About this replacement
Bosch 11536C Series — 36V Li-ion Replacement Battery (BAT836)
This is a 36V, 4000mAh Li-ion replacement battery for the Bosch 11536C, 11536C-1, 11536C-2, 11536VSR, and compatible 36V Bosch power tool platforms. It replaces OEM part numbers BAT836, BAT840, BAT810, BAT838, and several 2 607 336 series packs. The cell configuration and BMS communicate with Bosch's 36V charger protocol directly.
- 11536C platform compatibility: The 11536C rotary hammer and its variants run a 36V rail with a 10-cell Li-ion arrangement. These models share the same battery bay geometry, contact layout, and BMS handshake signal — which is why BAT836, BAT840, and BAT838 are interchangeable across the lineup.
- Bench tested on actual hardware: We cycled this pack on a 36V Bosch platform under rotary hammer load conditions. The BMS held the overcurrent threshold through repeated high-inrush trigger pulls and balanced cell voltages correctly across charge and discharge cycles.
- Motor-start conditioning on first use: On first use, run the rotary hammer at half load for two cycles before full chisel or drill applications. This lets the BMS profile the motor's inrush current spike and set its overcurrent protection threshold accurately before you push the tool hard.
BMS cutoff on rotary hammer motor-start inrush surge
The 11536C draws a significant current spike the instant the trigger is pulled — this inrush can briefly exceed 30A on a stalled or cold motor. If the BMS hasn't profiled the tool's inrush pattern, it may read the spike as a fault and cut power. This is more common with a freshly installed or storage-discharged pack. Run two partial-load cycles first so the BMS establishes an accurate overcurrent baseline before heavy applications.
Charger not recognising the pack after extended storage
Li-ion cells that drop below approximately 2.5V per cell during storage fall outside the voltage window most Bosch 36V chargers will accept for a standard charge cycle. The charger may blink an error or show no response at all. Some Bosch chargers include a recovery or trickle-wake mode — leave the pack seated for 5–10 minutes to allow the charger to attempt cell recovery. If cell voltage is at or above 2.5V per cell across the pack, the charger should accept it and begin a normal charge.