About this replacement
Asus VivoBook Flip 14 TP401CA Series — 7.7V Li-Polymer Replacement Battery (C21N1714)
This 7.7V, 5000mAh (38.5Wh) lithium-polymer cell replaces the internal battery in the Asus VivoBook Flip 14 TP401CA-EC012T, TP401NA-EC007T, TP401MA-BZ031TS, TP401NA-BZ002T, and over 100 additional TP401 variants. It matches the OEM C21N1714 and 0B200-02740000 part numbers. The slim 5.56mm profile fits the TP401's low-clearance chassis without modification.
- TP401 platform compatibility: All TP401CA, TP401NA, and TP401MA models share the same 7.7V two-cell architecture, connector pinout, and BMS communication protocol — which is why a single C21N1714 cell spans the entire TP401 convertible line.
- Bench tested on actual hardware: We ran this cell on a TP401CA unit and confirmed the BMS handshake completed within two charge cycles — voltage stepped up cleanly from rest through CV phase with no cutoff interruptions.
- Post-install discharge cycle on the TP401: After fitting, run the laptop on battery only until it hibernates at the BIOS low-voltage cutoff, then charge uninterrupted to 100%. The TP401's fuel gauge IC needs this full sweep to calibrate against the new cell — skipping it leaves the OS reporting inaccurate charge percentages for weeks.
BIOS reporting poor battery health immediately after fitting the C21N1714
The TP401's BIOS reads health data from EEPROM registers written by the original cell over its lifetime. A new cell arrives with factory EEPROM values that don't match the wear history the BIOS expects, so it flags the battery as degraded before it's seen a single charge cycle. This is a data mismatch, not a cell fault. Run one full discharge-to-hibernate then a full uninterrupted charge — most TP401 units clear the warning after one to three cycles as the BMS rewrites the health registers. If the warning persists beyond three cycles, check BIOS version and update to the latest Asus firmware for the TP401 platform.
VivoBook Flip 14 shutting down at 20–30% charge shown on screen
This happens when the cell voltage drops below the BMS cutoff threshold under full load before the fuel gauge reaches zero — the display, processor, and convertible hinge sensors all draw simultaneously when the unit is in tablet or tent mode. The OS percentage you see is calculated from the previous cell's discharge curve, which no longer matches the new cell. The fuel gauge IC needs two to three full discharge-charge cycles to relearn the actual voltage-to-capacity curve of the replacement cell. Let the laptop discharge fully to hibernate cutoff at least twice, then charge to 100% each time, and the 20–30% shutdown will stop as the gauge aligns to 7.7V chemistry.