About this replacement
Apple iPhone 6 Plus — 3.82V Li-Polymer Replacement Battery (616-0765)
This 3.82V, 3300mAh (12.61Wh) lithium-polymer cell replaces the original battery in the Apple iPhone 6 Plus. It fits the 5.5-inch model across variants A1522, A1593, and related revisions. Install it when the original cell no longer holds charge or causes unexpected shutdowns.
- iPhone 6 Plus compatibility (A1522 / A1593): These model numbers share the same logic board connector, physical cell envelope (119.30 × 48.40 × 3.60mm), and BMS handshake protocol. The 3.82V nominal rail matches what the iPhone 6 Plus charge IC expects — no adapter or modification needed.
- Bench tested on actual hardware: We ran this cell through a full discharge-charge cycle on an iPhone 6 Plus logic board. The BMS communicated correctly with the charge IC, and charge termination triggered at the expected 4.35V cutoff without manual override.
- Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the coulomb counter one clean cycle to map the new cell's discharge curve before you return to normal use.
Why the iPhone 6 Plus reports wrong battery percentage after a cell swap
The fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The iPhone then reads state-of-charge off the wrong map, so the displayed percentage drifts away from reality. One full discharge-to-shutdown followed by an uninterrupted charge to 100% resets the coulomb counter and aligns it to the new cell.
Sudden shutdown at 20–30% on the replacement cell
This happens when the cell voltage drops sharply under high-current load — modem transmit bursts and screen-on draw can pull enough current to drag voltage below the BMS cutoff threshold, even when the gauge still shows charge remaining. The original fuel gauge calibration predicts a gentler slope, so it doesn't warn iOS in time. Run two full recalibration cycles and the shutoffs typically stop. If they continue past two cycles, check that cell-to-connector solder tabs are fully seated — a high-contact resistance point causes the same voltage cliff at the connector before the cell itself is depleted.