There are two very good reasons why I don’t produce Power Distribution Boards (PDB) for Red20RC multirotor frames – I don’t have the facilities to do it in house and I don’t think they are a good idea. Let me explain the second reason in more detail…
What do I mean by a PDB?
There are two different components that may be referred to as a PDB.
The first is the small square or circular circuit board that is very simple in nature. It has two circuits – positive and negative – with points for your XT60 power connection in and usually 6 or 8 pairs of pads that output to your ESCs.
The most popular in Mini Quads (and the one I recommend) is the HexTronic mini PDB that fits in the same footprint as a Naze32 style flight controller.
The second type is the custom made PDBs that normally replace one of the plates in a multirotor frame. These can be as simple as an elongated version of the HexTronic PDB but more normally have allocated pads for camera power etc.
In some cases (such as the TBS Discovery) these PDBs can even be expanded to include certain components of circuitry, power filters, regulators and the like.
It’s these second type I’m not so keen on…
What’s the problem then?
The competing Mini Quad manufacturers make a big deal of how strong their frames are and how awesome their high-quality carbon fiber is. Then they go and stick a big slab of floppy G10 fiberglass in the middle with some circuits laminated onto it.
It’s a matter of conductivity. You can’t make a PDB out of carbon fiber as it is conductive, you have to use a non-conductive material like G10 or FR4.
G10 is both heavier and less rigid than decent carbon fiber. Ever notice how the bottom two plates of the Blackout quad are both exactly the same size a shape? I can only speculate but I imagine the second carbon plate has to run full length to support and strengthen the PDB plate.
Okay, so it isn’t the end of the world but when you are trying to save those precious few grams on a racing machine, why take the risk?
By not having a PDB plate on the R220 I can reduce the belly plate to only the areas where it is needed, retaining the strength of the frame and reducing the overall weight.
This is an old one. Incorporating things like BECs, regulators and other components into the PDB plate is a great idea: It tidies up the installation, ensures correct weight distribution, and protects some fragile components from coming loose in flight.
The problem is when one of those components fails. Now, instead of replacing a $5 BEC you need to replace a plate that can cost anything up to $75 (the cost of a new set of TBS Discovery plates).
So why have a PDB then (all the cool kids are doing it)?
- It makes it easier to connect up your electronics correctly with less chance of a short circuit or reversed polarity.
- It makes wiring in the frame neater and looks cool.
- It can make it easier to include such things as regulators, filters etc.
Is there an alternative?
This one here was introduced on Instagram a couple of weeks ago by Hovership and is not yet available (as at the time of writing).
It’s a simple PDB that fits within the same footprint as a Naze32/CC3D. It has pads for up to 6 ESC outputs and you can solder in two Pololu style regulators. Within a 36mm square you can have a modular PDB with direct LiPo to ESC distribution, a stable 5V output for your flight controller and a stable 12v output for your camera and VTx.
Bloody genius! If I ever have the capability to manufacture a PDB, this is the PDB I’ll manufacture – not a heavy, floppy frame plate…