Voltage and current capability of FPV drone (on board voltage regulator)
When choosing a PDB, you need to find out the voltages that your components need and make sure that the PDB you choose has a regulator that adapts to these voltages. By doing so, your build will be as clean as possible, both aesthetically and electrically. Typical components that require a specific voltage are FPV cameras, video transmitters (vtx), receivers, and optional add ons such as LEDs.
Note that some receivers need 3.3V, while others need 5V. Some popular vtx can be limited to 5V, others can be limited to 12V input, if you want to use 4S 14.8V flight battery, you must adjust it. It's becoming more and more common that vtx can directly handle the voltage from the flying battery, so it's important to check (click here to see the article about vtx).
Another thing to consider when choosing PDB is the characteristics of the flight controller (FC) you plan to use. Many clubs now include the voltage regulator receiver (Rx). If the FC receiver you want to use provides a regulatory authority, there is no need to have two in your multirotor construction. Also pay attention to what the input voltage of FC is, some FC will now accept battery voltage, and pay attention to adjust the voltage of internal components, which means you may not need to output 5V on your FPV drone distribution board.
The power provided by the voltage regulator on the power distribution box is usually limited by the size of the components used. It is important not to exceed the maximum rated current, otherwise the voltage regulator will overheat and may be damaged. This is very dangerous because it often happens in flight and the components connected to the pressurizer will stop working, which often leads to complete video failure or loss of control.
When selecting a suitable FPV drone distribution board, you will see that the available output voltage is usually accompanied by a number in brackets, that is 12V (2a), which refers to the maximum output current of the voltage regulator. A in capital is ampere, EAC is 1000mA, Ma is ma. You should check the other components you plan to connect to the regulator to see how much power they need, which will often be on the Ma either on the packaging or on the product website. It is a good practice to ensure that the power required by the voltage regulator does not exceed 80% of the rated output power of the regulator.
Vtx is usually the most power consuming component in multi rotor equipment, especially in the case of high power. LEDs also consume a lot of energy, so be sure to check the current required for these components.
Additional functions of FPV drone distribution board
Some manufacturers will offer additional features on their PDB, from built-in LED lighting or buzzers to in car microphones, to capture multi rotor audio for transmission with video back to goggles. Sometimes, choosing a PDB built in with any of these features can reduce the wiring and complexity of your multi rotor, making it easier to build and have fewer potential failure points.
Design of FC / PDB
Recently, more and more manufacturers provide direct built-in flight controller (FC) of PDB, which greatly simplifies the construction of multirotor and allows FC to easily obtain energy consumption information. According to the FC / PDB selected, it may allow you to monitor the power consumption of real-time multirotor, make it easier and more accurate to measure the battery consumption and allow you to optimize your flight time. The size depends on the battery used. Using FC / PDB also means that it is possible to use only one board in the "stack" of multi rotor flight controller. It is very helpful for tight or low profile construction and is becoming more popular in the micro multi rotor market.
I hope this article helps to explain the key points to consider when choosing PDB for your multi rotor build.