Asus ZenFone 6 2019 C11P1806 Replacement Battery 3.85V 4600mAh

Asus ZenFone 6 2019 (ZS630KL) — 3.85V Li-Polymer Replacement Battery (C11P1806)

This is a 3.85V, 4600mAh Li-Polymer cell built to fit the Asus ZenFone 6 2019, ZenFone 6 2019 Global, ZenFone 6 2019 Dual SIM, and ZS630KL. It replaces OEM part number C11P1806 (also listed as 1ICP5/65/87). If your original cell is swelling, failing to hold charge, or causing unexpected shutdowns, this cell is a direct physical and electrical match at 17.71Wh.

• ZS630KL platform fit: The ZenFone 6 2019 lineup — Global, standard, and Dual SIM variants — all share the same motherboard revision and battery connector. The BMS handshake, voltage rail at 3.85V nominal, and physical footprint (87.18 x 64.50 x 4.64mm) are identical across these variants, so one cell covers the full range.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a ZS630KL unit. The BMS accepted the cell without error flags, charge IC negotiated correctly, and the fuel gauge IC began tracking state-of-charge from the first cycle without manual reset.
• First-cycle fast charge tip: On first use after installation, disable fast charging and complete one full discharge-to-charge cycle at standard rate. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current fast charging pushes into an uncalibrated state.

Sudden shutdown at 20–30% on the ZenFone 6 2019 after a cell swap

This is a voltage cliff issue, not a capacity defect. The ZenFone 6 2019's modem and flip-camera motor together draw sharp current spikes. If the fuel gauge IC is still calibrated to the old cell's discharge curve, it misreads remaining capacity and the phone shuts down before the cell is actually empty. The fix is one full uninterrupted discharge from 100% down to automatic shutdown, then a full charge without interruption. After that cycle, the coulomb counter resets and percentage reporting stabilises.

USB-PD or fast charge not accepted on the first cycle after replacement

A new high-impedance cell can cause the charge IC to fall back to standard 5V charging on the first connection — the ZenFone 6 2019's charge controller is conservative when cell impedance reads outside its expected range for a "known" cell. This is not a fault in the replacement cell. Complete one full standard-rate charge first, then reconnect your fast charger. By the second cycle the charge IC accepts the fast-charge handshake and negotiates correctly at the higher voltage.