Sony Xperia 10 II Replacement Battery SNYSV24 3.85V 3500mAh

Sony Xperia 10 II (XQ-AU42 / XQ-AU51) — 3.85V Li-Polymer Replacement Battery (SNYSV24)

This 3.85V, 3500mAh Li-Polymer battery replaces the OEM SNYSV24 cell in the Sony Xperia 10 II. It fits the XQ-AU42, XQ-AU5, XQ-AU51, and related variants in the Xperia 10 II lineup. Capacity and voltage match factory specifications as listed in the product data above.

• Xperia 10 II variant coverage: The XQ-AU42, XQ-AU5, and XQ-AU51 share the same PCB footprint, connector pitch, and BMS handshake protocol — all accept this cell without hardware modification.
• Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on a XQ-AU51 unit. The BMS accepted the cell on first contact, charge IC registered the correct cell chemistry, and no protection faults were triggered during load testing.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge down to auto-shutoff, then charge to 100% uninterrupted. This lets the coulomb counter recalibrate its state-of-charge model against the new cell's actual discharge curve before high-current charging begins.

Sudden shutdown at 20–30% on the Xperia 10 II after a cell swap

This happens when the fuel gauge IC is still running a state-of-charge model calibrated to the old, degraded cell. The replacement cell has a steeper voltage cliff under modem and display load than the worn cell the IC learned from. When current draw spikes — during a call, GPS lock, or screen-on burst — the new cell's terminal voltage briefly drops below the system cutoff threshold even though the gauge still reads 25–30%. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% forces the coulomb counter to relearn the new cell's curve and eliminates these false cutoffs.

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

After installation, some units default to standard 5V/0.9A trickle charging and ignore USB-PD negotiation entirely on the first charge session. This occurs because the charge IC resets its fast-charge authorisation state when it detects a new cell with an unfamiliar impedance signature. Reboot the phone with the charger connected — the charge IC re-runs its handshake sequence on boot, and USB-PD negotiation typically resumes. If fast charging still does not engage, disconnect, wait 10 seconds, and reconnect the USB-C cable to force a fresh PD contract negotiation from 5V baseline.