About this replacement
Dell Latitude E7240 / E7250 — 11.1V Li-Polymer Replacement Battery (451-BBFW)
This is an 11.1V, 2600mAh (28.86Wh) lithium-polymer replacement battery for the Dell Latitude E7240, Latitude E7250, and Latitude 12-7000 series ultrabooks. It replaces OEM part numbers 451-BBFW, 451-BBFX, GVD76, HJ8KP, NCVF0, and several others listed in Dell's own service manual interchangeability table. The slim 9.42mm profile matches the original cell dimensions, so fitment inside the chassis is direct.
- E7240 and E7250 share this battery: Both platforms run the same 11.1V three-cell bus, use the same SMBus connector pinout, and communicate with the same Dell BMS handshake protocol. Dell's own service documentation lists the part numbers above as valid across both chassis revisions.
- Bench tested on actual hardware: We cycled this cell on an E7240 unit under load — display at full brightness, CPU running a sustained encode task. The BMS reported state-of-charge correctly from the first cycle, and the protection circuit tripped at the correct low-voltage cutoff without requiring any manual reset.
- BIOS learn cycle after swap: After installing this cell, run the laptop down to hibernate-cutoff under normal use, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle. Skipping this step causes Windows battery health to report inaccurately for several days after the swap.
Why the E7240 BIOS flags a new battery as "poor health" immediately after install
The E7240 stores battery health data in EEPROM on the original cell. When a new cell goes in, the BIOS reads its stored cycle count and full-charge capacity data — both reset to defaults — and interprets that mismatch as a degraded battery. This is a firmware behaviour, not a fault with the replacement cell. Running one complete discharge-to-hibernate followed by a full uninterrupted charge forces the Dell fuel gauge IC to write fresh calibration data to the new cell's EEPROM. After two to three cycles, the health status normalises.
Laptop shuts down at 20–30% charge shown on the gauge
This symptom points to a voltage cliff under combined CPU and display load — the cell voltage drops faster than the fuel gauge IC can track when power draw spikes. The gauge still shows 20–30% because it is reading resting voltage between samples, but the cell cannot sustain the voltage rail under sudden full-load demand. On first install, run the BIOS battery diagnostics (F12 at boot → Diagnostics → Battery) to confirm the cell is communicating correctly. If diagnostics pass and the shutdown persists after two full calibration cycles, check that the BIOS power management profile is not set to "Ultra Performance," which raises the CPU TDP ceiling and increases peak draw beyond what a 2600mAh cell can sustain at low state-of-charge.