About this replacement
Apple iPhone 6 Plus — 3.82V Li-Polymer Replacement Battery (616-0765)
This is a 3.82V, 2900mAh Li-Polymer battery for the Apple iPhone 6 Plus (A1522, A1593). It fits the 5.5-inch model only — not the standard iPhone 6. Swap it when the original cell no longer holds a charge or causes unexpected shutdowns.
- iPhone 6 Plus compatibility: The A1522 and A1593 variants share the same 3.82V battery rail, connector pitch, and BMS handshake protocol. This cell matches those electrical requirements exactly, including the NTC thermistor line the charge IC monitors during every session.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on an iPhone 6 Plus board. The charge IC accepted the BMS handshake without fault codes, and the fuel gauge IC tracked state-of-charge across the complete discharge curve without dropping out.
- Fuel gauge recalibration on first install: After fitting this cell, disable fast charging and run one complete discharge down to auto-shutoff, then charge uninterrupted to 100%. This gives the coulomb counter a clean reference cycle before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the iPhone 6 Plus after a cell swap
This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. The replacement cell has a different internal resistance profile, so voltage drops faster under modem or display load than the IC expects. When terminal voltage falls below the shutdown threshold — even briefly — the phone cuts power regardless of the percentage shown. One full discharge-to-shutoff cycle followed by an uninterrupted charge lets the coulomb counter remap its curve to the new cell.
Phone warm near the battery compartment during first few charges
A new Li-Polymer cell has higher internal impedance than a broken-in one. The charge IC pushes constant current into higher resistance, and that energy difference becomes heat at the cell surface. This is normal for the first three to five cycles and tapers off as the cell's impedance settles. If the phone stays warm beyond the fifth charge or the back panel becomes uncomfortable to hold, check that no adhesive is trapping heat between the cell and the rear case.