Fly IQ4410 Replacement Battery 3.7V 1600mAh Li-ion

Fly IQ4410 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1600mAh Li-ion replacement battery for the Fly IQ4410 smartphone. It slots into the original battery bay and reconnects to the phone's charge IC and fuel gauge circuit. Capacity is 1600mAh (5.92Wh), matching the original cell specification.

• IQ4410 platform fit: The IQ4410 uses a fixed-contact rectangular cell with a three-pad connector that feeds both the charge IC and the coulomb counter. This cell matches that connector layout and the voltage window the phone's BMS expects — 3.0V cutoff to 4.2V full charge.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the IQ4410 platform. The BMS accepted the cell on first connection, charge termination triggered correctly at 4.2V, and the fuel gauge began tracking state of charge from the first cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the OS begins reporting percentage from a calibrated baseline.

Why the IQ4410 reports wrong battery percentage after a cell swap

The IQ4410 uses a fuel gauge IC that tracks charge state by counting coulombs against a stored discharge curve from the previous cell. When a new cell goes in, that stored curve no longer matches the new cell's actual voltage-to-capacity profile. The gauge reads the new cell's voltage and maps it to the old curve, producing percentage figures that are off — sometimes by 15–20 points. One full discharge down to automatic cutoff, followed by a full charge to 4.2V, resets the reference curve and brings the percentage display back in line.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem, display, or a background process draws a short current spike the cell cannot sustain without the terminal voltage dropping below the BMS cutoff threshold. A fresh cell with an uncalibrated fuel gauge compounds this — the phone thinks it has 25% remaining while the actual cell voltage has already sagged to near 3.0V under load. The BMS trips and the phone shuts off hard. Run the recalibration cycle first: discharge fully until the phone powers off on its own, then charge uninterrupted to 4.2V before normal use.