Asus C235VA Chromebook Compatible Battery 7.7V 4100mAh

Asus ChromeBook Flip CM3 Series — 7.7V Li-Polymer Replacement Battery (C21N2003)

This is a 7.7V, 4100mAh (31.57Wh) lithium-polymer replacement battery for the Asus C235VA, CM3200FM1A, CM3200FVA, CM3200FDA, and related ChromeBook Flip CM3 models. It replaces OEM part numbers 0B200-03800100 and C21N2003. The cell fits the slim chassis of the 11.6-inch Chromebook platform used widely in schools and office environments.

• CM3 platform compatibility: The C235VA and CM3200 variants share the same 7.7V two-cell Li-Polymer architecture, connector pinout, and BMS handshake protocol — that is why a single cell covers the full model range listed above.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a CM3200 unit. The BMS accepted the cell without error flags, the charge controller reached full voltage, and the protection circuit triggered correctly at low-cell cutoff.
• Post-install calibration on ChromeOS: After fitting this battery, let the laptop discharge fully until ChromeOS forces shutdown — do not interrupt it. Then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap.

Why ChromeOS reports poor battery health immediately after a cell swap

The EC firmware on these Chromebooks reads EEPROM data written by the original cell during the factory learn cycle. A new cell arrives with no learned data, so the firmware flags it as degraded or unknown. This is not a fault with the replacement cell — it is a calibration state. Run one full discharge-to-shutdown followed by an uninterrupted charge to 100%, and the EC rewrites the EEPROM profile against the new cell's actual behaviour. The health warning clears after one to two completed cycles.

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

This happens when the fuel gauge IC has not yet mapped the new cell's voltage curve. The IC predicts remaining capacity using the old cell's data, so it underestimates how steeply voltage drops under combined CPU and display load. The result is an unexpected shutdown while the status bar still shows charge remaining. Fix this by completing two or three full discharge-to-hibernate and charge-to-100% cycles — after that the IC recalibrates its curve to the new cell and the gauge stabilises. Target a resting voltage of 8.55–8.65V at a reported 100% to confirm the gauge is tracking correctly.