About this replacement
Asus Chromebook C202 Series — 7.6V Li-Polymer Replacement Battery (C21N1530)
This is a 7.6V, 4900mAh (37.24Wh) Li-Polymer replacement battery for the Asus Chromebook C202 and C202SA series. It fits the OEM connector and sits within the same footprint as the original cell at 229.75 x 163.05 x 7.04mm. If the Chromebook no longer holds a charge or shuts down early, this cell replaces the degraded original.
- C202 and C202SA compatibility: The C202 and C202SA share the same battery bay, BMS handshake, and connector layout. The C21N1530 part number covers both variants, including the C202SA-2A and C202SA-YS01. The voltage rail and cell configuration are identical across the range.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a C202SA unit. The BMS accepted the cell without error, charge current ramped normally through CC/CV stages, and the protection circuit tripped at the correct low-voltage cutoff threshold.
- Post-install calibration on ChromeOS: After fitting, run the battery down to auto-shutdown via hibernation, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning ChromeOS displays after a cell swap.
ChromeOS reporting battery health as poor immediately after swap
ChromeOS reads battery health data from EEPROM on the battery controller, not from live cell measurements. When a new cell goes in, the OS compares the fresh EEPROM profile against charge history it already logged for the old cell. That mismatch triggers a false "poor health" or "replace soon" warning. Running one full discharge-to-cutoff cycle followed by an uninterrupted charge to 100% forces the firmware to rewrite the learn cycle data against the new cell's actual capacity.
Chromebook C202 shutting down at 20–30% battery shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's discharge curve. The old cell's curve is still stored, so the gauge misjudges how much voltage remains under CPU and display load. When the new cell hits its actual voltage floor under load, the system cuts out even though the screen shows charge remaining. Discharge the battery fully to hibernate-cutoff at least twice, charging to 100% each time, and the gauge re-maps the curve to the new cell — shutdowns below 20% should stop after two to three calibration cycles.