About this replacement
Toshiba Satellite P55W-B Series — 14.4V Li-Polymer Replacement Battery (PA5189U-1BRS)
This is a 14.4V, 3850mAh (55.44Wh) lithium-polymer replacement battery for the Toshiba Satellite P55W-B notebook computer. It fits the P55W-B, P55W-B5224, P55W-B5318D, and related P55W models. The OEM part numbers PA5189U-1BRS and P000602690 confirm direct fitment across this convertible notebook series.
- P55W-B series fitment: These models share the same 14.4V battery rail, connector pinout, and BMS handshake protocol. Swapping between sub-models in this family carries no compatibility risk — the same cell and protection circuit serves the full group.
- Bench tested on actual hardware: We ran charge-discharge cycles on this cell against the P55W-B platform. The BMS communicated correctly with the BIOS, accepted a full charge to 100%, and did not trigger any low-voltage protection cutoff during high-CPU load testing.
- Post-install calibration on the P55W-B: After fitting this cell, run one full discharge until the laptop hibernates at low-battery cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears immediately after any cell swap on this platform.
BIOS reporting poor battery health immediately after replacement
The Toshiba BIOS on P55W-B models stores historical charge data in EEPROM linked to the original cell. When a new cell installs, that stored data no longer matches actual battery behaviour, so the system flags it as degraded. This is a firmware calibration issue, not a fault with the replacement cell. Run one full discharge to hibernate-cutoff, then a full uninterrupted charge to 100%. After one or two complete cycles, the BIOS recalibrates and the health warning clears.
Laptop shuts down at 20–30% charge shown on the fuel gauge
This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The IC still maps percentage readings against the old cell's degraded profile, so it misreads 20% as zero and triggers shutdown. It is not a fault in the replacement cell — it is a mismatch between the stored calibration data and the new chemistry. Force two full discharge-to-hibernate then full-recharge cycles without interruption. After the second cycle, the fuel gauge IC locks onto the correct voltage curve and the early shutdowns stop.