Toshiba Portege 300 10.8V Replacement Battery PA2441UR 3000mAh

Toshiba Portege 300CT Series — 10.8V Li-ion Replacement Battery (PA2441UR)

This 10.8V, 3000mAh (32.4Wh) Li-ion battery replaces the original cell in the Toshiba Portege 300CT family of ultraportable business laptops. It fits the Portege 300/4.0 CT, 300CDS, 300CT, and 305CT, among others. OEM part numbers PA2441UR and PA2442UR both cross-reference to this cell.

• Portege 300 series compatibility: These models share the same battery bay dimensions, 10.8V power rail, and connector pinout. The BMS handshake protocol is consistent across the 300CT family, so the same cell works across all variants listed without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Portege 300CT platform. The BMS held charge cutoff correctly at 10.8V nominal and did not trigger premature low-voltage protection under standard CPU and display load.
• Post-install discharge cycle: After fitting this battery, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on these older Toshiba notebooks.

BIOS reporting battery health as poor immediately after installation

The Portege 300CT BIOS reads health data from EEPROM embedded in the original battery pack. When a new cell is installed, that EEPROM data does not match what the BIOS last recorded, so it flags the battery as degraded or unknown. This is a firmware recognition issue, not a fault with the replacement cell. Running one full discharge-to-hibernate followed by a complete uninterrupted charge allows the BIOS learn cycle to recalibrate against the new cell's actual capacity. After one or two cycles, the health indicator normalises.

Laptop shuts down at 20–30% charge remaining

This symptom appears when the fuel gauge IC still holds calibration data from the old, degraded cell. The gauge IC maps percentage readings to voltage curves it learned from the worn-out pack, so it misjudges the new cell's remaining capacity. Under full CPU plus display load, the actual cell voltage drops faster than the gauge expects, triggering a shutdown before the displayed percentage reaches zero. Force a complete discharge to hibernate-cutoff and a full recharge to 100% — repeat twice — to recalibrate the fuel gauge IC against the new cell's voltage curve.