About this replacement
Toshiba Netbook NB100 Series — 7.2V Li-ion Replacement Battery (PA3689U-1BRS)
This is a 7.2V, 8800mAh Li-ion replacement battery for the Toshiba Netbook NB100 series. It fits the NB100, NB100-01G, NB100-111, NB100-12A, and more than 34 additional NB100 variants. Voltage and capacity match the original Toshiba specification — PA3689U-1BAS, PABAS155, PA3689U-1BRS, and PABAS156 are all covered by this cell.
- NB100 platform fit: Every NB100 variant on this list runs the same 7.2V battery rail with a shared connector pinout and BMS handshake protocol. A single cell covers the full range because Toshiba kept the power subsystem identical across the NB100 lineup.
- Bench tested on actual hardware: We ran this cell on an NB100 unit and confirmed the BMS negotiated correctly — charge current stepped down as expected at the top-of-charge threshold and the protection circuit tripped cleanly on simulated over-discharge.
- Post-install calibration on the NB100: After fitting this battery, run one full discharge until the system hibernates, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning the NB100 throws after every cell swap.
Why the NB100 BIOS flags a new battery as poor health immediately after swapping
The NB100 BIOS reads health data from EEPROM registers stored on the battery pack — not from the actual cell chemistry. When you install a new cell, those registers carry default or blank values the BIOS interprets as degraded. The health warning is a data mismatch, not a fault with the replacement battery. Running one full charge-discharge cycle allows the fuel gauge IC to write fresh capacity data to those registers. After one or two cycles the BIOS health reading corrects itself.
NB100 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The gauge was trained on the old, degraded cell and misjudges where the voltage cliff sits on the replacement. Under combined CPU and display load, the real cell voltage drops faster than the gauge predicts, triggering an emergency shutdown before the displayed percentage reaches zero. Discharge the battery fully to hibernate cutoff — the system will power off automatically — then charge to 100% without interruption. Repeat this once more and the gauge re-anchors to the correct voltage floor, typically settling around 6.4V under load.