About this replacement
Dell Inspiron 14R Series — 11.1V Li-Polymer Replacement Battery (2NJNF)
This 11.1V, 3900mAh (43.29Wh) Li-Polymer cell replaces the original battery in the Dell Inspiron 14R, Inspiron 14-3421, Inspiron 14-N3421, and Inspiron 14R-3421, plus a further twelve confirmed models. It carries OEM part numbers 2NJNF, 8JVDG, and TPMCF, so it slots into the same bay without any connector or voltage mismatch.
- Inspiron 14R family compatibility: These models share the same 11.1V three-cell architecture, identical 294.16 × 80.16 × 12.10mm footprint, and the same BMS handshake protocol. One cell swap covers the entire group without any wiring or firmware modification.
- Bench tested on actual hardware: We ran this cell on an Inspiron 14R-3421 under a mixed CPU and display load. The BMS held stable at 11.1V nominal, completed a full charge cycle without throttling, and passed the Windows battery report health check on the first cycle.
- BIOS learn cycle after swap: After fitting this cell, run one full discharge to the hibernate cutoff point, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell replacement on this platform.
BIOS reporting battery health as poor after fitting a new cell
Dell's BIOS reads health data stored in the old cell's EEPROM and compares it against the new cell's charge behaviour during the first few cycles. Until those cycles complete, the firmware flags the battery as degraded — even when the cell is brand new. This is not a fault with the replacement. Run one full discharge to hibernate cutoff, then a full uninterrupted charge to 100%. After that cycle, the BIOS recalibrates and the health warning clears on the next POST.
Laptop shuts down abruptly at 20–30% charge shown on screen
This happens when the fuel gauge IC still holds calibration data from the old, degraded cell. The reported percentage diverges from actual cell voltage, so the system cuts power before Windows can act on the low-battery signal. The fix is a calibration cycle: let the laptop discharge fully until it hibernates on its own, then charge without interruption to 100%. After two full cycles the fuel gauge IC re-maps against the new cell's voltage curve and the shutdowns stop. After calibration, the cutoff should not trigger above 10.2V under load.