About this replacement
Apple iPhone 13 Pro Max — 3.8V Li-Polymer Replacement Battery (103CS / 2203B)
This is a 3.8V, 3500mAh (13.3Wh) lithium-polymer battery for the Apple iPhone 13 Pro Max. It fits models A3083, A3292, A3293, and A3294. It replaces the original cell when capacity has dropped or the battery no longer holds a usable charge.
- A3083 / A3292 / A3293 / A3294 platform fit: These four model numbers cover the same iPhone 13 Pro Max hardware — regional variants sharing the same battery bay dimensions (82.00 × 59.70 × 5.50mm), the same 3.8V nominal voltage rail, and the same connector and BMS handshake protocol. One cell fits all four.
- Bench tested on actual hardware: We ran this cell on iPhone 13 Pro Max units and confirmed the BMS accepted the charge cycle without triggering a protection cutoff. The charge IC negotiated correctly and the cell reached full charge without thermal events.
- Fuel gauge recalibration on first use: After installation, run one complete discharge down to auto-shutdown, then charge uninterrupted to 100% before resuming normal use. This gives the coulomb counter a full reference cycle against the new cell's discharge curve and prevents erratic percentage readings early on.
Sudden shutdown at 20–30% on the iPhone 13 Pro Max after a cell swap
This is a voltage cliff issue, not a capacity fault. Under high-load conditions — active 5G modem, ProMotion display, or GPS — the cell must sustain voltage above the shutdown threshold. A new cell with an uncalibrated fuel gauge IC causes the OS to misread state-of-charge, so the phone cuts power while the reported percentage still shows headroom. The fix is one full discharge-charge reference cycle so the coulomb counter maps the actual voltage-to-capacity curve of the new cell. After that cycle, shutdowns at 20–30% stop in normal use.
iPhone 13 Pro Max not powering on after sitting in storage with the new battery installed
If a battery-equipped phone is stored without use, the cell can self-discharge below 2.5V per cell — the BMS lockout threshold. At that point the BMS disconnects the cell from the charge circuit entirely, and the phone will not respond to a cable or show the charging screen. Connect to a wall adapter (not a computer port) and leave it for 20–30 minutes without pressing any buttons. The charge IC on most iPhones will apply a low-rate pre-charge trickle to bring the cell back above the 2.5V floor before resuming normal charge. If the Apple logo appears, the BMS has re-initialised; let it charge fully before first use.