About this replacement
Dell Inspiron 14V / M4010 Series — 11.1V Li-ion Replacement Battery (W4FYY)
This is an 11.1V, 4400mAh (48.84Wh) Li-ion replacement battery for the Dell Inspiron 14V, 14VR, 14R-346, and M4010 series laptops. It replaces OEM part numbers W4FYY, X3X3X, 0M4RNN, 0KCFPM, 312-1231, FMHC10, KG9KY, and TKV2V. The connector pinout and BMS communication protocol match the original Dell battery bay.
- Inspiron 14V and M4010 platform fit: These models share the same 11.1V battery bay, connector orientation, and SMBus BMS handshake. One cell covers all variants in this lineup without adapter or modification.
- Bench tested on actual hardware: We ran this cell on an Inspiron M4010 and monitored the SMBus data exchange. The BMS reported state-of-charge correctly within two charge cycles, and the protection circuit tripped at the expected 12.6V full-charge threshold.
- First-cycle calibration after install: After fitting this battery, run one full discharge down to hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.
BIOS reporting battery health as poor immediately after replacement
The Dell BIOS reads cycle count, design capacity, and health state from the battery's EEPROM. A new third-party cell ships with default EEPROM values that don't match what the BIOS expects from a Dell-coded pack. This triggers a "consider replacing your battery" warning even on a brand-new cell. Run two full discharge-to-charge cycles and the fuel gauge IC recalibrates against actual cell chemistry — the warning clears in most cases without any firmware change.
Inspiron 14V shutting down at 20–30% charge remaining
This is a voltage cliff failure, not a capacity or calibration issue. Under combined CPU and display load, the cells can't sustain voltage above the BIOS cutoff threshold, so the system shuts off before the fuel gauge reaches zero. Check the battery voltage under load with HWMonitor — if it drops below 10.5V while the gauge still shows 25%, the cell pack is experiencing excessive voltage sag. A full calibration cycle first; if sag persists past 11.0V under load, the replacement cell is the correct fix.