About this replacement
Toshiba Satellite NB200 / NB205 Series — 10.8V Li-ion Replacement Battery (PA3731U-1BRS)
This is a 10.8V, 4400mAh (47.52Wh) Li-ion replacement battery for the Toshiba Satellite NB200, NB201, NB205, and NB200-110 netbooks. It uses OEM part numbers PA3731U-1BRS, PA3734U-1BRS, PA3733U-1BRS, and PA3732U-1BAS. Cross-references GC02000XV10 and PABAS209 also apply to the same cell group.
- NB200/NB201/NB205 battery platform: These three models share a common 10.8V three-cell series configuration, the same physical connector pinout, and an identical BMS handshake protocol — which is why one cell works across the entire NB2xx line.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the NB200 platform. The BMS negotiated correctly with the Toshiba charge controller, reached full charge without throttling, and the protection circuit tripped cleanly at the low-voltage cutoff without forcing a hard shutdown.
- Post-install calibration on the NB200: After fitting a new cell, let the battery discharge fully until the netbook hibernates, then charge uninterrupted to 100% without using the machine. This forces the BIOS battery learn cycle to reset against the new cell's actual capacity and clears the false "poor health" warning that appears after every cell swap.
Why the NB200 BIOS reports poor battery health after a cell swap
The Toshiba BIOS reads health data from EEPROM registers written by the original cell during its first charge cycles. When a new cell is fitted, those registers no longer match the cell's actual chemistry, so the BIOS flags the battery as degraded or unknown before any calibration has run. This is a data mismatch, not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the learn-cycle data and resolves the warning in most cases.
NB200 shutting down at 20–30% battery remaining
This happens when the fuel gauge IC has not yet calibrated against the new cell and is misreading the actual state of charge. Under combined CPU and display load, the cell voltage drops faster than the uncalibrated gauge predicts, and the BMS triggers a protective shutdown before the displayed percentage reaches zero. It is not a cell defect — it is a calibration gap. Run two full discharge-to-hibernate and full-recharge cycles; after that, the fuel gauge IC maps its readings to the new cell's voltage curve and the shutdowns stop.