Sony Xperia Z5 Compact Replacement Battery 3.8V 2600mAh

Sony Xperia Z5 Compact (E5823 / E5803) — 3.8V Li-Polymer Replacement Battery

This 3.8V, 2600mAh Li-Polymer battery replaces the original cell in the Sony Xperia Z5 Compact. It fits the E5823 and E5803 variants, along with the S50 and eleven additional model codes sharing the same battery bay and connector. Swap it in when the original cell no longer holds a usable charge or the phone shuts down unexpectedly under load.

• E5823 and E5803 platform fit: These model codes share the same physical battery bay, flex connector pinout, and charge IC communication lines. One cell fits all of them without adapter or modification.
• Bench tested on actual hardware: We ran this cell through the Z5 Compact's charge IC handshake. The BMS accepted the charge cycle without triggering trickle-lock, and voltage held flat across the mid-discharge curve.
• Fuel gauge recalibration on first use: Disable fast charging for the first full discharge-charge cycle after installation. The fuel gauge IC recalibrates its coulomb counter against the new cell's discharge curve. Running a high-current fast charge into an uncalibrated cell skews percentage readings for weeks.

Sudden shutdown at 20–30% on the Z5 Compact after a cell swap

The Z5 Compact's Snapdragon 810 pulls hard during LTE handoffs and screen-on bursts. A new Li-Polymer cell has slightly higher internal impedance until it's cycled. Under that load spike, terminal voltage drops briefly below the shutdown threshold the OS reads — even if the reported percentage says 25%. The phone cuts out to protect the charge IC, not because the cell is faulty. Run two full discharge-charge cycles and the impedance drops enough that voltage no longer clips under peak draw. If shutdown persists past cycle three, check that resting voltage after a full charge reads at least 4.35V.

Battery percentage jumping or resetting to a wrong number after replacement

The fuel gauge IC on the Z5 Compact stores a learned discharge curve from the old cell. When a new cell goes in, that learned map no longer matches actual cell behaviour — so the reported percentage can jump, stall, or read 100% while the phone is nearly flat. This is a coulomb counter calibration issue, not a faulty battery. Force one complete discharge to auto-off, then charge uninterrupted to 100% with fast charging off. After that cycle, the gauge IC resets its reference points against the new cell and percentage tracking stabilises.