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Dear Homebuilt Electronics Manufacturers...

I'm surprised to see the hate on apparently all Molex connectors here.

We've been using them in various forms on all our EFI and EI products for 27 years and closing in on 11,000 controllers now. Collectively something over 15 million hours and some of those used in multiple Baja 500/1000 wins where the pounding and vibration far exceeds anything seen in aviation.

Crimp the pins right and support the wiring properly and they are very reliable.

Never had a Mate-n-lock unlock by itself. It takes a really good pull to do this.
 
And with perfect timing Kitplanes publishes an article extolling the virtues of Molex connectors! https://www.kitplanes.com/aero-lect...ANES+Weekly&utm_campaign=KP+Weekly+2021/03/23

In my opinion these lower cost connectors have their place, but that place is not on ignition systems or IFR critical avionics!

With respect to the FlyLeds product, when I first began researching my build 8 or so years ago I was intrigued by the possibility of LED lighting but dismayed by the cost of the products available then. When I first saw FlyLeds I knew what I was going to install on my plane. I for one really appreciate the fact that Paul has brought to market an innovative and low cost product that is truly in the spirit of home building.

I fear that the quest for " Aviation quality" throughout will eventually price a lot of people out of our hobby.
 
I'm surprised to see the hate on apparently all Molex connectors here.

We've been using them in various forms on all our EFI and EI products for 27 years and closing in on 11,000 controllers now. Collectively something over 15 million hours and some of those used in multiple Baja 500/1000 wins where the pounding and vibration far exceeds anything seen in aviation.

Crimp the pins right and support the wiring properly and they are very reliable.

Never had a Mate-n-lock unlock by itself. It takes a really good pull to do this.

I don't "hate" the (thousands of sizes) molex connectors. They do stay together and crimp well, but the open to the air, corrosion is my concern. I say concern, because I used them where manufacturers specified as reinvention can be a rocky road. Corrosion might be ok for a high power strobe connector but terrible for a low voltage/amperage/PWM signal from sensors and other electronic devices.

The reservation comes from years (decades) of seeing connection failures and subsequent vendor changes for on-highway truck engines and off highway heavy equipment in my professional life. That is a tough dirty environment. Using Deutsch DT connectors on a whole airplane is heavy and expensive - - - although they are very reliable. DT is the only one I know has passed severe vibration, sealing and abuse testing. ECM connectors are another matter.

The concern about non-sealed connectors does not go away, though. Our planes should have a long service life.
 
I don't "hate" the (thousands of sizes) molex connectors. They do stay together and crimp well, but the open to the air, corrosion is my concern. I say concern, because I used them where manufacturers specified as reinvention can be a rocky road. Corrosion might be ok for a high power strobe connector but terrible for a low voltage/amperage/PWM signal from sensors and other electronic devices.

The reservation comes from years (decades) of seeing connection failures and subsequent vendor changes for on-highway truck engines and off highway heavy equipment in my professional life. That is a tough dirty environment. Using Deutsch DT connectors on a whole airplane is heavy and expensive - - - although they are very reliable. DT is the only one I know has passed severe vibration, sealing and abuse testing. ECM connectors are another matter.

The concern about non-sealed connectors does not go away, though. Our planes should have a long service life.

Many Molex connectors commonly used are not weatherproof and are not designed for FWF in our application. If that's where you're making connections, I agree, they should be Deutsch or Weatherpack types designed for that environment. I wouldn't think of using any open ended connector FWF in an automotive application with the wet and possibly salty conditions present. That would be asking for trouble down the road.

In the confines of the cabin, non sealed Molex connectors work reliably. We have something over 15 million hours collectively on our systems using these with some of those up to 27 years old now. We haven't seen connector issues or pin corrosion issues even in humid climates on these. The pins are typically tin plated.
 
Many Molex connectors commonly used are not weatherproof and are not designed for FWF in our application. If that's where you're making connections, I agree, they should be Deutsch or Weatherpack types designed for that environment.

