Asus Q553U Replacement Battery 11.4V 3600mAh C31N1522

Asus Q553UB-BSI7T13 — 11.4V Li-Polymer Replacement Battery (C31N1522)

This 11.4V, 3600mAh (41.04Wh) lithium-polymer cell replaces the original C31N1522 battery in the Asus VivoBook Q553U and Q553UB-BSI7T13 laptops. It slots into the same bay and connects to the same three-cell management circuit the factory unit uses. OEM part number 0B200-01880000 cross-references to the same physical cell.

• Q553U / Q553UB platform fit: Both models share the same 11.4V three-cell Li-Polymer pack, the same connector pinout, and the same BMS handshake protocol. The charge controller negotiates with the EEPROM on the battery before accepting current — a mismatched cell will register as unknown and refuse to charge.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Q553U unit. The BMS accepted the handshake within two minutes of connection, charge current ramped normally to CC phase, and the fuel gauge IC began tracking cell state within the first cycle.
• First-cycle reset on the Q553U: After installing, let the laptop discharge fully until it hibernates on its own — do not force shutdown. Then charge uninterrupted to 100% without using the machine. This gives the BIOS battery learn cycle a clean reference point and clears the spurious "poor health" flag that appears after every cell swap on this platform.

BIOS reporting poor battery health immediately after fitting the C31N1522

The Q553U BIOS reads health data from the battery's EEPROM, not from live cell measurements. When a new cell arrives, the EEPROM values do not match the charge history the BIOS has built up from the old pack. The system flags the mismatch as degraded health. Running one complete discharge-to-hibernate then a full uninterrupted charge rewrites the BIOS reference data and clears the warning. After two to three cycles, the reported health percentage will stabilise at an accurate figure.

Laptop shutting down at 20–30% charge shown on screen

This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. Under full CPU and display load the new cell hits a voltage cliff that the uncalibrated gauge did not predict, so the system shuts down before the displayed percentage reaches zero. The fix is calibration: run the laptop at normal load — screen on, browser open — through three full discharge and charge cycles without interrupting them. By cycle three the gauge IC maps the new cell's actual voltage curve and the shutdowns stop.