MC4 scam buster - what you have all been waiting for

[Boron]

Hi Guys - this is not a clickbait rubbish. Its my genuine attempt to overcome the serious MC4 problem - a demountable connection system that doesnt burn out on you.

So here is my Mk1 version
Solid brass mechanical straight coupling using 2 pairs of hex grub screws. The cable is standard 6mm2 solar TUV (10AWG). I hope the poor quality pix are self explanatory.
You could use a rubber tube (UV res) as a simple cover and squirt some Si grease in to keep water out. Or you can use a heatshrink sleeve if you dont expect to have to demount it (by stripping the sleeve - less convenient maybe.
Rated for 50A as per cable. Cost <$1. No crimping tool needed as the grub screw points and copper sleeve grip the strands tightly.

What do you think? Armchairs - do your worst

BTW I have no commercial interest - the design is offered as GNU for the benefit of Solar Members and saving on roof fires.

 

[Mattb4]

Do you have a name and possible link for the inline coupler? The idea could be refined by having it handle different wires sizes at junction by reducing one end. That way if you had 8awg feeder wire and the panels wires were 12awg it would match properly.

 

[Boron]

This is evaluation and development in progress. Different size wire couplings are certainly available. I want others to try this solution out. This takes time. I am building a 500A test bench to check out all these basic components. IMHO this area has all been trivialised and glossed over by Cheap Charlie

 

[robbob2112]

One thing - quality of brass has a huge impact in ampacity per mm^2 ... from 1.2 to 3.96.... and we know how mfg like to save a buck... Too little copper and you have a bad connection.

I would like to see these after running say 30 amps through them for a while with a thermal camera - with and without heat shrink - in and out of the sun - and most important in the sun on a roof.

Also, what prevents the set screw from backing out of them from the expansion/contraction - having to send the average user up on the roof multiple times a year to check torque on a screw without stripping the head seems dubious at best.

 

[Boron]

One thing - quality of brass has a huge impact in ampacity per mm^2 ... from 1.2 to 3.96.... and we know how mfg like to save a buck... Too little copper and you have a bad connection.

I would like to see these after running say 30 amps through them for a while with a thermal camera - with and without heat shrink - in and out of the sun - and most important in the sun on a roof.

Also, what prevents the set screw from backing out of them from the expansion/contraction - having to send the average user up on the roof multiple times a year to check torque on a screw without stripping the head seems dubious at best.

Well here we have a crock of armchair speculation - that doesnt stack up
I will publish some figures for 50A when I get set up. The yellow brass is likely free machining (1%PB). This type of screw clamping is commonplace as per choclate blocks and consumer units not known for unscrewing (are you confusing the Aluminium wiring once common across the pond)

Also, what prevents the set screw from backing out of them from the expansion/contraction - having to send the average user up on the roof multiple times a year to check torque on a screw without stripping the head seems dubious at best. YMMV

If you want to have some skin in the game you need to do some testing yourself. I think these are fine for 50A till I prove myself wrong (and IMHO a lot more credible than the mickey mouse alternative that is a known problem area.)

 

[robbob2112]

Ask for opinions and spit in my face when I respond

 

[seneysolar]

Why brass?

Brass is not a good conductor

 

[LydMekk]

Brass should never be used in solar. IMO.
Copper-Yes, Brass-No.
For outdoor use copper should also have a layer of f.ex. nickel or other materials to stop the "green process" (sry, didnt remember what it is called).

Btw. for good quality MC4 buy Staubli.
Never had issues with mine.

 

[robbob2112]

I guess he got deleted or booted or something

 

[seneysolar]

I guess he got deleted or booted or something

Well he said-
"What do you think? Armchairs - do your worst" but sure didn't like what you had to say