About this replacement
Sony Ericsson Xperia Z1 Mini — 3.8V Li-Polymer Replacement Battery (LIS1529ERPC)
This 3.8V, 2300mAh Li-Polymer cell replaces the original battery in the Sony Ericsson Xperia Z1 Mini, SO-02F, Amami, Maki, and Xperia Z1s. It matches OEM part number LIS1529ERPC and fits the same 98.49 x 54.29 x 3.79mm footprint as the factory cell. Capacity is rated at 8.74Wh.
- Xperia Z1 Mini platform fit: The Z1 Mini, SO-02F, and Maki variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol — all run on the same LIS1529ERPC cell, so this replacement covers the full model group without modification.
- Bench tested on actual hardware: We cycled this cell through charge, full load discharge, and a simulated modem-plus-screen draw scenario. The BMS held voltage above the cutoff threshold and the fuel gauge IC accepted the cell without throwing a fault flag.
- Fuel gauge recalibration on first use: After installation, run one full discharge down to auto-shutdown, then charge uninterrupted to 100% with fast charging disabled. This lets the coulomb counter map the new cell's discharge curve before high-current charging begins against an uncalibrated fuel gauge.
Sudden shutdown at 20–30% on the Xperia Z1 Mini after a cell swap
The Z1 Mini's fuel gauge IC retains the discharge curve of the old, degraded cell. When a new cell is installed, the IC underestimates how much voltage remains at mid-charge states. Under screen-on plus LTE modem load, the phone hits a voltage sag the IC misreads as near-empty and triggers an emergency shutdown. The fix is one full unconditioned discharge-to-shutdown followed by a full uninterrupted charge. After that single cycle, the coulomb counter recalibrates and the percentage readings stabilise above 3.6V.
Phone feels warm near the battery compartment during the first charge cycle
A fresh high-impedance Li-Polymer cell produces more heat than a broken-in one because the charge IC pushes current into a cell it hasn't profiled yet. Internal resistance on a new cell is measurably higher in the first few cycles and converts more charge current to heat. This is normal and decreases after two to three full cycles as the electrolyte settles. If warmth continues past the third charge, check that the phone isn't charging inside a case — trapped heat above 40°C will cause the charge IC to throttle current and extend charge time.