About this replacement
Sony VAIO VGN-TZ Series — 11.1V Li-ion Replacement Battery (VGP-BPX11)
This 11.1V 6600mAh (73.26Wh) Li-ion battery replaces the OEM VGP-BPX11 unit in the Sony VAIO VGN-TZ series. It fits the VGN-TZ121, VGN-TZ130N/B, VGN-TZ131N, VGN-TZ132N, and over 100 additional TZ-series models. The cell matches the original voltage rail and connector spec so the VAIO powers on without modification.
- TZ-series platform fit: Every VGN-TZ model in this lineup shares the same 11.1V three-cell rail, connector pinout, and BMS handshake protocol. That common architecture is why one part number covers the full TZ range — the BIOS expects the same EEPROM data structure across all variants.
- Bench tested on actual hardware: We ran this cell through charge, idle draw, and sustained CPU load cycles on a TZ-series unit. The BMS communicated correctly with the VAIO's fuel gauge IC at every stage — no false-low alerts, no mid-cycle cutoffs.
- First-cycle calibration after install: After fitting this battery, run the laptop off battery power until it hibernates at cutoff, then charge uninterrupted to 100% without using the machine. This single discharge-to-recharge cycle resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.
VAIO TZ BIOS reporting poor health immediately after fitting a new cell
The VGN-TZ BIOS reads battery health from EEPROM data written by the previous cell — not from live voltage measurements. When a new cell arrives, the BIOS compares stored cycle count and capacity history against the fresh cell and flags a mismatch. This is a data conflict, not a hardware fault. One full calibration cycle — discharge to hibernate, then uninterrupted charge to 100% — rewrites the BIOS battery learn data and clears the warning.
Laptop shutting down at 20–30% charge shown on the gauge
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The IC is still referencing voltage thresholds mapped to the old, degraded cell — so it calls 0% too early. The fix is two to three full discharge-to-full-charge cycles without interruption. After those cycles, the gauge recalibrates and the cutoff point drops back to near 0% — confirmed at roughly 10.5V terminal voltage under load before hibernate kicks in.