Wiring

[wolph42]

I have read numerous (new) build pages and written one myself as well (see link in sig) and the one thing that is either not mentioned at all or mentioned in one word is 'wiring'.

Can anyone tell me more about the wiring? Preferably in relation to my own build: Multi Rotor - My Parts

Questions I can think off:
1. where best to buy them (online preferably)
2. are there any 'standard packages' to be found online (e.g. a bag with lots of wires and connectors typically used for multicopter builds)
3. what type of wiring do I need (diameter, material, colors, length)
4. what kind of plugs are generally used (types sizes amount etc)
5. what comes with wires and what not (e.g. ESC's are usually with wires and banana(?) plugs)
6. do I need to solder them (and what kind of solder is preferred)
7. do I need special tools/equipment (like e.g. a crimper is required for rj45 plugs)
8. any general advice in this area, pointers tricks etc.

Point is, obviously we have an electronics shop in town and Im sure they have all I need... they are also roughly 10x more expensive then online shops. So I don't mind buying stuff there occasionally but not bulk. Also IF special equipment/tools are required it possible that they don't have it. And since ordering something (from my location) usually takes about 2 weeks on average I prefer to get it right in one go.

Thank you!

EDIT: as long as I can edit this post Ill update also my findings. I initially couldn't find anything about wiring, but I just found this:
- http://oddcopter.com/2012/04/13/quadcopter-wiring/ (which helps quite a bit)

 

[SleepyC]

Looking at that diagram from oddcopter that might be ok for a sport quad or just a first quad, but there are many flaws for a commercial rig. Using bullet connectors on the power leads is a problem waiting to happen.

 

[wolph42]

care to elaborate? As in what *is* good practice?

 

[Motopreserve]

I would suggest either wiring your own "squid" for power, or if you really want to go for a PDB, make sure you buy a quality one that is rated for your requirements/draw.

Also, in terms of "special tools," I would suggest an adjustable soldering station if you don't already have one. I have the older Weller analog version, but the new ones are digital. Takes the guesswork out of your heat settings.

 

[SoCal Blur]

Looking at that diagram from oddcopter that might be ok for a sport quad or just a first quad, but there are many flaws for a commercial rig. Using bullet connectors on the power leads is a problem waiting to happen.

I have to disagree with you. In commercial operations, the ability to replace parts quickly is important and bullet connectors make that possible. The way to prevent problems is to heat shrink over the connectors once you have the final connections done. This will hold them together and prevent accidental separation. Then, if you need to replace a component, a razor blade or exacto can cut through the heat shrink to allow separation of the bullet connectors.

care to elaborate? As in what *is* good practice?

The MOST reliable method is as SleepyC illuded to is soldering all connections directly with no connectors. However, as I mentioned above, its not necessarily the most practical.

I would suggest either wiring your own "squid" for power, or if you really want to go for a PDB, make sure you buy a quality one that is rated for your requirements/draw.

Also, in terms of "special tools," I would suggest an adjustable soldering station if you don't already have one. I have the older Weller analog version, but the new ones are digital. Takes the guesswork out of your heat settings.

As Motopreserve mentioned, a variable temperature soldering station is best. You will also need a heat gun for the heat shrink tubing.

When you buy wire be sure to get the silicon insulation wire. It is very flexible and is less likely to break. As far as gauges, I use 10 AWG for my battery to PDB connections, 14 AWG for PDB to ESCs and ESCs to Motors. Larger gauge is always better when it come to electricity flow... because larger sizes have less resistance. However, it does add a bit more weight, but I think the safety of larger gauges outweighs the negative of the additional weight.

Since you're in Nederland (my home country) you can order your wire from places like HobbyKing. I order mine from BuddyRC here in the states. The stuff is not cheap but it's much less expensive online than if you were to buy it at a local hobby shop.

Motopreserve's recommendation of making a Squid vs. a PDB is the most reliable. However when it comes to larger aircraft such as Hexacopters and Octocopters, it isn't the cleanest or easiest way to go because it will get very bulky and you have a greater chance of not having strong solder connections. I use a 300Amp PDB which consists of two separate plates for each polarity. That works well for my Octo.

Also, when it comes to solder, I recommend that you use the leaded version (60/40). Non leaded solder is a pain to work with and requires higher temperatures, and in my opinion, isn't as strong as leaded solder.

 

[wolph42]

thanks. So its ONLY the power distribution for which I need to check the cables. I know the F550 has a built in PDB so that is covered. Anything else?

 

[jes1111]

what *is* good practice?

