About this replacement
Asus Zenbook UX510UW Series — 11.1V Li-Polymer Replacement Battery (B31N1534)
This 11.1V, 3950mAh (43.85Wh) lithium-polymer battery replaces the OEM B31N1534 cell in the Asus Zenbook UX510UW series. It fits the UX510UW, UX510UW-1A, UX510UW-RB71, UX510UW-CN044T, and over 25 additional UX510UW variants. The thin 6.62mm profile matches the original cell's physical envelope exactly.
- UX510UW model family fit: All UX510UW variants share the same 11.1V power rail, three-cell Li-Polymer configuration, and B31N1534 connector pinout. The BMS handshake uses the same EEPROM authentication protocol across the entire UX510UW board revision, so one cell covers the full model range.
- Bench tested on actual hardware: We ran this cell on a UX510UW board and confirmed the BMS completed charge initialisation without fault codes. The protection circuit engaged at the correct low-voltage cutoff, and charge current stepped down cleanly in the CV phase near full capacity.
- Post-install calibration on the UX510UW: After fitting this cell, run the laptop down to hibernate cutoff under normal use, then charge uninterrupted to 100% without waking the system. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on UX510UW hardware.
BIOS reporting poor battery health immediately after fitting a new cell
The UX510UW BIOS reads health data from the cell's EEPROM, which stores cycle count, rated capacity, and charge history. A new cell arrives with a fresh EEPROM, and the BIOS interprets the mismatch between stored history and actual charge behaviour as degradation. This is a firmware calibration issue, not a fault with the replacement cell. Running one full discharge-to-hibernate then a full uninterrupted charge cycle gives the BIOS enough data to update its health register correctly.
Zenbook UX510UW shutting down abruptly while the OS still shows 20–25% remaining
This happens when the fuel gauge IC's discharge curve is calibrated against the old cell's degraded voltage profile. The IC predicts 20% remaining based on stale data, but the new cell's voltage cliff under combined CPU and display load sits at a different point. The system hits the hardware low-voltage cutoff before the OS gauge reaches zero. Two or three full discharge-to-hibernate and full-recharge cycles recalibrate the fuel gauge IC against the new cell's actual voltage curve, and the shutdowns stop.