About this replacement
HP EliteBook Folio 1020 Series — 7.6V Li-Polymer Replacement Battery (BR04XL)
This is a 7.6V, 4700mAh (35.72Wh) Li-Polymer replacement battery for the HP EliteBook Folio 1020 and Folio 1020 G1 series ultrabooks. It replaces OEM part numbers BR04XL, 760505-005, 765605-005, HSTNN-DB6M, HSTNN-I26C, and HSTNN-I28C. The flat Li-Polymer cell matches the original 5.60mm slim-profile slot inside the Folio 1020 chassis.
- Folio 1020 and 1020 G1 compatibility: Every variant in the EliteBook Folio 1020 G1 lineup — including CTO, G9P64AV, and L7Z19PA configurations — runs the same 7.6V rail with the same BMS handshake protocol. One battery fits all of them because HP standardised the power architecture across the entire platform.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Folio 1020 G1. The BMS negotiated charge termination correctly at 8.7V, held the protection thresholds, and passed data back to the HP battery driver without throwing unknown-device errors.
- Post-installation calibration on the Folio 1020: After fitting this battery, drain the laptop fully to hibernate cutoff — do not force shutdown — then charge uninterrupted to 100%. This triggers the BIOS battery learn cycle, resets the fuel gauge IC against the new cell's actual capacity, and clears the inaccurate health warning that appears after every cell swap.
BIOS reporting poor battery health immediately after fitting a new cell
The HP BIOS reads battery health from EEPROM data stored on the battery controller, not from live cell voltage. When a new cell is installed, the EEPROM registers zero charge history, and the BIOS interprets that absence as degraded health. This is a firmware behaviour, not a fault with the replacement cell. Running one full discharge-to-hibernate cycle followed by a complete uninterrupted charge clears the flag. After two to three full cycles, the BIOS health readout stabilises and reflects the cell's actual condition.
Folio 1020 shutting down at 20–30% battery shown on screen
This happens when the fuel gauge IC still holds calibration data from the old degraded cell. The gauge believes 20% remaining is the safe cutoff point because that is where the original cell's voltage cliff sat. The new cell has a different discharge curve, so the OS shuts the machine down while usable capacity remains. Run the full discharge-to-hibernate calibration cycle described above — the fuel gauge IC recalibrates its curve against the new cell and the cutoff voltage resets to the correct 6.0V floor.