MC4 alternatives

[littleharbor2]

All the extra parts and tools including MC-3 dies are a waste of your money. I can pretty much guarantee you will never use the MC-3 dies. Even if you did you would need a special tool $$ to insert the contacts into the rubber housing.
A personal preference of mine is the blue MC-4 crimper style as opposed to the straight line style. I have both and find the blue one much easier to use.

 

[NMNeil]

I'm using Santan Solar second use 250w panels, once all 12 panels were installed I had no intention of removing them until they failed, so all are joined by 10awg marine butt splices, very cheap, waterproof and secure. If you're installing hundreds of new panels I can understand the speed and convenience of MC4.

One of my banks of panels quit on me today.
Of course 104F, too hot to get on the roof, batteries slowly depleting running 2 mini splits, you know how it goes with Murphy's law.
But I had to see what was wrong in case I needed to order anything.
Anyway I found this.

And before you ask, these were supposedly top quality connectors and I used the correct crimping tool.
Marine butt splice connectors on order, and I intend to replace all the MC4 connectors with them as you suggested and possibly add some shrink wrap with the glue inside over the top so it never happens again.
Sweating so much I'm having to go to the supermarket for more beer

 

[Mattb4]

Yeah you will want to fix that. For a temporary fix just cut and strip wires. Twist together and tape. Oh for electrical protection cover your panel with a blanket.

 

[Mike 134]

Yeah you will want to fix that. For a temporary fix just cut and strip wires. Twist together and tape. Oh for electrical protection cover your panel with a blanket.

or work at sundown you'll have over an hour of light with no output

 

[schmism]

One of my banks of panels quit on me today.
Of course 104F, too hot to get on the roof, batteries slowly depleting running 2 mini splits, you know how it goes with Murphy's law.
But I had to see what was wrong in case I needed to order anything.
Anyway I found this.
View attachment 104507
And before you ask, these were supposedly top quality connectors and I used the correct crimping tool.
Marine butt splice connectors on order, and I intend to replace all the MC4 connectors with them as you suggested and possibly add some shrink wrap with the glue inside over the top so it never happens again.
Sweating so much I'm having to go to the supermarket for more beer

That wasnt a connection issue but a, that fitting sat and rubbed through on the panel and shorted issue.

 

[chrisski]

One of my banks of panels quit on me today.
Of course 104F, too hot to get on the roof, batteries slowly depleting running 2 mini splits, you know how it goes with Murphy's law.
But I had to see what was wrong in case I needed to order anything.
Anyway I found this.
View attachment 104507
Sweating so much I'm having to go to the supermarket for more beer

Would you mind sharing the peak amperage and voltage through the cable?

I’m not out to critique. Just curious. What do you think went wrong?

I’m wondering if any of the other connectors show any sign of corrosion.

 

[NMNeil]

Would you mind sharing the peak amperage and voltage through the cable?

I’m not out to critique. Just curious. What do you think went wrong?

I’m wondering if any of the other connectors show any sign of corrosion.

Three SanTan 250 watt panels in series, so around 100V and 6 to 8 amps.
As for what went wrong.
It wasn't abrasion, as the connector was cable tied under the panels to keep the sun off as our climate eats plastic.
Looking at the actual MC4 connector you go from 10AWG copper wire to a very thin steel, possibly tin plated, crimp connector inside the MC4.
Low resistance (copper) to a not so low resistance, friction fit of 2 circular steel parts, which may not be concentric leading to contact in only a few areas, then back to copper.
Lots of possible areas of high resistance, hence heating.
I've ordered these.

200PCS Solder Seal Sleeve Heat Shrink Butt Wire Connectors Terminals Waterproof | eBay

Polyolefin heat shrink butt connectors improved pullout strength, provides seal, strain relief, cable check, and insulation. Solder and seal and with advanced waterproof function. White Heat Shrink Connectors: Suits cable/ wire sizes AWG 26-24 / 0.25-0.34mm2.

www.ebay.com

And these.

Heat Shrink Tubing 3:1 Marine Grade Wire Wrap Adhesive Glue Lined Waterproof | eBay

Dielectric strength: >15kV/mm. This is a waterproof shrink tubing with the internal adhesive layer. When cooled down, it forms a rigid seal. Therefore, 3:1 shrink ratio tubing can be used in significantly more applications compared to 2:1 shrink ratio tubing.

www.ebay.com

Just waiting for them to arrive and the battery bank to recharge.

 

[Supervstech]

Three SanTan 250 watt panels in series, so around 100V and 6 to 8 amps.
As for what went wrong.
It wasn't abrasion, as the connector was cable tied under the panels to keep the sun off as our climate eats plastic.
Looking at the actual MC4 connector you go from 10AWG copper wire to a very thin steel, possibly tin plated, crimp connector inside the MC4.
Low resistance (copper) to a not so low resistance, friction fit of 2 circular steel parts, which may not be concentric leading to contact in only a few areas, then back to copper.
Lots of possible areas of high resistance, hence heating.
I've ordered these.

