About this replacement
Asus Q304UA / TP301 Series — 11.55V Li-Polymer Replacement Battery (C31N1517)
This is a 11.55V, 4750mAh (54.86Wh) Li-Polymer replacement battery for the Asus Q304UA and TP301 series convertible notebooks. It fits the flip-hinge 2-in-1 form factor where the original C31N1517 cell degrades and stops holding charge. OEM part numbers 0B200-01840000, 0B200-01840100, and 0B200-01840200 all cross to this cell.
- Q304UA and TP301 series compatibility: These models share the same battery bay geometry, connector pinout, and BMS handshake protocol. The 3-cell Li-Polymer pack runs a single voltage rail at 11.55V nominal, and the EC chip expects the same EEPROM signature across the Q304UA, TP301U, and TP301UA variants.
- Bench tested on actual hardware: We cycled this cell on a TP301UA chassis and monitored BMS communication through the SMBus line. The cell accepted a full charge to 12.6V, and the BMS reported state-of-charge accurately after two calibration cycles. No fault codes triggered during discharge to cutoff.
- First-cycle calibration on the Q304UA: After installing, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. The Asus EC firmware reads EEPROM capacity data on the first full cycle. Skipping this step leaves the BIOS fuel gauge calculating against stale data from the old cell, which causes inaccurate percentage readings from day one.
Why the Q304UA BIOS flags a new battery as poor health immediately after swap
The Asus EC stores battery health data in EEPROM on the original cell. When a new cell goes in, that EEPROM history is absent or mismatched, so the BIOS reads zero charge cycles as an error state rather than a fresh cell. Windows Battery Report will also show a low full-charge capacity figure at this stage. Running one complete discharge-to-hibernate and uninterrupted recharge to 100% forces the EC to write a new baseline. After that cycle, the health warning clears and the fuel gauge tracks correctly.
Q304UA shutting down abruptly at 20–30% charge shown
This is a voltage cliff, not a capacity issue. Under combined CPU and display load, cell voltage drops faster than the fuel gauge IC can recalculate — the EC sees voltage fall below the hardware cutoff threshold before the displayed percentage catches up. It happens most often on a cell that has not yet been calibrated against the new chemistry. Run a full discharge cycle to hibernate-cutoff so the fuel gauge IC maps the actual discharge curve of the new cell. After one or two calibration cycles the shutdown point moves back to the correct low-voltage threshold near 3.0V per cell.