Asus ZenFone 3 Max Compatible Battery C11P1611 3.85V 4100mAh

Asus ZenFone 3 Max 5.2 — 3.85V Li-Polymer Replacement Battery (C11P1611)

This 3.85V, 4100mAh Li-Polymer cell replaces the original C11P1611 battery in the Asus ZenFone 3 Max 5.2 (ZC520TL), including Dual SIM and Global variants. It fits the same cavity, uses the same connector, and works with the phone's onboard charge IC without modification. Capacity matches OEM spec at 15.79Wh.

• ZC520TL and ZenFone 3 Max 5.2 variants: All listed models share the same battery bay dimensions, the same flex connector pinout, and the same BMS handshake requirements. One cell covers the full ZC520TL range without adapter or modification.
• Bench tested on actual hardware: We cycled this cell on a ZC520TL unit and confirmed the BMS accepted charge on the first connection, the charge IC reached full termination voltage, and no thermal events occurred across three full charge cycles.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the coulomb counter a clean reference curve for the new cell before fast-charge current is applied.

Why the ZC520TL reports wrong battery percentage after a cell swap

The ZenFone 3 Max 5.2 uses a coulomb-counting fuel gauge IC that builds its discharge model from the previous cell's chemistry data. When a new cell goes in, that stored model no longer matches the actual charge curve of the replacement. The phone reads voltage and maps it against the old curve, so percentages appear higher or lower than reality. One full uninterrupted discharge-to-shutdown followed by a full charge resets the reference data and brings the percentage display back into alignment.

Sudden shutdown at 20–30% remaining on the ZC520TL

This is a voltage-cliff failure, not a capacity failure. Under modem load or screen-on draw, the cell voltage drops faster than the fuel gauge predicts, crossing the BMS low-voltage cutoff before the reported percentage reaches zero. It happens most often when the fuel gauge IC is still calibrated to a degraded old cell curve. Run one full recalibration cycle as described above. If shutdowns continue past that point, check that the replacement cell connector is fully seated — a partial connection raises internal resistance and accelerates the voltage drop under load.