Verizon F350 Li-ion Replacement Battery 3.7V 830mAh

Verizon F350 — 3.7V Li-ion Replacement Battery (Li3708T42P3h453756)

This 3.7V, 830mAh Li-ion cell is a direct replacement for the Verizon F350 smartphone. It fits the original battery bay and restores power to calls, messaging, and on-device applications. Capacity figures are taken from the product data: 830mAh / 3.07Wh.

• F350 battery bay compatibility: The F350 uses a compact 44.63 × 37.56 × 5.44 mm cell at 3.7V nominal. This replacement matches that form factor and voltage rail exactly. OEM part numbers Li3708T42P3h453756, Li3709T42P3h453756, and Li3707T42P3h443747 all cross to this cell.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the F350 platform. The BMS accepted charge current without flagging an overvoltage fault, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before the phone starts applying fast-charge current against an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the F350 after a cell swap

The F350's fuel gauge IC was calibrated against the original cell's internal resistance and discharge curve. A new cell has different impedance, so the IC's voltage model diverges from reality under load — especially when the modem fires a transmit burst or the screen hits full brightness. The phone reads 25% but the cell voltage drops below the shutdown threshold under that load spike. One full uninterrupted discharge cycle from 100% to automatic cutoff resets the coulomb counter and corrects this. After that cycle, charge to 100% before normal use.

Phone warm near the battery compartment on first charge

A new Li-ion cell has slightly higher internal impedance than a broken-in cell, which means the charge IC dissipates more heat during the constant-current phase of the first charge. This is normal and typically resolves after two or three full cycles as the cell's impedance settles. If the device stays warm beyond the first two charges, check that the back cover is seated fully — trapped air against the cell amplifies heat buildup. Surface temperature above 45°C warrants removing the phone from charge until it cools.