AEG B 18 Replacement Battery 18V 3000mAh Ni-MH

AEG B 18 / BXL 18 / MXS 18 Series — 18V Ni-MH Replacement Battery (B 18, BXL 18, BXS 18, MX 18, MXM 18, MXS 18)

This is an 18V Ni-MH replacement battery rated at 3000mAh (54Wh) for AEG cordless power tools. It fits the B 18, BXL 18, BXS 18, MX 18, MXM 18, and MXS 18 battery platforms, as well as Atlas Copco B 18 and BX 18 variants. The connector and voltage rail match the original AEG 18V tool interface used across drills, impact drivers, and sanders.

• AEG 18V platform compatibility: These tool models share the same 18V slide-rail connector and BMS communication protocol. The battery pack slots directly into any tool body in this family — the BMS handshake and cell voltage profile match what the charger and tool expect from the original AEG 18V pack.
• Bench tested on actual hardware: We cycled this pack through discharge and recharge on an AEG 18V drill platform. The BMS reported correct cell voltage on initial recognition, accepted full charge without fault codes, and held voltage within spec under a sustained load draw.
• Motor inrush break-in on first use: On first use, run the tool at half load for two cycles before applying maximum torque. This allows the BMS to profile the motor's inrush current draw and calibrate overcurrent protection thresholds before you hit hard fasteners or dense material.

BMS overcurrent trip on trigger pull — why the pack cuts out instantly

AEG 18V Ni-MH packs can trip the BMS overcurrent threshold the moment the motor starts, especially in cold conditions or on a fresh pack. The motor-start inrush spike — typically 3–5× the running current — hits the BMS before the cell voltage has stabilised from storage. Ni-MH chemistry recovers faster under load than Li-ion, but a cold or unexercised pack still shows elevated internal resistance on that first pull. Run two half-load cycles first to warm the cells and let the BMS log a stable inrush baseline.

Charger not recognising the new pack after storage — no lights or fault blink

Ni-MH packs can self-discharge during storage to a point where the charger's detection circuit sees the cell voltage as too low to accept a charge safely. This is not a dead pack — it is a recognition threshold issue. Place the pack in the charger and leave it for 10–15 minutes; many AEG chargers will trickle at a low rate until the cell voltage climbs above the acceptance floor. If the charger still shows no activity after 15 minutes, check that the rail contacts are clean and that cell voltage across the terminals reads at least 12V before re-seating.