About this replacement
Asus ExpertBook B9450 — 15.4V Li-Polymer Replacement Battery (C41N1903)
This is a 15.4V, 4200mAh (64.68Wh) Li-Polymer battery for the Asus ExpertBook B9450 series ultraportable business laptop. It fits the B9450FA-BM0160R, B9450FA-BM0193R, B9450FA-BM0165R, and related B9450 variants. OEM part numbers C41N1903 and 0B200-03560100 both cross to this cell.
- B9450 series fitment: All B9450FA variants share the same 15.4V four-cell Li-Polymer configuration, connector pinout, and BMS communication protocol. A single cell works across the full sub-series because Asus kept the power rail and EEPROM handshake identical across SKUs.
- Bench tested on actual hardware: We cycled this battery through charge, full discharge to BMS cutoff, and recharge on B9450 hardware. The BMS negotiated cleanly, charge current ramped correctly through CC and CV phases, and no protection trips occurred under sustained CPU and display load.
- Post-install calibration on the B9450: After fitting, run a full discharge until the laptop hibernates on its own, then charge uninterrupted to 100% without using the machine. This resets the BIOS battery learn cycle and clears the inaccurate health warning the B9450 displays after every cell swap.
BIOS reporting poor battery health immediately after fitting a new cell
The B9450 BIOS reads health data from EEPROM registers on the battery controller, not from live cell measurements. When a new cell arrives, those registers hold factory defaults that don't match the BIOS's learned baseline from the old pack. The system flags this mismatch as degraded health before any real-world cycling has occurred. One full discharge-to-hibernate followed by an uninterrupted charge to 100% lets the BIOS rewrite its learn cycle data and clear the warning.
B9450 shutting down at 20–30% charge shown on screen
This is a fuel gauge IC calibration issue, not a faulty cell. The fuel gauge IC still has the discharge curve from the old, degraded pack loaded into its model — so its percentage readings diverge sharply from actual cell voltage as load increases. Under peak CPU and display draw, the real cell voltage drops faster than the gauge expects, and the BMS triggers a protective cutoff before the display reads zero. Run two to three full discharge-to-hibernate and charge-to-100% cycles to let the fuel gauge IC re-map its discharge curve against the new cell chemistry. After calibration, the B9450 should sustain load down to approximately 3.2V per cell before cutoff.