About this replacement
Asus Transformer Book T100 Series — 3.8V Li-Polymer Replacement Battery (C12N1320)
This is a 3.8V, 8150mAh (30.97Wh) Li-Polymer battery for the tablet portion of the Asus Transformer Book T100 series. It fits the T100, T100T, and T100TA — the 10-inch detachable tablet that pairs with a keyboard dock. When the original cell degrades and the tablet stops holding charge, this swap restores it to a working state.
- T100 series tablet bay fitment: The T100, T100T, and T100TA all use the same tablet chassis with the same connector position and BMS handshake protocol. OEM part numbers C12N1320, 0B200-00720300, 0B200-00720100, and 0B200-00720400 all cross-reference to this cell configuration.
- Bench tested on actual hardware: We ran this battery through charge and discharge cycles on T100TA hardware. The BMS accepted the cell, charge IC negotiated correctly, and the fuel gauge reported voltage without fault flags during the test cycle.
- Post-swap fuel gauge reset: After installing this battery, run the tablet down to automatic shutoff — do not force it off — then charge uninterrupted to 100%. This single full cycle lets the fuel gauge IC recalibrate against the new cell's actual voltage curve.
Tablet showing wrong battery percentage after battery swap
The T100's fuel gauge IC learns the charge curve of the cell it was calibrated against. Swap the physical cell without recalibrating and the IC keeps reading against the old cell's profile. This causes the percentage display to jump, stall, or report full charge at a lower actual voltage. One complete discharge-to-shutoff followed by an uninterrupted charge to 100% resets the calibration reference and corrects the display.
T100 tablet shutting down unexpectedly at 15–25% remaining
The display backlight and active WiFi together pull a combined load that causes a brief voltage sag on a partially discharged cell. If the BMS detects the cell voltage drop below its cutoff threshold during that sag — even momentarily — it trips and shuts the tablet down before the percentage gauge reaches zero. This is not a defective battery; it reflects a miscalibrated fuel gauge reading the state of charge too optimistically. Run one full discharge cycle and confirm the cell rests above 3.6V at the 20% mark after recalibration.