HP Dragonfly 13.5 G3 Replacement Battery 7.72V 5650mAh

HP Dragonfly 13.5 inch G3/G4 — 7.72V Li-Polymer Replacement Battery (HSTNN-OB2L / SS04XL)

This is a 7.72V, 5650mAh (43.62Wh) lithium-polymer battery for the HP Dragonfly 13.5 inch G3 (Starfox) and G4 (Sandwalker) ultrabooks. It replaces OEM part numbers HSTNN-OB2L, SS04XL, M64309-271, M73476-006, and TPN-DB0N. If your Dragonfly no longer holds a charge away from the outlet, this cell restores that capability.

• G3 and G4 Dragonfly compatibility: Both the Starfox (G3) and Sandwalker (G4) platforms share the same 7.72V voltage rail, physical form factor, and BMS communication protocol — which is why one cell covers both generations. The connector pinout and SMBus handshake are identical across these models.
• Bench tested on actual hardware: We ran this cell on a Dragonfly G3 unit and cycled it through full charge and discharge. The BMS accepted the cell without fault codes, the SMBus reported capacity correctly after two cycles, and the charge controller held the 7.72V rail steady under combined CPU and display load.
• Post-install calibration on the Dragonfly: After fitting this cell, run a full discharge until the laptop hibernates, then charge uninterrupted to 100% without interruption. This forces the Dragonfly's BIOS battery learn cycle to reset against the new cell's EEPROM data and clears the false "poor health" warning that appears after every cell swap on this platform.

BIOS reporting battery health as poor after replacement on the Dragonfly G3

When you swap cells on the Dragonfly G3, the BIOS compares the new cell's EEPROM data against the charge history stored from the old battery. Because the records don't match, HP's battery health algorithm flags the new cell as degraded — even when it's factory fresh. This is a firmware behaviour, not a cell defect. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the BIOS learn cycle and rewrites the health baseline. After one or two full cycles, the reported health status corrects itself.

Dragonfly shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. In the first few cycles after a cell swap, the fuel gauge IC still uses learned data from the old, degraded battery — so it misreads the new cell's state of charge. When the displayed percentage shows 25% but the cell voltage has already dropped to roughly 6.8V under full CPU and display load, the system triggers an emergency shutdown. Run two full discharge-to-hibernate and full-charge cycles to let the IC recalibrate its curve against the new cell. After that, the percentage readout will track voltage accurately.