Sounds like you're willing and ready to do the job properly. Without wishing at all to sound condescending, my advice to you would be first to learn about electricity (resistance, amps, watts, etc.). You are entirely right that this subject is normally "skipped over" - the principal interest/excitement/focus is on the electronic/electrical components being connected together, rarely on the wire and connectors being used to do so. It's a chore: the unsexy, uninteresting part of the build.

The reality, of course, is that it is a common cause of crashes - poor wire sizing, poor connectors, poor soldering. As such, you shouldn't be taking other people's recommendations on sizes, types, techniques, etc. but rather making those decisions yourself from an informed position. What current will be passing through this wire? What is it's resistance per metre, therefore what will be the voltage drop and power consumption?

In that blog you linked to, Oddcopter says he used 18AWG wire to make his spider because with that size he could fit 4 of them into the back of an EC5 connector! He may be using the right size, but for a really wrong reason! And, as Sleepy points out, bullets are a bad choice: they tend to disconnect themselves under vibration. If you do use them you should heatshrink over them so that they cannot come apart (which makes them a pain anyway).

One problem that is rarely mentioned is the vulnerability of soldered wires in a vibration-rich environment. When you solder a wire to a connector (or to a PDB or ESC) a certain amount of solder will travel up inside the insulation (called "wicking"). The longer you leave the heat applied, the further it will travel. In use, the transition point between solder and the copper conductors is a severe "weak spot" which is highly susceptible to fracturing under vibration. To mitigate this risk, such a joint should always be supported beyond this interface point: as a minimum, one or two layers of heatshrink - much better would be a physical "strap down" point. Commercial aircraft wiring and automotive wiring both follow this principle, yet it is widely ignored in our multirotor world.

Consider, too, the benefit of crimping versus soldering. There are many advantages - look into "Anderson Powerpole" connectors. Connectors with positive locking is another feature to ponder. Positive/negative power wires should always be twisted together to minimise interference.

A final thought: the RC retail business is full of poorly designed products (usually at absurdly inflated prices) that are "designed", often, just to be different from whatever else is being sold. You should disregard widespread availability and popularity - they are not reliable indicators of quality or suitability! Much better to look at other industries and see what components/techniques they use (and why).

 

[Motopreserve]

Jes is right on. The understanding and knowledge is what will give you the ability to wire up the multirotor correctly, and in turn the confidence to fly it. I spent far more time critiquing my wiring than I did my component choices (which was not itself insignificant). Then once I got airborne I had a little more time to worry about flying than whether the craft would drop from the sky due to cold solder points or bad flow/calculations.

One thing that helps me is to diagram the wiring with routing and components on paper before I ever touch iron to wire. I do it in Illustrator because my handwriting would prove useless . This way you can get a feel for the layout and what should go where.

Ive just begun to make the switch to Anderson connectors (XT-60 until now). Not cheap, but not bad in the scheme of things. I may have been turned onto them by one of your posts Jes. Thanks! Also, as SoCal said: silicone wire is much easier to deal with and provides some flexibility, as long as it's quality.

Kudos for digging deeper on this critical topic. As Jes mentioned, many skip over it for the more sexy components of a build...

 

[wolph42]

Sounds like you're willing and ready to do the job properly. Without wishing at all to sound condescending, my advice to you would be first to learn about electricity (resistance, amps, watts, etc.). You are entirely right that this subject is normally "skipped over" - the principal interest/excitement/focus is on the electronic/electrical components being connected together, rarely on the wire and connectors being used to do so. It's a chore: the unsexy, uninteresting part of the build.

The reality, of course, is that it is a common cause of crashes - poor wire sizing, poor connectors, poor soldering. As such, you shouldn't be taking other people's recommendations on sizes, types, techniques, etc. but rather making those decisions yourself from an informed position. What current will be passing through this wire? What is it's resistance per metre, therefore what will be the voltage drop and power consumption?

In that blog you linked to, Oddcopter says he used 18AWG wire to make his spider because with that size he could fit 4 of them into the back of an EC5 connector! He may be using the right size, but for a really wrong reason! And, as Sleepy points out, bullets are a bad choice: they tend to disconnect themselves under vibration. If you do use them you should heatshrink over them so that they cannot come apart (which makes them a pain anyway).

One problem that is rarely mentioned is the vulnerability of soldered wires in a vibration-rich environment. When you solder a wire to a connector (or to a PDB or ESC) a certain amount of solder will travel up inside the insulation (called "wicking"). The longer you leave the heat applied, the further it will travel. In use, the transition point between solder and the copper conductors is a severe "weak spot" which is highly susceptible to fracturing under vibration. To mitigate this risk, such a joint should always be supported beyond this interface point: as a minimum, one or two layers of heatshrink - much better would be a physical "strap down" point. Commercial aircraft wiring and automotive wiring both follow this principle, yet it is widely ignored in our multirotor world.

