About this replacement
Asus R553LN Series — 11.4V Li-Polymer Replacement Battery (B31N1336)
This is an 11.4V, 4200mAh (47.88Wh) lithium-polymer replacement battery for the Asus R553LN, R553LF, and related 15-inch notebook models. It replaces OEM part numbers B31N1336, C31-S551, 0B200-00450100, and several variants used across the R553 line. The cell fits the original bay and connects to the existing motherboard connector without modification.
- R553LN and R553LF platform fit: Both model lines share the same three-cell Li-Polymer configuration, voltage rail, and BMS connector pinout. Asus used the same battery across these variants, so one cell covers the entire group without adapter or wiring change.
- Bench tested on actual hardware: We ran this cell through charge, discharge, and charge-cycle verification on the R553LN platform. The BMS handshake completed correctly, charge acceptance registered across the full capacity range, and no protection-circuit trips occurred under standard CPU-plus-display load.
- Post-install calibration on R553 hardware: After fitting this cell, run the laptop down to hibernate cutoff under normal use — do not force-drain it — then charge uninterrupted to 100%. This single cycle resets the BIOS battery learn cycle and clears the inaccurate "poor health" or low-percentage warning that appears routinely after any cell swap on this platform.
Why the R553LN shuts down at 20–30% charge remaining
The R553LN fuel gauge IC holds calibration data from the previous cell. When a new cell goes in, the IC maps the old discharge curve onto the new cell's chemistry. Under full CPU load with the display at brightness, the new cell's voltage drops faster than the IC predicts at that state of charge. The BIOS reads the voltage cliff as zero capacity and triggers an immediate shutdown — even though the gauge still shows 20–30%. Running two complete discharge-to-hibernate-cutoff cycles followed by full uninterrupted charges forces the IC to rebuild its discharge curve against the actual cell, and the shutdowns stop.
BIOS reporting 0% or "Unknown" battery after fitting a new cell
The BIOS reads battery state from EEPROM data written by the original cell's protection circuit. A new cell arrives with its own EEPROM values, which the Asus firmware treats as unrecognised until the learn cycle completes. The system may show 0%, "Unknown," or refuse to charge past a low threshold on first boot. Plug in the AC adapter, leave the laptop powered on and charging without interruption until the indicator shows 100%, then reboot — the BIOS re-reads the EEPROM at full charge and clears the unknown-state flag.