About this replacement
Sony VAIO PCG-TR1MP Series — 11.1V Li-ion Replacement Battery (PCGA-BP3T)
This is an 11.1V, 6600mAh (73.26Wh) Li-ion replacement battery for the Sony VAIO TR series ultralight notebooks. It fits the PCG-TR1MP, PCG-TR5S, PCG-TR1A, PCG-TR1/B, and over 20 additional TR-series models using the PCGA-BP3T form factor. The cell matches the original voltage rail and connector so the BIOS can communicate with the battery management system correctly.
- TR-series compatibility: All listed TR models share the same 11.1V three-cell architecture, physical connector pinout, and BMS handshake protocol. Sony used this across the TR range without hardware revision, so one cell covers the full group without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on TR-series hardware. The BMS negotiated correctly with the BIOS, charge acceptance reached the rated 6600mAh ceiling, and the protection circuit tripped at the expected low-voltage threshold without premature cutoff.
- Post-install calibration on the TR series: After fitting this cell, run one full discharge until the laptop hibernates, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after a cell swap on these models.
Why the VAIO TR reports poor battery health immediately after a new cell is fitted
The TR series BIOS stores charge history and health data in EEPROM on the original battery's circuit board. When a replacement cell is installed, that EEPROM data is either blank or mismatched, so the BIOS flags the battery as degraded before it has run a single cycle. This is not a fault with the replacement cell. Running one full discharge-to-hibernate followed by a complete uninterrupted charge gives the fuel gauge IC enough data to overwrite the stale health reading. After two to three cycles, the BIOS health report stabilises to reflect actual cell capacity.
VAIO TR shutting down at 20–30% charge shown on the gauge
This happens when the cell voltage drops below the BIOS cutoff threshold under combined CPU and display load, even though the fuel gauge still reads 20–30%. The fuel gauge IC on the TR series is calibrated against the original cell's discharge curve — a new cell with a slightly different curve causes the gauge to misread remaining capacity. The laptop shuts down at what looks like 20–30% because the actual cell voltage has already hit the protection floor. To fix this, perform two full discharge-to-hibernate cycles followed by full charges; the fuel gauge IC recalibrates its curve to the new cell and the shutdown point shifts back to below 5%.