Asus Transformer Book T100HA Replacement Battery 3.8V 7800mAh

Asus Transformer Book T100HA — 3.8V Li-Polymer Replacement Battery (C12N1435)

This 3.8V 7800mAh (29.64Wh) Li-Polymer battery is a direct cell replacement for the Asus Transformer Book T100HA. The T100HA is a 2-in-1 convertible that docks a 10-inch tablet into a keyboard base, and this battery sits inside the tablet portion of the unit. It matches the OEM part number C12N1435 and the slim 2.80mm profile required by the T100HA chassis.

• T100HA tablet unit fit: The T100HA tablet slab runs a single-cell 3.8V Li-Polymer pack — not the dual-cell arrangement found in the keyboard dock on some T100 variants. This cell matches that voltage rail and the flat 197.60 × 101.50mm footprint that fills the back of the tablet housing.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the T100HA, confirming the BMS handshake with the EC firmware, stable charge acceptance to 4.35V per cell, and clean cutoff at the low-voltage threshold without false trips.
• BIOS learn cycle after install: After fitting this cell, run the T100HA down to hibernate-cutoff on battery, then charge uninterrupted to 100% before resuming normal use. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears in Windows after every cell swap.

Why the T100HA BIOS reports poor battery health right after a new cell is fitted

The T100HA stores battery metadata — cycle count, design capacity, and health state — in EEPROM on the battery management circuit. When a new cell goes in, that EEPROM data does not automatically reset to match the fresh chemistry. The BIOS reads the old state and flags the battery as degraded before it has run a single cycle. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the EC to rewrite the learned capacity values against the new cell. After two or three cycles the health status in Windows Battery Report will normalise.

T100HA shutting down at 20–30% charge shown on screen

This happens when the fuel gauge IC still holds calibration data from the old, degraded cell. The IC maps 0% to a voltage that the new cell actually hits at 20–30% state of charge, so the system shuts down before the display reads zero. It is a calibration mismatch, not a fault with the replacement cell. Force a full discharge to hibernate-cutoff — do not manually power off — then charge to 100% uninterrupted. Repeat this cycle twice and the fuel gauge will re-anchor its 0% endpoint to the new cell's actual cutoff voltage of approximately 3.0V.