About this replacement
Apple iPhone XR — 3.8V Li-Polymer Replacement Battery (616-00471)
This 3.8V, 2900mAh Li-Polymer cell replaces the original battery in the Apple iPhone XR, including variants A2105, A2106, and A2108. It fits the same footprint as the OEM unit at 101.34 × 44.32 × 4.16mm and connects to the same flex cable and BMS on the logic board. Install it when the original cell can no longer hold charge through a full day of use.
- iPhone XR A-series variant coverage: The A2105, A2106, and A2108 share an identical battery bay, connector pinout, and BMS handshake protocol. One cell fits all three regional variants without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on an iPhone XR logic board. The BMS accepted the cell, reported voltage correctly to iOS, and held the charge IC in CC/CV mode without tripping overcurrent protection.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.
Why the iPhone XR reports wrong battery percentage after a cell swap
The iPhone XR uses a coulomb-counting fuel gauge IC that tracks charge by measuring current in and out over time. When you install a new cell, the IC still holds the discharge curve it built around the old, degraded cell. It cannot know the new cell's actual capacity until it maps a full cycle. Until that calibration happens, iOS will show percentage figures that do not match real remaining charge — often reading 30% while the phone still has significant capacity left, or dropping suddenly near the end.
Sudden shutdown at 20–30% on the replacement cell
This happens when the fuel gauge IC is still calibrated to the old cell and the phone hits a high-current load spike — typically the modem during a call or the display at full brightness. The new cell can sustain the load, but the IC reads voltage against the wrong curve and triggers a low-voltage shutdown before the cell is actually exhausted. Run one full discharge down to automatic power-off, then charge uninterrupted to 100%. After that cycle, the coulomb counter resets its reference and the shutdowns stop.