About this replacement
Asus ZenFone 3 Ultra ZU680KL — 3.85V Li-Polymer Replacement Battery (C11P1516)
This is a 3.85V, 4600mAh Li-Polymer replacement battery for the Asus ZenFone 3 Ultra and ZenFone 3 Ultra Dual SIM (ZU680KL). It fits both single and dual SIM variants that share the same battery bay and connector. OEM part numbers covered: 0B200-02060000 and C11P1516 (1ICP4/62/129).
- ZU680KL single and dual SIM coverage: Both variants use the same 3.85V rail, identical connector pinout, and the same BMS handshake with the ZU680KL charge IC — one cell fits the full lineup without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a ZU680KL. The BMS reported state-of-charge correctly after one calibration cycle, and the charge IC accepted the cell without triggering fault flags.
- Fuel gauge recalibration on first use: After installation, disable fast charging and complete one full discharge-charge cycle at standard current. The ZU680KL's fuel gauge IC maps its coulomb counter to the new cell's discharge curve during this cycle — skipping it causes the percentage to read against the old curve.
Sudden shutdown at 20–30% on the ZU680KL after a cell swap
The ZU680KL's Snapdragon 652 and its 6-inch FHD display pull high current during combined screen-on and LTE activity. A freshly installed cell with an uncalibrated fuel gauge will report a state-of-charge percentage that no longer matches actual cell voltage under that load. When the cell voltage drops below the BMS protection threshold — typically around 3.2V — during a high-draw moment, the BMS cuts output before the OS reads zero. One full slow discharge-charge cycle forces the coulomb counter to anchor itself to real cell capacity, which eliminates most of these cutoffs.
USB fast charge not activating on the first cycle after replacement
The ZU680KL uses Qualcomm Quick Charge on its USB port, but the charge IC performs a handshake with the BMS before enabling elevated current. On the first cycle with a new cell, the BMS may present an impedance or flag state that causes the charge IC to default to standard 5V/1A charging as a precaution. This is not a fault — it clears after the BMS completes one full cycle and the charge IC confirms stable cell parameters. If fast charging still does not activate after that cycle, check that the cable and adapter both support QC 2.0 or higher, and confirm the adapter negotiates above 5V at the port.