Apple iPhone 14 Pro Max A2830 Replacement Battery 3.87V 4300mAh

Apple iPhone 14 Pro Max — 3.87V Li-Polymer Replacement Battery (A2830)

This 3.87V, 4300mAh Li-Polymer battery replaces the original A2830 cell inside the iPhone 14 Pro Max. It fits the internal battery slot directly and covers the full device — processor load, display, modem, and camera systems. Capacity figure matches the product specification: 4300mAh / 16.64Wh.

• iPhone 14 Pro Max cell compatibility: The 14 Pro Max uses a single Li-Polymer pouch cell on a 3.87V nominal rail with a proprietary BMS handshake. This A2830 replacement matches that voltage rail and connector footprint exactly — no adapter, no re-pinning.
• Bench tested on actual hardware: We ran the A2830 replacement through full charge cycles on a 14 Pro Max unit. The BMS accepted the cell without fault codes, and the charge IC stepped through trickle, CC, and CV phases cleanly with no cutoff errors.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% on a standard 5W or 12W adapter. This gives the coulomb counter a clean reference cycle before high-current USB-PD charging begins.

Why the iPhone 14 Pro Max reports wrong battery percentage after a cell swap

iOS uses a fuel gauge IC that tracks capacity by counting charge in and out of the original cell's discharge curve. When a new cell goes in, that stored curve no longer matches the physical cell sitting in the device. The gauge keeps using the old reference, so it can show 40% when the cell is actually near depletion — or 100% well before the cell is full. One full discharge-to-shutdown followed by a full uninterrupted charge resets the coulomb counter against the new cell. After that single cycle, percentage reporting tightens up significantly.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC is still calibrated to the old degraded cell and hasn't mapped the new cell's voltage cliff correctly. Under modem burst load or ProMotion display draw, the cell voltage drops sharply at a state-of-charge the gauge still reads as safe — the protection circuit trips and the phone cuts off. It is not a faulty cell. Run one full discharge cycle without fast charging, letting the phone reach automatic low-battery shutdown at its own pace. After that cycle, the gauge recalibrates the cliff point to roughly 3.0–3.1V under load and the premature shutdowns stop.