About this replacement
Asus Transformer Book T300 Series — 7.4V Li-Polymer Replacement Battery (C22N1307)
This is a 7.4V 6750mAh (49.95Wh) Li-Polymer battery for the Asus Transformer Book T300 line. It fits the T300, T300L, T300LA, and T300CHI-F1-DB, among other variants in the same chassis. It replaces OEM part numbers C22N1307 and 0B200-00570000.
- T300 series compatibility: These models share the same internal battery bay geometry, two-cell 7.4V configuration, and BMS connector pinout. The T300CHI uses the same flat Li-Polymer form factor at 5.23mm thin — swapping between variants in this line works without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the T300 platform. The BMS handshake completed without error flags, charge termination triggered correctly at full cell voltage, and the protection circuit tripped at the expected low-voltage cutoff point.
- First-cycle calibration on the T300: After installation, run a full discharge until the device hibernates, then charge uninterrupted to 100% without using the machine. This resets the BIOS battery learn cycle and clears the inaccurate health or low-capacity warning that appears after every cell swap on this platform.
Why the T300 reports poor battery health immediately after a new cell install
The T300's embedded controller carries EEPROM data from the original cell — cycle count, wear level, and rated Wh — and compares that against what the new cell reports. A fresh cell with zero cycles reads as mismatched against the old EEPROM baseline, triggering a poor health flag in the BIOS and Windows battery report. This is a firmware accounting issue, not a fault with the replacement cell. Running one full discharge-to-hibernate followed by a complete uninterrupted charge clears the stored baseline and lets the controller rebuild its health data against the new cell's actual parameters.
T300 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The displayed percentage no longer matches actual cell voltage — the system hits a hard voltage floor and shuts down while the OS gauge still reads 20–30%. The cell itself is fine; the gauge just needs recalibration against the new chemistry. Do two full discharge-to-hibernate cycles followed by full uninterrupted charges — after the second cycle, the fuel gauge IC recalibrates and the shutdowns stop. If it persists after two cycles, check that the BIOS battery charge limit feature is not capped below 80%.