About this replacement
Sony VAIO VPC-CA Series — 11.1V Li-ion Replacement Battery (VGP-BPS26A)
This is an 11.1V, 4400mAh (48.84Wh) lithium-ion replacement battery for the Sony VAIO VPC-CA series notebooks. It fits the VPC-CA16EC, VPC-CA17EC, VPC-CA18EC, VPC-CA26EC, and over 660 additional VAIO models that share the same battery bay and connector. OEM part numbers covered include VGP-BPS26A, VGP-BPS26, and VGP-BPL26.
- VAIO VPC-CA platform compatibility: These CA-series models share a unified 11.1V three-cell battery rail, a common 272mm bay form factor, and the same BMS handshake protocol — which is why a single cell works across all of them without firmware conflicts.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on VPC-CA hardware. The BMS completed full charge acceptance without triggering overvoltage cutoff, and the protection circuit responded correctly to load fluctuations at the cell level.
- Post-install calibration on the VAIO VPC-CA: After fitting this cell, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the VAIO VPC-CA reports poor battery health immediately after a replacement
The VAIO's BIOS reads health data from EEPROM stored on the battery's BMS — not from live cell measurements. When a new cell arrives, that EEPROM carries fresh default values that don't match the charge history the BIOS expects to see. The result is a "poor health" or "replace battery" warning even though the cell is brand new. One full discharge-to-hibernate followed by an uninterrupted charge to 100% lets the BIOS rewrite its learned capacity baseline against the new cell's actual chemistry.
VAIO VPC-CA shutting down at 20–30% charge shown on screen
This happens when the cell voltage drops sharply under combined CPU and display load — what's called a voltage cliff. The fuel gauge IC estimates remaining capacity under light load, but the BIOS pulls the plug when actual cell voltage falls below the protection threshold during a heavy-draw spike. It is not a BMS fault or a firmware lock. Run two full calibration cycles — discharge to hibernate cutoff, charge to 100% uninterrupted — and the fuel gauge IC will map the new cell's discharge curve accurately. After calibration, the reported percentage and actual shutdown point will align.