About this replacement
Apple iPhone 7 — 3.8V Li-Polymer Replacement Battery (616-00255)
This 3.8V, 1960mAh lithium-polymer cell replaces the original battery in the Apple iPhone 7, including A1660, A1780, and the 4.7" variants. It fits the same footprint as the OEM cell at 93.00 × 37.70 × 3.10mm and connects via the standard five-pin flex connector. Swap it when the original cell can no longer hold voltage under screen or modem load.
- iPhone 7 platform fitment: The A1660, A1778, and A1780 variants all share the same battery bay dimensions and connector pinout. One replacement cell covers all of them — no adapter or connector modification needed.
- Bench tested on actual hardware: We cycled this cell on an iPhone 7 A1778. The BMS accepted the charge handshake on the first connection, voltage held steady through a full discharge, and the charge IC did not flag a fault at any point in the cycle.
- Fuel gauge recalibration on first use: After installing this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before enabling fast charging. This gives the coulomb counter one full reference cycle against the new cell's discharge curve — skip it and the percentage readout will drift.
Sudden shutdown at 20–30% on a replacement iPhone 7 cell
This is a voltage cliff problem, not a capacity problem. When the modem transmits or the screen runs at full brightness, current draw spikes sharply. If the fuel gauge IC is still calibrated to the old cell's discharge curve, it misreads state-of-charge — the phone thinks it has 25% left, but the cell voltage has already dropped below the shutdown threshold under load. The BMS cuts power to protect the cell. One full discharge-to-shutdown cycle followed by an uninterrupted charge to 100% resets the coulomb counter reference point and eliminates the premature cutoff.
iPhone 7 not powering on after the replacement cell sat in storage
Li-polymer cells self-discharge in storage, and if this battery sat long enough to drop below approximately 2.5V, the BMS will have entered a lockout state to prevent further discharge damage. The phone will show no response — no Apple logo, no charge indicator. Connect it to a charger and leave it for 15–20 minutes before attempting to power on; the charge IC trickle-charges the cell at low current until voltage climbs back above the BMS re-enable threshold of around 2.9V. If the charge indicator still does not appear after 30 minutes, try a different Lightning cable and adapter to rule out a current-delivery fault before assuming the cell is unrecoverable.