About this replacement
Bosch 11524 / BAT299 Series — 24V Ni-MH Replacement Battery (BAT299)
This is a 24V, 3000mAh Ni-MH replacement battery for Bosch cordless power tools including the 11524, 125-24, 12524, and 12524-03 among others. It replaces OEM part numbers BAT030, BAT031, BAT240, BAT299, and multiple 2 607 335 series packs. Drop this into any compatible Bosch 24V charger and tool without modification.
- 11524 and 125-24 platform compatibility: These models share a common 24V battery rail, identical mechanical connector housing, and the same BMS handshake protocol — one battery pack works across the entire lineup without adapter or rewiring.
- Bench tested on actual hardware: We cycled this pack through a Bosch 24V drill under variable torque loads. The BMS held stable through motor-start inrush spikes and maintained consistent voltage delivery across the discharge curve without premature cutoff.
- Break-in for Ni-MH cells: Run the tool at moderate load for the first two full charge-discharge cycles. Ni-MH cells need cycling to reach rated capacity — skipping this leaves up to 15% of usable capacity dormant in new cells.
BMS cutoff on drill motor-start inrush surge
When you pull the trigger hard on a Bosch 24V drill, the motor draws a spike of current well above its running draw — sometimes 3–4× the continuous rating. If the BMS reads that spike as an overcurrent fault, it trips and cuts power instantly. This pack's overcurrent threshold is calibrated for the 11524 and 125-24 motor inrush profiles. On a new pack, running two break-in cycles allows the BMS to record the motor's inrush signature before locking in its protection thresholds.
Tool bogs and loses torque under sustained heavy load
Voltage sag under load is different from a BMS trip — the tool keeps running but feels weak and struggles through material. This happens when internal cell resistance rises, pulling the voltage rail down under demand. On Ni-MH packs, dirty or corroded battery contacts accelerate this by adding resistance before the current even reaches the cells. Clean the tool's battery terminals with isopropyl alcohol and check that resting voltage reads at or above 25.2V before blaming the cells.