About this replacement
Asus Chromebook Flip C302CA Series — 7.7V Li-Polymer Replacement Battery (C21N1613)
This 7.7V, 4800mAh (36.96Wh) lithium-polymer battery replaces the OEM C21N1613 cell in the Asus Chromebook Flip C302CA line. It fits the C302CA-DH75, C302CA-GU005, C302CA-0041A6Y30, C302CA-GU017, and over 19 additional C302CA variants. All share the same two-cell Li-Polymer pack, connector pinout, and BMS communication protocol.
- C302CA platform compatibility: Every C302CA variant listed runs the same 7.7V dual-cell architecture with a shared connector and identical BMS handshake. The charge controller reads cell chemistry and voltage tolerance from the same register set across all SKUs — one battery fits the entire line without modification.
- Bench tested on actual hardware: We ran this cell in a C302CA-DH75 chassis through charge, discharge, and resume-from-sleep cycles. The BMS accepted the cell on first insertion, reported state-of-charge correctly, and showed no protection trips during CPU and display load.
- Post-swap discharge cycle on the C302CA: After installing, run the device from 100% down to automatic hibernate cutoff, then charge uninterrupted back to 100%. This forces the Chromebook's fuel gauge IC to re-learn the new cell's voltage curve and clears the inaccurate battery health warning that appears in Chrome OS diagnostics after every cell swap.
Why Chrome OS diagnostics flags a new C302CA battery as "poor health"
Chrome OS reads battery health from EEPROM data written by the original cell's embedded controller. When a new cell is installed, the EEPROM charge-cycle counter and wear estimate still reflect the old pack — the OS has no way to know a swap occurred. The health percentage shown in the Diagnostics app is calculated against that stale data, not the actual cell condition. Running one full discharge-to-hibernate then a full uninterrupted charge resets the learn cycle and forces the fuel gauge IC to write fresh baseline data to match the new cell.
C302CA shutting down at 20–30% charge remaining after battery replacement
This happens because the fuel gauge IC has not yet calibrated its voltage-to-capacity curve against the new cell. Under combined CPU and display load, the cell voltage drops faster than the uncalibrated gauge predicts, and the system hits the low-voltage protection threshold before the displayed percentage reaches zero. The Chromebook interprets this as an emergency cutoff and shuts down immediately. Complete two full discharge-to-hibernate and charge-to-100% cycles — after the second cycle the gauge stabilises and the premature shutdowns stop. If cutoff still occurs after two cycles, check that the EC firmware is current via Chrome OS update before replacing the cell again.