Asus Eee PC X101 Replacement Battery A31-X101 10.8V 2200mAh

Asus Eee PC X101 Series — 10.8V Li-ion Replacement Battery (A31-X101)

This is a 10.8V, 2200mAh (23.76Wh) Li-ion battery for the Asus Eee PC X101, X101C, X101CH, and X101H. It replaces OEM parts A31-X101, A32-X101, X10L65H, and associated Asus part strings. The X101 is a compact 10-inch netbook — this cell restores portable operation when the original no longer holds a usable charge.

• X101 series compatibility: The X101, X101C, X101CH, and X101H share the same battery bay dimensions, connector pinout, and BMS handshake protocol. All four models draw from the same 10.8V rail, so one cell fits the entire lineup without modification.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on the X101CH. The BMS communicated correctly with the BIOS, charge termination triggered at 100%, and the protection circuit responded to over-discharge as expected.
• Post-install discharge cycle on the X101: After fitting this cell, run one full discharge until the netbook hibernates, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears on first boot after any cell swap.

Why the Eee PC X101 shuts down at 20–30% battery shown

The X101's Atom processor and display draw enough combined current that a degraded or freshly swapped cell hits a voltage cliff before the fuel gauge reaches zero. The BIOS reads the cell voltage and cuts power to protect the hardware — even though the percentage indicator still shows charge remaining. This happens because the fuel gauge IC calibrated its state-of-charge map against the old cell's discharge curve. After two or three full discharge-recharge cycles on the new cell, the IC recalibrates and the shutdown point moves back toward 0%.

BIOS reporting the new battery as 0% or unknown on first boot

The EEPROM in the old battery stored cycle count, health status, and capacity data that the BIOS used as its reference. When a new cell is installed, that EEPROM data is absent or mismatched, so the BIOS flags the battery as unknown or critically low. This is not a fault with the replacement cell. Boot into the BIOS setup screen, confirm the battery is detected on the hardware level, then perform the full discharge-to-hibernate and uninterrupted recharge cycle. After one complete cycle, the BIOS repopulates its battery data and the health indicator returns to normal.