Keep in mind that weather-sealed connectors like Deutsch are also good at keeping moisture *in*. In an engine compartment that heats up and cools down, condensation is a thing.
 
Keep in mind that weather-sealed connectors like Deutsch are also good at keeping moisture *in*. In an engine compartment that heats up and cools down, condensation is a thing.

The sealed connectors tend to minimize the captured air and with gold plated machined pins the little moisture that might be present is not an issue.
 
Keep in mind that weather-sealed connectors like Deutsch are also good at keeping moisture *in*. In an engine compartment that heats up and cools down, condensation is a thing.

The OE auto sealed connectors work well. They were designed for high salt/water environments- FAR worse than anything RVs will ever see. We've used them in marine applications. Never see corrosion inside them. The air volume inside is tiny when they're connected.

People can theorize all they want but with 27 years in this business and many thousands of systems in service with tens of thousands of connectors in service, I don't see these issues with the sealed automotive connectors we use.
 
The sealed connectors tend to minimize the captured air and with gold plated machined pins the little moisture that might be present is not an issue.

Gold plating is not a panacea. Gold is used for 'dry' connections (i.e. low current) such as low voltage signals. Put any appreciable load current through a gold plated connector and the gold will migrate and eventually expose the underlying connector material to corrosion.

For 'wet' connections (power connections etc.) The connections should be tin or silver based. Using tin or silver connectors for low level signals may introduce problems as an oxide film will build up and may cause intermittent operation or voltage offsets (such as EGT and CHT probe connections).

The idea idea of 'wetting current' is to provide enough current so that a connection is self cleaning due to the current flow. If you want to use a tin based connector to handle a low level signal (such as a switch input), you need to provide this wetting current for reliability. That means several 10's of milliamps.

Of course, there are gold over tin or silver connections that can handle both. If it's used for large currents, the gold migrates and exposes the underlying tin/silver connection which is fine. The only problem is that you can't use those pins for low current applications afterwards.

These arguments also apply to switches and relays. The contact design is important for the application.
v
 
Deutsch has nickel plated machined pins for power applications.

Nickel is good except in high humidity environments. Tin is resistant to water. So Deutsch connectors need to be sealed, while it is not a requirement for tin. So it’s a never-ending debate.
 
Wow

It is amazing, that with all of the issues being discussed, that our aircraft aren’t falling from the skies, tractors and machinery failing mid harvest, and cars stranded on the side of the road...all due to connector failures...

There are NO perfect systems...
 
Cannon Plugs?

Should we be using old/timey Amphenol/Cannon plugs? They’re just a bit pricey but they’re available in thousands of configurations and sizes.
 
I think the thing with Molex is to first crimp the wire and then the insulation to the pin, and then solder the wire to the pin. I've never had any trouble after doing this.

for 20ga and smaller, I think d-sub is best.

I had many failed pull tests on crimped terminals until I figured out that the AMP brand with the right crimper was the only one which never failed
 
Walt, I've used a lot of D-subs, but I know nothing about CPCs. What type of pin do they use (Same as D-sub I hope!)? Are there particular CPCs that you like for particular applications? Size/No. of pins/amp limitations/free-hang or mount?

-Dave
 
CPC Series II and Mate-N-Lok

Vern,

This is helpful. Can you point me to part numbers for the CPC and the Mate-N-Lok?

Thanks,
Dave
 
There was a lot of comment regarding the Molex in VAF or, more specifically, why Molex should not be used. Below is the screen grab from steveo1kinevo
youtube video when he was discussing the repair on the multi-million dollars TBM turbo prop. You can see that the Molex connectors are used everywhere in this airplane. The electrical cables are zip-tied instead of lacing. I feel a lot better having Molex and zipties in my RV8 now. In addition to using ProSeal, this stuff is used on the big turboprop to seal up the pressurized cabin. OT: Just in case you think your ProSeal job is messy, the pro work isn't as cleaned either.

Link to the vid. https://www.youtube.com/watch?v=LLWsuqdfVQo
I found some of the information very useful since it's not about flying but repairing aluminum airplane.
 

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