Sony VAIO S11 Replacement Battery 7.6V 4500mAh VJ8BPS52

Sony VAIO S11 / S13 Series — 7.6V Li-Polymer Replacement Battery (VJ8BPS52)

This is a 7.6V, 4500mAh (34.2Wh) lithium-polymer battery that replaces the OEM part VJ8BPS52. It fits the Sony VAIO S11, VAIO S13, and extended model variants including VJ-S13-1X0111B and VJS131C0111B. The slim 6.74mm profile matches the original cell's form factor inside the chassis.

• VAIO S11 and S13 compatibility: Both the S11 and S13 share the same 7.6V battery rail, connector pinout, and BMS handshake protocol, which is why a single cell covers both platforms. The SMBus communication lines between the battery and the VAIO's EC controller use the same register map across this generation.
• Bench tested on actual hardware: We cycled this cell on an S13 chassis, monitoring BMS communication and charge termination. The protection circuit responded correctly to overvoltage, over-discharge, and thermal events without tripping a fault latch.
• First-cycle conditioning for VAIO S-series: 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 warning that appears after every cell swap on this platform.

Why the VAIO S11 shuts down at 20–30% after a battery swap

The VAIO's fuel gauge IC retains voltage-to-capacity mapping from the old, degraded cell. When the new cell hits a voltage point that the old map labelled as 20–30%, the EC triggers a forced shutdown — even though the new cell still has charge remaining. The fix is a full discharge-to-hibernate cycle followed by a complete charge. After two to three of these calibration cycles, the fuel gauge IC recalibrates against the new cell's actual discharge curve and the premature shutdowns stop.

BIOS reporting the replacement cell as "poor health" or unknown

This happens because the BIOS reads EEPROM health data written by the previous cell, not the physical state of the new one. The health register on the old cell accumulated cycle count and degradation flags that persist in the EC's memory after a swap. Run the Sony battery care utility or cycle the battery fully twice — charge to 100%, discharge to hibernate cutoff, repeat. After two full cycles, the BIOS recalculates health from live data and the warning clears.