About this replacement
Dell Latitude E5440 / E5540 — 11.1V Li-ion Replacement Battery (VJXMC)
This is an 11.1V, 4400mAh (48.84Wh) Li-ion battery for the Dell Latitude E5440 and E5540 series laptops. It also covers the Latitude 14 5000-E5440 and Latitude 15 5000-E5540. Cross-referenced OEM part numbers include VJXMC, VVONF, N5YH9, and 451-BBID, among others.
- E5440 and E5540 shared platform: Both the E5440 and E5540 use the same 11.1V three-cell battery bay, connector pinout, and BMS handshake protocol. A single replacement cell covers both chassis without modification.
- Bench tested on actual hardware: We ran this cell on an E5440 and monitored BMS communication across the SMBus. The pack reported capacity, cycle count, and charge state correctly. BIOS battery health check passed without flags on both test units.
- First-cycle reset after install: After fitting this cell, run the laptop down to hibernate cutoff under normal load — screen on, a few background tasks — then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on the first boot after any cell swap.
BIOS reporting battery health as poor immediately after replacement
Dell's BIOS reads health data from the EEPROM embedded in the battery pack. When a new cell arrives, that EEPROM contains factory default values that don't match any learned charge history, so the BIOS flags it as degraded. This is not a fault with the replacement cell. Run one full discharge-to-hibernate followed by an uninterrupted charge to 100% — this writes a fresh charge profile to the EEPROM and clears the warning. After two or three full cycles, the health indicator should read normal.
Laptop shutting down at 20–30% shown on the fuel gauge
This happens when the fuel gauge IC hasn't yet calibrated against the new cell's actual voltage curve. The IC still uses discharge curve data from the old, degraded cell, so it misreads the remaining capacity. Under full CPU and display load, voltage drops sharply at the real low-capacity threshold before the gauge catches up. Run two or three complete discharge-to-hibernate cycles without interruption. By the third cycle, the fuel gauge recalibrates and the shutdown point aligns with the actual 10–11V low-cell cutoff.