About this replacement
AEG BS 18C / BKS 18 Series — 18V Li-ion Replacement Battery (L1830R)
This is an 18V 3000mAh Li-ion battery that fits the AEG BS 18C, BS 18G, BKS 18, BFL 18, and eleven additional AEG 18V cordless tools. It replaces OEM part numbers L1815R and L1830R. Voltage and cell chemistry match the original battery pack specification exactly.
- BS 18C, BS 18G, BKS 18, BFL 18 compatibility: These models share the same 18V slide-rail connector, BMS communication protocol, and charge management handshake. Any pack that meets the voltage rail and connector spec will operate across the full lineup without modification.
- Bench tested on actual hardware: We ran this pack through trigger-pull cycles on a BS 18C and monitored the BMS response to motor-start inrush current. The overcurrent protection threshold held correctly, and the pack did not trip or latch off during repeated cold-start pulls.
- First-use load conditioning: On first use, run the drill at half load — light drilling, no high-torque fastening — for the first two full charge cycles. This allows the BMS to profile the motor's inrush draw before it locks in its overcurrent protection thresholds for your specific tool.
BMS overcurrent trip on motor-start inrush in the BS 18C
When you pull the trigger on a cordless drill, the motor draws a spike of current before it reaches running speed — this inrush can be three to five times the steady-state draw. A new pack with a freshly calibrated BMS sometimes reads that spike as a fault and cuts power instantly. The fix is graduated load cycling during the first two uses, so the BMS records the normal inrush curve for your motor. After two cycles, the protection thresholds stabilise and nuisance trips stop.
Pack voltage drops below charger acceptance threshold after storage
Li-ion cells self-discharge during storage, and if the pack sits long enough, cell voltage can fall below the minimum the charger will accept — typically under 2.5V per cell. The charger blinks red or does nothing because it will not push charge into a pack it cannot verify as safe. To recover the pack, place it in the charger and leave it connected for up to 30 minutes — most AEG chargers run a trickle pre-charge routine that raises cell voltage to the acceptance threshold before switching to normal charge. If the charger still shows a fault after 30 minutes, check each cell group with a multimeter and confirm no individual cell has dropped below 2.0V.