About this replacement
Toshiba Dynabook SS SX/190NR — 10.8V Li-ion Replacement Battery (PA3444U-1BAS)
This is a 10.8V, 3600mAh (38.88Wh) Li-ion replacement battery for the Toshiba Dynabook SS SX/190NR and related ultraportable notebooks. It also fits the Dynabook SS SX/290NR, Portege R200, and Dynabook SS S20 12L/2, among others. OEM part numbers covered include PA3444U-1BAS, PA3444U-1BRS, and PABAS063.
- Dynabook SS and Portege R200 platform fit: These models share the same 10.8V three-cell rail, connector pinout, and BMS handshake protocol — which is why one battery covers the full range. The fuel gauge IC communicates over the same SMBus line across all listed variants, so the OS reads capacity data without additional configuration.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Portege R200-class unit. The BMS accepted the charge controller handshake immediately, and the SMBus reported cell data without errors. Voltage held steady across the discharge curve with no unexpected cutoff events.
- Post-install discharge cycle on Dynabook SS units: After fitting this battery, run one full discharge down to hibernate-cutoff, then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell data, clearing the inaccurate health warning that appears after every cell swap on these Toshiba notebooks.
BIOS reporting poor battery health immediately after fitting a new cell
The Toshiba BIOS on these Dynabook and Portege units stores learned capacity data from the previous cell in non-volatile memory. When a new cell goes in, the BIOS compares live readings against that stale EEPROM data and flags a mismatch as poor health. This is not a fault with the replacement battery. One full discharge-to-hibernate followed by an uninterrupted charge to 100% triggers the learn cycle and rewrites the stored baseline. After two to three cycles the health indicator normalises.
Laptop shuts down with 20–30% charge still showing on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The OS fuel gauge was mapped to the old cell, so it misreads remaining capacity — the laptop hits the real voltage floor before the displayed percentage reaches zero. Run two full discharge-to-hibernate cycles followed by full uninterrupted charges. By the third cycle the fuel gauge IC recalibrates and the shutdown threshold aligns with the displayed percentage. If the issue persists past three cycles, check that the BIOS battery learn mode is not disabled — re-enable it under Toshiba HWSetup if needed.