Which connector - Molex or CPC?

[231MJ]

I'm gathering the parts to install the Dynon AP - each servo needs a connector for power and ground separate from the control wires. I'm trying to decide on a connector.  Which is preferred, Molex or CPC?  Molex is a fraction of the cost of a CPC connector, and it looks easier to deal with. Any recommendations?

[KSMooniac]

Does Dynon specify something in particular?  

I've become a fan of the Deutsch connectors and have been using them as I upgrade things on my plane.  They're at my wingtips and tail for the strobes and nav lights, landing light connection under the cowl, glareshield lights, etc.  You need a proper crimp tool for them.  I like them much better than the knife connectors + heat shrink + zip ties that were standard in 1977 (in my case).

[MikeOH]

As a retired EE, I HATED Molex connectors; cheap, crap product. Consequently, used EVERYWHERE.  Good for about two plug/unplug cycles.

I'd follow the 'get what you pay for' and buy the better connectors.

[Aerodon]

Molex (Mate 'n Lock) are not bad, especially if you find gold plated pins, have the correct crimper and make sure you get the 'locking' shells.  

Mooney 'overused' CPC connectors, but they are nice too, with high quality pins and sockets.

Trick is whatever you use, get the proper crimpers and pins.

 

Aerodon

 

 

 

 

 

 

[larryb]

Another retired EE here, and I do like the Molex connectors. I use them extensively for personal projects. The few issues I have had are in the initial crimping and assembly. I've never had one fail in service. Having the proper crimper makes using them (or any connector really) much faster and easier. Crimping with needle nose pliers and then soldering is tedious. I would use them in a plane in non-critical areas. 

 

That said, I probably would not use one for autopilot wiring. I would want the best and most reliable connector. I consider the Molex to be adequate, certainly not the best.  I have no experience with the Deutsch connectors but I would look into them. I like that they are environmentally sealed. CPC connectors are not environmentally sealed. 

 

Finally, Molex connectors are not the same as Mate-N-Lok. The are similar but not compatible with each other. My Mooney has a number of Mate-N-Lok connectors from the factory. 

 

Larry

[231MJ]

Thanks, guys!  I like the CPC connectors because they have strain relief, but they are expensive and very bulky.  I was not familiar with the Deutsch connectors, but they seem perfect for my application and copilot (AI) says they can be used in aviation applications.  I'm going to try them for the servo power connectors and also to get rid of the knife connector for the landing lights. Cost wise (I am a Mooney owner, after all) a Deutsch kit (including the crimping tool) is about the same as 4 CPC connectors but you get a lot more connectors in the kit (Amazon aviation supply house).

[Fly Boomer]

1 minute ago, 231MJ said:

copilot (AI) says they can be used in aviation applications

I think I read somewhere that AI supersedes FAA.

[231MJ]

larryb,

Would you use Mate N Lok for the AP power connectors? It looks like they are sealed.  I know I'm over-thinking this...

[EricJ]

Some people won't like the idea, but the Delphi Weather Pack connectors are very good and designed for wide temperature ranges, vibration, and keeping weather/water out.  

If you just need one or two you can sometimes get them off the connector rotary rack at an automotive store, or Mouser, or Amazon or a bunch of places.   They're pretty popular.   They're pretty much my go-to when I need a reliable connector with good environmental qualities.

 

[MikeOH]

3 minutes ago, EricJ said:

Some people won't like the idea, but the Delphi Weather Pack connectors are very good and designed for wide temperature ranges, vibration, and keeping weather/water out.  

If you just need one or two you can sometimes get them off the connector rotary rack at an automotive store, or Mouser, or Amazon or a bunch of places.   They're pretty popular.   They're pretty much my go-to when I need a reliable connector with good environmental qualities.

 

I'll second the Weather Pack recommendation. Frankly, I think they are better than some high-priced MIL-spec connectors both in terms of reliability and environmental resistance...and at MUCH lower cost! 

[larryb]

larryb,
Would you use Mate N Lok for the AP power connectors? It looks like they are sealed.  I know I'm over-thinking this...

No I wouldn’t. Mate N Lok are not sealed and are not positive locking. They are kind of friction locked. I’d use them for non critical things such as USB power ports, music, less important lighting, etc. And only in dry low vibration areas.

I think of the auto pilot as a safety critical item. Of course we all know how to fly the plane without the AP but I would want my AP install to be as robust as possible. After paying thousands for the AP it doesn’t make sense to be cheap on the servo power wiring.

Also, I am an EE but not an A&P nor an avionics tech. These are just opinions.

[kortopates]

Technically the only approved connectors are MS and MIL-STD connectors per our AC43.13 although there are other industry standards the FAA cites in AC's on the topic. My Mooney has a ton of CPC connectors along with a great many unapproved connectors too like the knife connectors and molex - but I think mostly Molex connectors are a Whelen thing. I am trying to think where else Molex connectors are used in the Mooney. But I also would shy away from Molex for all the reasons stated above.

I personally like the Deutsch connectors as well that Scott recommends above and these are becoming popular with avionics installers. No experience with the Delphi Weather Pack but my minimum requirements would be a weather sealed/water sealed to protect it from corrosion and use of a certified crimper to ensure the crimp was at least as strong as the wire for a reliable connection and longevity. Deutsch even makes MIL connector but I just use the standard ones.

Personally i think the most important opinion is your install manual (there should be guidance therein) followed by the IA that is going to sign off on your install.

 

[Aerodon]

On 5/22/2025 at 5:46 PM, larryb said:

Mate N Lok are not sealed and are not positive locking. They are kind of friction locked. I’d use them for non critical things such as USB power ports, music, less important lighting, etc. And only in dry low vibration areas.
 

Mate n Lok come in all sorts of variations.  Yes, some are friction lock, but some have detent that lock quite firmly.  I think the pins are rated for about 13A, and they get used all the time in airplanes for landing lights, strobes, FF transducers etc. They are lightweight and easier to secure to a wiring harness than CPC.  I have gold plated pins and would use these for servos.  

I have the luxury of all sorts of crimpers, so can do Mate n Lok, CPC, AMP, Microfit etc. An all sizes of high quality shrink tubing, 

 

Aerodon