Components Guide | PDBs under the magnifying glass

Posted by Jagdish Prajapat on October 20th, 2018

Today we will follow up on the article about LiPo batteries. Let's go back one by one the components of the "strong current" part (which can also be called "power" part) of our dear racers by approaching the universe of PDB.

As an indication, the strong current portion, involves the power components in which pass a high electrical intensity. In our quads, it's the PDB, the ESCs and the motors (everything that receives its power directly from the LiPo). All the rest can be considered as belonging to the family of "weak currents" (FPV, VTX, FC, LED's ...). We call low current all that is low voltage power supply (the 5 volts of your flight controller for example) and the signals (video, ESC control ...).

What is a PDB?

A PDB (Power Distribution Board) is as its name suggests a power distribution board. It consists of different pads on which you can solder the wires of the components to be electrically connected. These pads are connected inside the circuit board so as to distribute electricity to the other connections concerned. Thus all the masses of the PDB are connected to that of the LiPo for example. This is not always the case of the +, but we will see the reason for this phenomenon a little lower in this article.

The PDB allows you to properly distribute the power from the LiPo to the other components of the machine. The use of a PDB facilitates assembly and repairs. Each device is soldered independently on the circuit, it is subsequently easy to add or remove.

Technical characteristics

The main technical characteristics of a distribution board are the supported voltage range and the maximum permissible current. These values ​​are important because they condition the batteries you can use, but also how many amperes your configuration will consume safely! Logically found units already seen in the article about LiPo's batteries, if they are not familiar to you, I invite you to take a look at the article via this link .

Voltage

Most of the time, this indication is not given in volts but in "S". In S will you say to me? Yes, you read correctly, this is the same unit we saw in the LiPo article. The same one that reveals the number of elements contained in a pack, and therefore its ... Tension!

PDBs with indications similar to "2-4S" will be found to support voltages of 7.4 to 14.8 volts. I specify that these voltages are rated voltages, a charged 4S battery will have 16,8 volts on its terminals and will not damage a PDB provided to operate in 4S.

The maximum current

In the same way that the circuit has a maximum operating voltage, it also includes a maximum tolerated current. It is expressed as any current in amperes and should be consistent with the configuration of your machine. If your engines pull 140 Amps of gas, and your PDB can only handle a maximum of 100 Amps, you simply burn out the circuit of the distribution plate. This kind of failure has only one consequence and not least: your quad 'will no longer have any power! What happens when a racer has no juice? He falls like a stone! For your safety, that of potential spectators, and that of your machine, it is therefore important to choose a PDB that can withstand a current higher than what your machine will consume.

Do not worry, most PDBs on the market offer comfortable current thresholds. This is most of the time not a blocking criterion for the purchase of this type of material, but it is still important to keep this information in mind in order to have components with consistent characteristics.

Size and shape

The PDB is a component that takes place on our machines in the same place as the flight controller. It is systematically placed under the latter to facilitate connections between the two plates. Therefore, a PDB will share the same physical characteristics as an FC, ie a square shape, mounting holes arranged at the four corners with a spacing of 20 or 30.5mm.