About this replacement
Asus U30JC / U35 / U45 Series — 14.8V Li-ion Replacement Battery (A32-UL30 / A42-UL80)
This 14.8V, 6600mAh (97.68Wh) Li-ion battery replaces the original cell in Asus U30JC, U35, U35JC, U45, and related UL-series laptops. It matches the OEM voltage rail and connector pinout for the affected models. Install it when the original battery no longer holds a usable charge during unplugged use.
- U30 / U35 / U45 platform compatibility: These models share a common battery bay form factor, 14.8V nominal rail, and the same four-pin BMS connector. The UL30, UL50, and UL80 sub-variants use identical BMS handshake logic, so one cell covers all of them without adapter or modification.
- Bench tested on actual hardware: We ran this cell on a U35JC unit and cycled it through full charge and discharge sequences. The BMS negotiated correctly with the BIOS on first insertion, and the charge circuit accepted the new cell without a BMS trip or error flag.
- Post-swap calibration on UL-series hardware: After fitting this battery, run a full discharge until the laptop hibernates at cutoff, then charge uninterrupted to 100% without interruption. This forces the BIOS battery learn cycle to recalibrate against the new cell and clears the false "poor health" or "0% capacity" flag that UL-series BIOS versions commonly report after every cell swap.
BIOS reporting poor battery health immediately after fitting a new cell
Asus UL-series laptops store battery health data in EEPROM on the BMS board. When a new cell is installed, the BIOS reads stale EEPROM data from the old battery's last recorded state and flags the replacement as degraded or unknown. This is a firmware read issue, not a fault with the new battery. Run one complete discharge-to-hibernate cycle followed by an uninterrupted full charge to allow the BIOS learn cycle to overwrite the old EEPROM values. After two full cycles, the health indicator should read accurately.
Laptop shuts down abruptly at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated to the new cell's discharge curve. The IC predicts cutoff using the old cell's voltage-to-capacity mapping, and the new cell hits a steeper voltage cliff at lower states of charge than the old worn cell did. The laptop interprets this voltage drop as an emergency cutoff before the displayed percentage reaches zero. Complete two full discharge-to-hibernate and charge-to-100% cycles without interruption — after that, the fuel gauge IC recalibrates and the shutdowns stop. The target charge floor before each hibernate trigger is the BIOS low-battery cutoff, typically around 10.5V under load.