Fly IQ4516 Replacement Battery 3.8V 2050mAh Li-Polymer

Fly IQ4516 Tornado — 3.8V Li-Polymer Replacement Battery

This 3.8V, 2050mAh Li-Polymer cell replaces the original battery in the Fly IQ4516 Tornado smartphone. It fits the battery bay directly and connects to the same charge IC and fuel gauge system the phone shipped with. Capacity is 2050mAh at 7.79Wh — identical to the factory specification.

• IQ4516 Tornado platform fit: Both model name variants — IQ4516 and Tornado — share the same PCB layout, connector pitch, and BMS handshake protocol. The cell dimensions are 81.40 × 60.26 × 2.86mm, matching the original cavity without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the IQ4516 platform. The BMS accepted the cell without a fault flag, and the charge IC completed a full constant-current/constant-voltage charge sequence to 4.35V cutoff.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC build an accurate discharge curve against the new cell before the charge IC begins pushing higher current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Fly IQ4516 after a cell swap

The IQ4516 fuel gauge IC retains the discharge curve it learned from the old, degraded cell. When the new cell is installed, the IC underestimates how much charge remains at mid-range state-of-charge. Under modem or display load, voltage sags faster than the IC predicts, and the phone shuts off to protect the cell — even though the percentage shown was 25% or higher. One full discharge cycle from 100% to automatic shutdown, followed by a full charge without interruption, forces the coulomb counter to recalibrate. After that cycle, percentage readings stabilise and premature shutdowns stop.

Phone warm near the battery during the first few charges

A new Li-Polymer cell has higher internal impedance than a worn cell, and the charge IC on the IQ4516 initially pushes current calibrated to a lower-impedance load. The result is slightly elevated heat at the battery contact area during the first two or three charge sessions. This is normal — internal impedance drops as the cell forms through early cycles. If the phone becomes hot to the touch rather than warm, interrupt the charge and check the USB cable and port for debris or corrosion before resuming.