About this replacement
Sony VAIO Duo 13 — 7.5V Li-Polymer Replacement Battery (VGP-BPS36)
This is a 7.5V Li-Polymer battery rated at 6300mAh (47.25Wh), built to replace the original VGP-BPS36 pack in the Sony VAIO Duo 13 convertible ultrabook. It fits the SVD1322ZPWR, SVP1321ZPWR, SVD13236PW, and related SVD/SVP13-series models. Install it when the original cell no longer holds a working charge through a normal computing session.
- VAIO Duo 13 / SVD13 platform fit: These models share the VGP-BPS36 form factor — same flat Li-Polymer profile (278.30 × 115.50 × 5.50mm), same 7.5V rail, and the same BMS handshake the VAIO EC expects on startup. SVD and SVP13 variants that shipped with this pack accept this cell without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on a VAIO Duo 13 chassis and confirmed the BMS communicated capacity data correctly to the firmware. The protection circuit tripped as expected at low-voltage cutoff with no false shutdowns mid-cycle.
- Post-install calibration on the VAIO Duo 13: After fitting this cell, run one full discharge to hibernate cutoff, then charge uninterrupted to 100% without interruption. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting poor battery health immediately after fitting the VGP-BPS36
The VAIO firmware reads health data stored in the old cell's EEPROM and compares it against the new cell's reported state. A fresh cell with no cycle history triggers a mismatch flag, so the BIOS displays a degraded-health warning even though the cell is new. This is a firmware calibration issue, not a fault with the replacement pack. Run a full discharge-to-hibernate then a full uninterrupted charge to 100% — the BIOS learn cycle will reset and the warning clears on the next boot.
VAIO Duo 13 shutting down at 20–30% charge shown on the fuel gauge
This happens when the fuel gauge IC is still calibrated to the old cell's voltage curve. The gauge reads 20–30% remaining, but the IC is mapping that percentage against a degraded cell's capacity profile — so the actual voltage has already dropped below safe operating threshold. Under combined CPU and display load, the voltage cliff arrives faster than the inaccurate gauge predicts, and the laptop cuts out to protect the circuit. Run two or three full discharge-to-hibernate and charge-to-100% cycles so the fuel gauge IC recalibrates against the new cell's actual voltage curve.