About this replacement
Asus VivoBook X453 Series — 7.6V Li-ion Replacement Battery (B21N1329)
This is a 7.6V, 4000mAh (30.4Wh) Li-ion replacement battery for the Asus VivoBook X453 and X453MA notebook series. It slots into the same bay as the original and connects via the same Asus two-cell connector. Covers OEM part numbers B21N1329, 0B200-00840000, and the full 0B200-008404xx–008407xx range.
- X453 and X453MA compatibility: Both the standard X453 and X453MA share a two-cell 7.6V architecture with the same BMS handshake protocol. The cell count and connector pinout are identical across the 0122CN3530 and 0132DN3530 sub-models, so one battery covers the entire range without modification.
- Bench tested on actual hardware: We cycled this cell on an X453MA and confirmed the BMS accepted the new EEPROM data without fault codes. Charge acceptance reached full 4000mAh capacity within the first two cycles, and the protection circuit tripped correctly at low-voltage cutoff.
- First-cycle calibration on the X453MA: After fitting the new cell, run one full discharge down to hibernate-cutoff, then charge uninterrupted to 100%. This forces the X453 fuel gauge IC to relearn against the new cell's actual capacity curve and clears the false "poor health" warning that BIOS typically throws after any cell swap.
BIOS reporting battery health as poor immediately after fitting the X453 replacement
When the X453 BIOS reads "poor health" right after a swap, it is reading stale data from the previous cell's EEPROM profile, not the actual state of the new cell. The fuel gauge IC stores learned capacity data and compares it against a fixed Wh reference — a brand-new cell with no history looks degraded by that measure. One full discharge-to-hibernate followed by an uninterrupted charge to 100% resets the learn cycle. After two to three full cycles the BIOS health indicator should update to normal.
X453 shutting down suddenly while the OS still shows 20–30% remaining
This happens when the cell voltage drops sharply under combined CPU and display load — a voltage cliff the fuel gauge did not predict. The OS percentage is calculated from a capacity model, not live cell voltage, so the reading lags behind the actual drop. The BMS hits its low-voltage cutoff before the gauge reaches 0%, causing an abrupt shutdown. Run two full calibration cycles as described above; if shutdowns persist below 25%, check that the BIOS is not running a charge-limit profile that artificially caps usable capacity.