About this replacement
HP ProBook 5220m — 14.8V Li-ion Replacement Battery (595669-721)
This is a 14.8V, 2200mAh Li-ion battery for the HP ProBook 5220m notebook. It replaces OEM part numbers 595669-721, 595669-741, BQ349AA, BQ351AA, FE04, FE06, and related HSTNN variants. Capacity matches the factory 32.56Wh specification listed in the product data.
- ProBook 5220m compatibility: All OEM part numbers listed above share the same 14.8V rail, four-cell configuration, and BMS handshake protocol. The connector pinout and EEPROM communication format are identical across the FE04 and FE06 variants, so the same cell fits both.
- Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on a ProBook 5220m unit. The BMS authenticated without error, charge termination triggered correctly at capacity ceiling, and the system did not flag an unknown device alert on first boot.
- First-cycle calibration on the ProBook 5220m: After installing, run one full discharge to hibernate cutoff, then charge uninterrupted to 100%. This forces the ProBook's fuel gauge IC to re-learn the new cell's actual capacity curve and clears the inaccurate health warning that appears in HP Support Assistant after a cell swap.
Why the ProBook 5220m shuts down at 20–30% remaining after a battery swap
The ProBook 5220m uses a fuel gauge IC that stores cell capacity data from the previous battery in non-volatile memory. After a swap, that stored data no longer matches the new cell's actual voltage-versus-capacity curve. Under full CPU and display load, the system hits a voltage cliff the old data did not predict, and the BIOS triggers an emergency shutdown before the displayed percentage reaches zero. Running two to three full calibration cycles — discharge to hibernate cutoff, full uninterrupted charge — rewrites the fuel gauge map to match the new cell and eliminates the premature cutoff.
HP BIOS reporting wrong Wh rating after replacement cell installed
The Wh figure shown in BIOS and HP Support Assistant is read from the battery's EEPROM, not measured in real time. On a new replacement cell, the EEPROM value reflects the rated chemistry spec, which can differ slightly from what the original OEM unit reported. This is a data mismatch, not a capacity fault. To confirm the cell is functioning correctly, check that pack voltage reads between 16.4V and 16.8V at full charge using a multimeter on the connector pins — if it does, the cell is healthy and the Wh discrepancy is cosmetic.