About this replacement
Sony VAIO VGN-TX Series — 7.4V Li-ion Replacement Battery (VGP-BPL5)
This is a 7.4V, 11000mAh Li-ion replacement battery for the Sony VAIO VGN-TX56C/W and the broader VAIO VGN-TX ultraportable notebook line. It replaces OEM part numbers VGP-BPL5, VGP-BPL5A, VGP-BPS5, and VGP-BPS5A. The original cells in these machines degrade after a few hundred cycles — this cell restores full capacity in a chassis that Sony no longer supports with new parts.
- VAIO VGN-TX platform fit: The TX series shares a single battery bay geometry, a 7.4V two-cell rail, and the same BMS connector across the VGN-TX16SP/W, VGN-TX2XP/L, VGN-TX37TP, and VGN-TX56C/W. All these models read battery state via the same SMBus protocol, so one cell works across the full TX lineup without a firmware conflict.
- Bench tested on actual hardware: We ran this cell on a VGN-TX unit under a controlled load cycle. The BMS accepted the cell without error, communicated charge state correctly over SMBus, and the cell held voltage above 7.0V through a full discharge sweep to the low-voltage cutoff threshold.
- First-cycle reset for TX notebooks: After fitting this cell, run the laptop on battery until it hibernates at cutoff — do not interrupt — then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to rewrite against the new cell and clears the inaccurate health warning that appears in VAIO Control Center after every cell swap.
BIOS reporting poor battery health immediately after installing a new cell
The VAIO TX BIOS stores battery health data in EEPROM on the old cell. When a new cell goes in, the BIOS reads stale EEPROM figures and flags the battery as degraded before a single charge cycle has run. This is not a fault with the replacement cell. Run one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100% — this triggers the learn cycle and overwrites the old EEPROM reference. After two to three full cycles, VAIO Control Center will show accurate health figures.
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 voltage curve. The IC is still using the discharge profile from the degraded original cell, so it misjudges the voltage cliff and trips a shutdown early. It is not a BMS fault or a bad cell. Run three full discharge-to-hibernate cycles with uninterrupted charges to 100% between each — the fuel gauge IC recalibrates across those cycles and the shutdown point will move back to near 0%. After calibration, the gauge cutoff aligns with the cell's true low-voltage threshold of approximately 6.0V.