C11P1608 Asus ZenFone AR Compatible Battery 3.85V 3100mAh

Asus ZenFone AR (ZS571KL / A002A) — 3.85V Li-Polymer Replacement Battery (C11P1608)

This is a 3.85V, 3100mAh Li-Polymer replacement battery for the Asus ZenFone AR. It fits the ZS571KL, A002A, and V570KL variants — all share the same battery bay geometry and BMS handshake protocol. The C11P1608 cell slot drops directly into the standard ZenFone AR battery compartment with no modification.

• ZS571KL / A002A / V570KL compatibility: These three model numbers share an identical battery bay, flex connector pinout, and BMS communication line. The C11P1608 part number covers all three — Asus used the same cell spec across regional variants of this device.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on ZS571KL hardware. The BMS accepted the cell without triggering a fault code, and the protection circuit cut in correctly at the low-voltage threshold — no thermal event, no charging loop.
• Fuel gauge recalibration after swap: After installation, disable fast charging and run one full discharge down to automatic shutdown, then charge uninterrupted to 100%. The ZenFone AR's fuel gauge IC calibrates its coulomb counter against the cell's discharge curve on that first full cycle — skipping this step causes erratic percentage readings.

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

The ZenFone AR runs a Snapdragon 821 paired with a Tango depth-sensing camera array — under combined load, current draw spikes sharply. A new cell with an uncalibrated fuel gauge IC can report 25% remaining while actual cell voltage has already dropped below the 3.4V threshold the BMS uses to trigger shutdown. This is a voltage cliff, not a defective cell. One full uninterrupted discharge-charge cycle lets the coulomb counter establish an accurate state-of-charge baseline against the new cell's actual capacity curve. After that cycle, the shutdowns stop.

USB charging not starting after deep discharge in storage

Li-Polymer cells stored below 2.5V per cell trigger a BMS lockout — the protection circuit opens and blocks charge current to prevent damage to the degraded cell. A standard charger will show no charging indicator and the phone will not power on. To recover, apply a low-current trickle source — a USB port capped at 500mA — for 20 to 30 minutes before attempting a normal charge cycle. Once cell voltage climbs above 2.8V, the BMS closes the circuit and normal charging resumes.