About this replacement
Sony Ericsson Xperia Arc — 3.7V Li-ion Replacement Battery (BA750)
This is a 3.7V, 1500mAh Li-ion replacement battery for the Sony Ericsson Xperia Arc. It fits the LT15a, LT15i, and Anzu variants alongside the core Arc lineup. It slots into the same battery bay as the original BA750 and connects to the same BMS contacts.
- LT15a, LT15i, and Anzu compatibility: These models all run the same 3.7V power rail and use the same four-contact connector layout as the standard Arc. The BMS handshake protocol is identical across the range, so one cell fits all listed variants without hardware modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on an Arc LT15i. The BMS accepted charge without thermal events, and the protection circuit tripped correctly at the low-voltage cutoff threshold before the cell dropped into unsafe territory.
- Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% uninterrupted. The Xperia Arc's fuel gauge IC was calibrated to your old cell's discharge curve — this single cycle gives it accurate data for the new cell before you resume normal use.
Why the Xperia Arc reports wrong battery percentage after a cell swap
The Arc uses a coulomb-counting fuel gauge IC that tracks charge in and out of the original cell over its lifespan. When you fit a new cell, the IC still holds the old degraded cell's reference curve in memory. It maps the new cell's actual charge state against that stale curve, which throws percentage readings off by 10–25% in the mid-range. One full discharge-to-shutdown followed by an uninterrupted charge to 100% forces the IC to write a fresh reference curve. After that cycle, percentage readings stabilise.
Sudden shutdown at 20–30% on the replacement cell
This is a voltage cliff issue, not a capacity problem. Under high load — active LTE, screen at full brightness, or GPS — the cell's internal resistance causes a sharp voltage drop that the Arc's protection circuit reads as a critically low cell. The phone cuts power before the percentage counter catches up. A full recalibration cycle as described above helps, but if shutdowns continue, check that the battery contacts on the phone are clean and making firm contact — dirty contacts add resistance and worsen the sag. Target a resting voltage of 3.85–4.0V after a full charge before putting the phone under load.