About this replacement
Asus Zenbook Flip 13 UX362FA — 11.55V Li-Polymer Replacement Battery (C31N1816)
This is an 11.55V, 4250mAh (49.09Wh) Li-Polymer battery for the Asus Zenbook Flip 13 UX362FA-EL090T and related UX362 and UX433 series convertible laptops. It replaces OEM part numbers C31N1816 and 0B200-03160000. Install it when the original cell no longer holds a usable charge or the laptop won't run unplugged.
- UX362 and UX433 series compatibility: These models share the same three-cell Li-Polymer pack architecture, 11.55V nominal voltage rail, and connector pinout — the BMS handshake signal and thermistor line are identical across the UX362FA and UX433FQ variants, so one cell works across both platforms.
- Bench tested on actual hardware: We ran this cell on the UX362FA and monitored the BMS through charge and discharge cycles. The protection circuit engaged correctly at low-voltage cutoff, and the charge IC accepted the cell without triggering a fault condition.
- Post-install calibration on UX362FA: After fitting this cell, run the laptop down to automatic hibernate cutoff — do not force-shutdown — then charge in one uninterrupted session to 100%. 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 new cell
The Asus BIOS reads health data from the battery's EEPROM, which stores cycle count and wear metrics from the previous cell. When a new cell is fitted, the BIOS compares the new cell's fresh EEPROM against the laptop's stored baseline and flags a mismatch as degraded health. This is a firmware read issue, not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to re-write the battery learn data against the new cell's actual chemistry. After one or two cycles, the health reading normalises.
Laptop cuts out at 20–30% charge shown on the UX362FA
This happens when the fuel gauge IC hasn't calibrated against the new cell's discharge curve. The IC uses a stored model from the previous cell, so it misreads the voltage slope and calls empty too early. Under combined CPU and display load, the voltage cliff arrives sooner than the gauge predicts, triggering an abrupt shutdown. Run two full discharge-to-hibernate cycles with an uninterrupted charge to 100% after each — the fuel gauge IC re-maps the curve and the shutdowns stop. Confirm the cell is reading correctly by checking the BIOS battery page for a Wh figure near 49Wh.