About this replacement
Dell Latitude 5580 / Precision 15 3520 — 11.4V Li-Polymer Replacement Battery (NY5PG)
This 11.4V, 7500mAh (85.5Wh) Li-Polymer battery replaces the original cell in the Dell Latitude 5580, Latitude 5591, Precision 15 3520, and Precision 3520. It matches the OEM voltage rail, connector, and BMS communication protocol used across these models. If the original cell has degraded or no longer holds a usable charge, this is the direct swap.
- Latitude 5580 / Precision 3520 platform compatibility: These models share the same battery bay dimensions, 11.4V three-cell architecture, and SMBUS handshake protocol. Part numbers NY5PG, VG93N, and WFWKK are cross-compatible across this platform because Dell used a unified power board spec across the 5580 and Precision 3520 lines.
- Bench tested on actual hardware: We ran this cell on a Latitude 5580 chassis and confirmed SMBUS communication, BMS charge acceptance from 0% to 100%, and correct Wh reporting in Dell Power Manager without error flags.
- BIOS battery learn cycle after install: After fitting this cell, 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 on Dell Latitude hardware.
BIOS reporting poor battery health immediately after replacing the Latitude 5580 cell
The Dell BIOS reads health data stored in the battery's EEPROM, not from real-time cell measurements. When a new cell is installed, the EEPROM data does not match the BIOS's learned profile from the old cell, so it flags the battery as degraded or unknown. This is a calibration mismatch, not a fault with the replacement cell. Running one full discharge-to-hibernate then a full uninterrupted charge resets the learn cycle and clears the warning.
Latitude 5580 shutting down suddenly at 20–30% battery shown
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The gauge predicts a higher remaining capacity than the cell can sustain under combined CPU and display load, so the voltage drops below the BMS cutoff threshold before the displayed percentage reaches zero. The laptop shuts down to protect the cell — it is not a faulty battery. Run two to three full charge and discharge cycles and the fuel gauge will remap its estimates to match the new cell's actual characteristics, typically stabilising around 11.1V at the low end.