Building your own power distribution board with integrated voltage regulation is actually more straightforward than most pilots think, though you need to respect basic electrical principles to avoid creating a fire hazard or frying expensive components.
Start with your base design. I use EasyEDA or KiCad for the PCB layout. The main battery input traces need to handle significant current, so plan for at least 2oz copper weight on a standard thickness board. For a typical 5-inch racing quad pulling 150 amps peak, you want those main power traces at least 8mm wide. The individual ESC pads can be narrower, around 3-4mm each, since the current splits four ways.
For the voltage regulation section, choose your buck converter chips carefully. I've had excellent results with the TPS54331 for 5V output at 3 amps, which handles most FPV cameras and VTX needs. If you're running power-hungry accessories like LED strips or a GoPro, step up to something like the LM2596 module rated for 5 amps continuous. For 12V output, which you might need for certain VTX systems or older camera setups, the same LM2596 works well but you'll adjust the feedback resistor values accordingly.
The critical part is your filtering capacitors. Place a 470uF to 1000uF low-ESR electrolytic capacitor right at the battery input to smooth voltage spikes during throttle punches. Then add 100uF capacitors at each regulator output, plus 10uF ceramic caps as close as possible to the regulator IC pins. This three-stage filtering eliminates the noise that causes video static.
Heat dissipation matters more than people realize. Those buck converters can get hot when dropping from 16V battery voltage down to 5V while supplying 2-3 amps. I always include a ground pour on both PCB layers and add thermal vias connecting them. If possible, mount a small heatsink or use the frame itself as a heat spreader.
For actual construction, have your PCB manufactured by JLCPCB or similar for about fifteen dollars including shipping. Hand-soldering the SMD regulators takes practice but is doable with a fine-tip iron and flux. The hardest part is the initial alignment. Use solder paste and a hot plate if you're doing multiple boards.
Testing is crucial before installation. Apply power through a current-limited bench supply set to 2 amps maximum initially. Verify your 5V and 12V outputs with a multimeter under no load, then progressively add load using resistors or actual accessories while monitoring for voltage sag and excessive heat.
