To build a 5 inch FPV drone, you need component: frame, motors, electronic speed controllers(ESCs), flight controller(FC), propellers, battery,(4s or 6s Lipo battery with XT60 connector), FPV camera, video transmitter(VTx), antennas, receiver(Rx) and radio transmitter(Tx).

The short answer is that a 5-inch FPV drone typically flies for 3 to 15 minutes on a single battery charge. However, this range is very broad because the actual flight time depends heavily on three main factors: the type of battery you use, your flying style, and the overall weight of your drone.

 A 5-inch FPV drone can typically fly between 130 km/h and 220 km/h. The exact top speed depends heavily on the drone's build, motor power, and whether it's optimized for racing, freestyle, or long-range cruising.

For a quick overview, here are the top speeds from several popular 5-inch drone models:

Most drones are equipped with a low-battery warning system to alert you when the battery power is low. This warning may be displayed in the following forms:

● Visual Indicators: The drone's lights may start flashing or change color to indicate low battery.

● Audible Alerts: Some drones emit a beeping sound or other audible alarms to signal low battery power.

This is safety measurement to prevent the drone from crashing due to a depleted battery.