About this replacement
Sony VAIO-CA46 / CA47 / CA48 Series — 11.1V Li-ion Replacement Battery (VGP-BPS34)
This is an 11.1V, 3600mAh (39.96Wh) Li-ion replacement battery pack for the Sony VAIO-CA and SVF15A series laptops. It fits the VAIO-CA46, CA47, CA48, SVF15A16SC, and over 70 additional VAIO models that use the VGP-BPS34 or VGP-BPL34 OEM part number. The connector, BMS handshake, and cell voltage match the original Sony specification.
- VAIO-CA and SVF15A platform fit: These models share a common battery bay dimension, locking tab position, and BMS communication protocol. The fuel gauge IC on the motherboard reads EEPROM data from this pack the same way it read the original — no adapter or firmware patch needed.
- Bench tested on actual hardware: We ran this pack on the SVF15A platform under sustained CPU and display load. The BMS held voltage above 10.5V through discharge and accepted a full charge cycle without tripping the over-voltage cutoff.
- First-cycle calibration on VAIO laptops: After installing, run one full discharge until the laptop hibernates, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health or low-capacity warning that appears after every cell swap on VAIO hardware.
BIOS reporting poor battery health immediately after swapping the VGP-BPS34
The VAIO BIOS reads design capacity from the pack's EEPROM and compares it against a learned charge history stored from the old cell. A fresh pack has no charge history, so the BIOS flags it as degraded or unknown on first boot. This is a firmware interpretation issue, not a cell fault. Running one complete discharge-to-hibernate then a full uninterrupted charge gives the BIOS enough data to reset its health estimate. After two or three full cycles, the health indicator stabilises at normal.
Laptop shuts down at 20–30% shown on the fuel gauge
This happens when the fuel gauge IC is still calibrated to the old cell's voltage curve. A worn cell holds a higher resting voltage at low charge than a fresh one, so the gauge overestimates remaining charge — then the new cell hits its voltage cliff and the laptop cuts out abruptly. The fix is calibration: discharge fully to hibernate, charge to 100% without interruption, and repeat twice. After calibration, the fuel gauge tracks the new cell's actual voltage curve and low-battery warnings fire at the correct state of charge above 10.8V.