AEG BS 12 G Replacement Battery 12V 2100mAh B1215R

AEG BS 12 G / BSB 12 G Series — 12V Ni-MH Replacement Battery (B1215R)

This is a 12V, 2100mAh Ni-MH replacement battery for the AEG BS 12 G and related 12V cordless drill platform. It fits the BS 12 G, BS 12X, BSB 12 G, BSB 12 STX, and more than a dozen additional AEG 12V models sharing the same battery slot geometry and contact layout. OEM part numbers covered include B1215R, B1220R, M1230R, and 0700 980 320.

• 12V AEG drill platform fit: The BS 12 G, BSB 12 G, and BSB 12 STX all run the same 12V battery rail with an identical slide-in connector and contact pin spacing. AEG kept this footprint consistent across the range, so one battery covers the full group without adapter plates or pin modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the BS 12 G platform. The BMS held charge acceptance normally, current draw on the motor-start inrush stayed within cutoff thresholds, and cell temperature under sustained load remained within the Ni-MH operating window.
• Ni-MH first-cycle conditioning: On first use, run the drill at half load for two cycles before full-torque applications. This lets the BMS profile the motor inrush current draw and calibrate its overcurrent protection thresholds before you push the pack hard.

BMS overcurrent trip on motor-start inrush in the BS 12 G

When you pull the trigger on a stalled or heavily loaded bit, the motor draws a short inrush spike well above its running current. On a new or recently stored Ni-MH pack, the BMS may not yet have a current profile for this drill's motor and can trip the overcurrent protection prematurely. Running two light-load cycles first gives the BMS enough data points to set the correct trip threshold. After conditioning, the pack handles the inrush without shutting down mid-fastening.

Charger not recognising the pack after extended storage

Ni-MH cells that have sat unused will self-discharge over time. If the pack voltage drops below the charger's acceptance threshold — typically around 10.5V for a 12V Ni-MH pack — the charger won't initiate a full charge cycle and may show no activity or a fault indicator. To recover the pack, use a charger that supports a trickle or recovery mode, which applies a low current to bring the cell voltage back above the acceptance floor. Once the pack reads above threshold, the normal charge cycle will start and the pack will accept a full charge.