage, individual cells can drop below the charger's acceptance threshold — typically around 2.5V per cell. The Bosch charger reads this as a fault rather than a dischargeable pack, so it refuses to begin the charge cycle and signals that with a red blink. Some Bosch chargers include a recovery or "wake-up" mode that applies a low-current trickle to bring cells back above threshold before switching to normal charge. If yours does not, connect the pack, wait 60 seconds, then disconnect and reconnect — this forces the charger to re-poll the pack voltage and sometimes clears the fault if cells have recovered marginally above 2.5V per cell.