Consider, too, the benefit of crimping versus soldering. There are many advantages - look into "Anderson Powerpole" connectors. Connectors with positive locking is another feature to ponder. Positive/negative power wires should always be twisted together to minimise interference.

A final thought: the RC retail business is full of poorly designed products (usually at absurdly inflated prices) that are "designed", often, just to be different from whatever else is being sold. You should disregard widespread availability and popularity - they are not reliable indicators of quality or suitability! Much better to look at other industries and see what components/techniques they use (and why).

thanks for the elaborate response. I've studied physics, so the calculations of power, voltage, amps and resistance are well-known to me, including internal resistance of wires (which is more high school stuff btw). *However* there is a huge difference between theoretical knowledge and practice. Your next point about vibration fracturing illuminates that point quite clearly. To put it simply: it would not have occurred to me until the rig came crashing down and I found out about the fractured solder point....so thank you for that.
What is also funny is the direct opposite of what I read somewhere else: 'don't using crimping as its a pain as you are constantly changing parts'. Nice to see both poles. Overall I prefer a bit more hassle on the ground over a craft that comes crashing down....

Anymore good advice, certainly like this, is most welcome.

 

[Motopreserve]

I think the crimping Jes was talking about was the crimp style connectors (such as the Anderson instead of Deans or XT-60/90). This would not add any more hassle to your startup procedure. It just swaps a crimp for a solder when making the power harness, or modifying battery leads.

Jes, are you using thi style connector elsewhere on the multirotor?

 

[jes1111]

Jes, are you using thi style connector elsewhere on the multirotor?

I use Andersons wherever I can

This is an ESC32 I was playing with the other day - Andersons for power and motors :highly_amused:

The black shape on top of the blue/orange connectors is a locking piece - guarantees the connector can't come apart in flight. The orange Andersons are soldered straight to the PCB (using Anderson's special contacts designed for PCB attachment). The blue/red/black ones are crimped.

(Eagle-eyed viewers will notice the middle FET is blown, and one of the legs on the capacitor. Serves me right for buying a cheap copy of the ESC32 - it was just for an experiment so I thought I'd chance it.)

 

[Carapau]

And I thought I was the only one using APPs - good to know I'm not alone. APPs are the easiest and most resilient connectors in my mind. I've used them on my helis for years and they are just awesome.


Sent from my iPhone using Tapatalk

 

[Motopreserve]

Jes,

do you notice a big difference/improvement with the ESC32 vs the more typical SimonK flashed type? I've recently been reading up on them. I know Witespy sells some - look a lot like the one you posted above.

pretty nifty with those connectors soldered right to the board. I'd be afraid I'd ham-fist it and the AP connector would be fine, but I'd have half the PCB in my hand after trying to switch out one of those

 

[jes1111]

Yes - that's from Witespy. Don't know if the unit was defective or it was my dodgy servo tester - could be the latter. Never mind. However, I only bought the one because I wanted to try out the undocumented "servo mode" (for gimbal control). Since the experiment came to an abrupt halt, I can't comment any further! I want to get a set of the real Autoquad ones to try in the air but they are out of stock everywhere at them moment. And I'm too busy with other stuff, as always

No danger of breaking the PCB with those Andersons - the mounting is solid as a rock. The insertion/disconnection force is surprisingly low - you have to handle these suckers to appreciate how well they're designed.

 

[Motopreserve]

Yes - that's from Witespy. Don't know if the unit was defective or it was my dodgy servo tester - could be the latter. Never mind. However, I only bought the one because I wanted to try out the undocumented "servo mode" (for gimbal control). Since the experiment came to an abrupt halt, I can't comment any further! I want to get a set of the real Autoquad ones to try in the air but they are out of stock everywhere at them moment. And I'm too busy with other stuff, as always

No danger of breaking the PCB with those Andersons - the mounting is solid as a rock. The insertion/disconnection force is surprisingly low - you have to handle these suckers to appreciate how well they're designed.

ive got them on the bench as we speak (actually, I need to order more), awaiting install. I'll get to it eventually At very least I want to swap out my XT-60 batteries to power lead.

i have been been flirting with the idea of the ESC32 - I have one of the Witespy pro ex3 boards. Been very happy with everything I've gotten from him. Seems like this new tech for these ESC could be a game changer. Just not sure if it's all there yet.

More research....

 

[daddywoofdawg]

One problem I saw on the oddcopter build is never put male connectors on the battery end,always female,males will touch and spark/short out.

 

[Motopreserve]

One problem I saw on the oddcopter build is never put male connectors on the battery end,always female,males will touch and spark/short out.

Definitely true. You do NOT want male ends on the batteries. That can lead to very bad (and expensive!) things....