About this replacement
Toshiba Satellite P200-1CB / X200-21W — 10.8V Li-ion Replacement Battery (PA3536U-1BRS)
This is a 10.8V, 4400mAh (47.52Wh) Li-ion replacement battery for the Toshiba Satellite P200-1CB and the wider Satellite P200 / P200D / X200 / P305 notebook series. It matches the OEM part numbers PA3536U-1BRS, PA3537U-1BRS, and PABAS100. If the original cell has degraded to the point where the laptop no longer holds a charge away from the AC adapter, this cell restores portable operation.
- Satellite P200 / X200 series fit: These models share the same 10.8V three-cell rail and the same PA3536U-1BRS connector and BMS handshake protocol. The battery management IC communicates battery state to the Toshiba Power Saver firmware, so the physical connector and the BMS data lines both have to match — and they do across this group.
- Bench tested on actual hardware: We ran this cell on a Satellite P200-series unit and confirmed the BMS completed a full charge cycle without tripping an over-voltage fault. The protection circuit responded correctly to load spikes from the CPU and GPU under sustained stress, cutting in at the expected threshold without dropping the system.
- Post-install calibration on Satellite P200: After fitting the new cell, run the laptop down to hibernate cutoff under normal load, then charge uninterrupted to 100% before using it again. This resets the BIOS battery learn cycle and clears the inaccurate health warning that typically appears in Toshiba Power Saver after every cell swap.
Why Toshiba BIOS reports poor battery health immediately after fitting a new cell
The Satellite P200 BIOS stores capacity and health data in EEPROM on the battery pack itself. When a new cell goes in, that EEPROM data does not match the BIOS's learned baseline for the old pack. The firmware interprets the mismatch as a degraded or unknown battery rather than a new one. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS to re-learn the cell's actual capacity curve. After one or two of these cycles, the health indicator and charge percentage stabilise.
Satellite P200 shutting down at 15–25% charge shown on screen
This is a voltage cliff failure, not a capacity problem. Under full CPU and display load, the cell voltage drops faster than the fuel gauge IC can track, and the system hits the low-voltage shutdown threshold before the displayed percentage reaches zero. It happens most often when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. Run two full discharge-to-hibernate cycles with the screen at full brightness and the CPU under normal load. After calibration, the gauge and the actual cell voltage will align, and the shutdown will move to the correct low-battery point — typically around 10.8V per pack under load.