About this replacement
Dell Alienware 13 R2 — 15.2V Li-ion Replacement Battery (N1WM4)
This is a 15.2V, 3100mAh (47.12Wh) Li-ion battery for the Dell Alienware 13 R2 gaming laptop. It fits the full AW13R2 lineup, including the AW13R2-1678SLV and ALW13ER-1708S variants. It replaces OEM part numbers N1WM4, 2VMGK, 3V806, 257V0, and related P56G board revisions.
- Alienware 13 R2 platform compatibility: All AW13R2 variants share the same P56G motherboard platform, 15.2V four-cell voltage rail, and BMS handshake protocol. One battery covers every SKU in the R2 generation — the connector, pinout, and charge controller communication are identical across the lineup.
- Bench tested on actual hardware: We ran this cell on a P56G001 board and confirmed the BMS negotiated charge current correctly without triggering the Dell ExpressCharge fault flag. The protection circuit responded to load spikes from the GTX 960M GPU draw without dropping the bus.
- Post-install calibration on the Alienware 13 R2: After fitting this battery, run one full discharge to the hibernate cutoff, then charge uninterrupted to 100% without using the laptop. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor after installing a new cell
The Alienware 13 R2 BIOS stores charge history and wear data in the EEPROM of the original battery pack. When a new cell goes in, that EEPROM data is gone — the BIOS reads the absence of accumulated cycle data as a fault condition, not a fresh start. This triggers the "Battery health is poor" warning in the Dell BIOS health screen even on a brand-new cell. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to rewrite the battery learn data against the new cell and clears the warning. If the warning persists after two full calibration cycles, check BIOS version — some early R2 firmware versions require an update before they recognise third-party cell EEPROM correctly.
Laptop shuts down at 20–30% shown on the Windows fuel gauge
This is a voltage cliff issue, not a fuel gauge bug. Under combined CPU and display load, the cell voltage drops sharply at around 20–30% state of charge — faster than the fuel gauge IC can track. The system hits the low-voltage cutoff threshold before the displayed percentage reaches zero, forcing an immediate shutdown. The fuel gauge IC on the P56G board needs two to three full calibration cycles against the new cell before its discharge curve model is accurate enough to predict the cliff. After calibration, the shutdown point and the displayed percentage will align. Confirm by checking battery voltage in HWiNFO — a healthy cell at 25% shown should read no lower than 14.6V under full GPU load.