Sony VAIO PCG-TR1AP 11.1V Replacement Battery PCGA-BP2T

Sony VAIO PCG-TR1AP Series — 11.1V Li-ion Replacement Battery (PCGA-BP2T)

This is an 11.1V, 4400mAh (48.84Wh) Li-ion replacement battery for the Sony VAIO PCG-TR1AP and related TR-series ultraportable laptops. It fits the PCG-TR1, PCG-TR5PS, PCG-TR5AP, and over 30 additional VAIO TR-series models. Voltage, connector, and BMS handshake match the original PCGA-BP2T specification.

• VAIO TR-series compatibility: These models share the same 11.1V three-cell architecture, connector pinout, and SMBus communication protocol. Any cell meeting the PCGA-BP2T specification communicates correctly with the Sony EC firmware across all TR-series variants.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a PCG-TR1 unit. The BMS responded correctly at both the low-voltage cutoff and full-charge termination points, and the EC reported cell status without error flags.
• Post-install calibration on VAIO TR-series: After fitting this battery, run the laptop on battery only until it hibernates at the low-charge cutoff, then charge uninterrupted to 100% without interruption. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that typically appears after any cell swap.

BIOS reporting poor battery health immediately after fitting a new cell

The VAIO BIOS stores battery health data in EEPROM and compares the new cell's reported capacity against the degraded baseline from the old pack. A fresh cell with full capacity can actually trigger a mismatch warning because the numbers no longer align with the stored history. This is not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% clears the stored learn data and lets the BIOS re-establish its baseline against the new chemistry.

Laptop shuts down at 20–30% charge shown on the status bar

This symptom points to the fuel gauge IC losing calibration after the cell swap, not a fault in the new battery. The IC's internal model still reflects the old cell's voltage-to-capacity curve, so it misreads the remaining charge under load. When the CPU and display draw peak current simultaneously, the actual cell voltage drops below the cutoff threshold before the gauge reaches zero. Run two full discharge-to-hibernate and charge-to-100% cycles — after the second cycle, the gauge IC re-maps its curve to the new cell and the shutdown point corrects to below 5%.