About this replacement
Apple iPhone 7 — 3.8V Li-Polymer 2200mAh Replacement Battery (616-00255)
This 3.8V Li-Polymer battery at 2200mAh (8.36Wh) is a direct cell replacement for the Apple iPhone 7 and iPhone 7 4.7" (A1660, A1780 and related variants). It fits the same footprint as the original at 94.30 × 39.46 × 3.45mm. Install it when the original cell has degraded, won't hold charge, or triggers unexpected shutdowns.
- iPhone 7 model compatibility: The A1660, A1778, and A1780 variants all share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell fits every regional iPhone 7 SKU without modification.
- Bench tested on actual hardware: We installed this cell on an iPhone 7 A1778 and ran it through a full discharge-charge cycle. The BMS negotiated correctly with the charge IC, accepted current without thermal event, and the OS reported accurate state-of-charge by end of the first full cycle.
- First-cycle fuel gauge reset: After installation, disable fast charging and run one complete discharge down to automatic shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC a clean discharge curve to map against the new cell — skipping this step is why percentage readings jump erratically in the first few days.
Sudden shutdown at 20–30% on a replacement iPhone 7 cell
This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. When the iPhone 7 hits peak modem load — during a call or LTE data burst — the new cell's actual voltage drops below the threshold the IC expects at that reported percentage. iOS treats the voltage cliff as empty and cuts power to protect the cell. One full discharge-charge cycle recalibrates the coulomb counter against the new cell. After that cycle, shutdowns at false-high percentages stop.
Device won't power on after replacement battery sat in storage
Li-Polymer cells self-discharge in storage, and if voltage drops below approximately 2.5V per cell, the BMS trips into lockout to prevent damage. The iPhone will show no response — no Apple logo, no charge indicator — when you first connect a cable. Connect to a wall adapter (not a PC USB port) and leave it for 20–30 minutes without interruption. The charge IC trickle-charges the cell back above the BMS unlock threshold, typically around 3.0V, before resuming normal charge current. Once the battery icon appears on screen, the BMS has cleared lockout.