About this replacement
Toshiba Satellite T4700CS Series — 12V Ni-MH Replacement Battery (PA2420U)
This is a 12V, 4000mAh (48Wh) Ni-MH replacement battery for the Toshiba Satellite T4700CS and related early-generation Toshiba notebook computers. It also fits the Satellite T1960CS, T1950, and T1900 series. Install this when the original cell no longer holds a charge or fails to power the laptop off AC.
- Satellite T-series compatibility: These early Toshiba notebooks share the same 12V Ni-MH power rail, connector pinout, and charge circuit across the T1900, T1950, T1960CS, and T4700CS lines. One cell covers the full group because Toshiba held the same battery spec across that generation.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Satellite-series unit. The charge circuit accepted the cell without error, and the BMS did not trip on startup or mid-session load from the display and CPU together.
- Ni-MH recalibration after install: After fitting this cell, run one full discharge to hibernate-cutoff then charge uninterrupted to 100%. Ni-MH cells need this cycle for the BIOS battery learn routine to register accurate state-of-charge data against the new chemistry.
BIOS reporting poor battery health immediately after swapping the T4700CS cell
The Toshiba Satellite BIOS stores battery health data in EEPROM from the previous cell. When a new cell goes in, that stale data makes the system flag poor health before the new cell has been characterised. This is a firmware state — not a fault with the replacement. Run one complete discharge-to-hibernate followed by a full uninterrupted charge. After that cycle, the BIOS learn routine overwrites the old EEPROM values and the health warning clears.
Satellite T4700CS shutting down at 20–30% charge shown on screen
This happens when the cell voltage drops below the BIOS cutoff threshold under combined CPU and display load, even though the fuel gauge still shows charge remaining. The fuel gauge IC is reading an uncalibrated state-of-charge curve — it hasn't mapped the new cell's actual voltage profile yet. The fix is completing two to three full discharge-and-charge cycles so the gauge IC can build an accurate discharge curve. After calibration, the laptop will sustain load down to the correct cutoff near 10.8V rather than tripping early.