About this replacement
Sony VAIO Fit 13A — 11.25V Li-Polymer Replacement Battery (VGP-BPS41)
This 11.25V, 3140mAh (35.33Wh) Li-Polymer battery replaces the VGP-BPS41 in Sony VAIO Fit 13A notebooks. It fits the SVF13N27PW/B, SVF13N17PW/B, SVF13N12CW, and over 70 additional SVF13N variants. The connector, cell count, and BMS handshake match the original Sony specification.
- SVF13N series compatibility: All SVF13N variants share the same three-cell Li-Polymer stack, the same flat 315mm × 130mm form factor, and the same five-pin SMBus connector. A single VGP-BPS41 footprint covers the full sub-series without modification.
- Bench tested on actual hardware: We ran this cell in an SVF13N chassis through charge and discharge cycles. The BMS communicated state-of-charge data correctly over SMBus, charge termination triggered at full voltage, and no fault flags appeared in the VAIO battery status register.
- First-cycle calibration on the VAIO Fit 13A: After fitting the new cell, run one full discharge until the laptop hibernates on its own, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell's actual capacity and clears the inaccurate health warning that appears after every cell swap.
BIOS reporting poor battery health immediately after swapping VGP-BPS41
The VAIO firmware reads learned capacity data stored in the old cell's EEPROM and compares it against the new cell's reported state. Because the new cell has no charge history, the BIOS flags it as degraded before any cycles run. This is a firmware artefact, not a fault with the replacement cell. Run two full discharge-to-hibernate and charge-to-100% cycles and the health indicator will update to reflect the new cell's actual capacity.
VAIO Fit 13A shutting down abruptly at 20–30% charge shown
The fuel gauge IC on the VAIO Fit 13A estimates remaining capacity from a table built on the old cell's voltage curve. A new Li-Polymer cell has a steeper voltage drop in the lower charge band, so the IC hits its cutoff threshold earlier than the displayed percentage suggests. The laptop is not actually at 20–30% — it has already reached the BMS minimum voltage. Two to three full calibration cycles correct the fuel gauge mapping. After calibration, shutdown should align with the displayed percentage at approximately 3.2V per cell.