200PCS Solder Seal Sleeve Heat Shrink Butt Wire Connectors Terminals Waterproof | eBay

Polyolefin heat shrink butt connectors improved pullout strength, provides seal, strain relief, cable check, and insulation. Solder and seal and with advanced waterproof function. White Heat Shrink Connectors: Suits cable/ wire sizes AWG 26-24 / 0.25-0.34mm2.

www.ebay.com

And these.

Heat Shrink Tubing 3:1 Marine Grade Wire Wrap Adhesive Glue Lined Waterproof | eBay

Dielectric strength: >15kV/mm. This is a waterproof shrink tubing with the internal adhesive layer. When cooled down, it forms a rigid seal. Therefore, 3:1 shrink ratio tubing can be used in significantly more applications compared to 2:1 shrink ratio tubing.

www.ebay.com

Just waiting for them to arrive and the battery bank to recharge.

That construction would be VERY unusual… it should be tinned copper, with tinned copper wire.
There should be zero steel in an mc4 connector! Have you confirmed with a magnet?

 

[NMNeil]

That construction would be VERY unusual… it should be tinned copper, with tinned copper wire.
There should be zero steel in an mc4 connector! Have you confirmed with a magnet?

Just tried, and yes, a magnet sticks very firmly to the connector, even through the burned plastic.
So the connectors on my Santan panels are garbage and replacing them all is top of my to do list.

 

[Supervstech]

I would try an acid test, as nickle would still be magnetic... but yeah, copper is ideal.

 

[Supervstech]

Apparently there is only one brand of actual MC4 connector...
All others are supposedly "MC4 compatible"

 

[NMNeil]

Apparently there is only one brand of actual MC4 connector...
All others are supposedly "MC4 compatible"

Or in my case, flammable.

 

[Supervstech]

Or in my case, flammable.

Any time a MC4 connector is introduced, they must be from the same manufacturer... preferably UL listed...

 

[littleharbor2]

Different knock off MC-4 connectors from different makers don't always fit together properly. Some of the contacts fit loosely and can get hot trying to pass current. Question; Were the two fittings from identical panels, mismatched panels or a home run cable?

 

[bones1]

Three SanTan 250 watt panels in series, so around 100V and 6 to 8 amps.
As for what went wrong.
It wasn't abrasion, as the connector was cable tied under the panels to keep the sun off as our climate eats plastic.
Looking at the actual MC4 connector you go from 10AWG copper wire to a very thin steel, possibly tin plated, crimp connector inside the MC4.
Low resistance (copper) to a not so low resistance, friction fit of 2 circular steel parts, which may not be concentric leading to contact in only a few areas, then back to copper.
Lots of possible areas of high resistance, hence heating.
I've ordered these.

200PCS Solder Seal Sleeve Heat Shrink Butt Wire Connectors Terminals Waterproof | eBay

Polyolefin heat shrink butt connectors improved pullout strength, provides seal, strain relief, cable check, and insulation. Solder and seal and with advanced waterproof function. White Heat Shrink Connectors: Suits cable/ wire sizes AWG 26-24 / 0.25-0.34mm2.

www.ebay.com

And these.

Heat Shrink Tubing 3:1 Marine Grade Wire Wrap Adhesive Glue Lined Waterproof | eBay

Dielectric strength: >15kV/mm. This is a waterproof shrink tubing with the internal adhesive layer. When cooled down, it forms a rigid seal. Therefore, 3:1 shrink ratio tubing can be used in significantly more applications compared to 2:1 shrink ratio tubing.

www.ebay.com

Just waiting for them to arrive and the battery bank to recharge.

What crimping tool is good for these?.

 

[MaximusAnonus]

Any time a MC4 connector is introduced, they must be from the same manufacturer... preferably UL listed...

Is there a way to find out who made the connector and what other connectors are compatible? On my DAH panels there is "Jinko" written on the connectors which is supposedly the manufacturer? I can't find these for sale anywhere locally. As these panels are brand new and untested I would like to keep the warranty. Otherwise I would probably just cut/crimp/heatshrink them together.

 

[Charleswgibbs]

What is the point of having a universal connector if they aren't actually universal?

If you need to match brands then basically all solar panel connectors are proprietary. And as the other poster mentioned, how do you even know what brand the panel uses and what if you can't find that same brand?

Does anyone have a suggestion of high quality tinned copper mc4s? I guess it would be smart to replace the panel connector to ensure they match.

 

[MaximusAnonus]

Does anyone have a suggestion of high quality tinned copper mc4s? I guess it would be smart to replace the panel connector to ensure they match.

There is a lot of "made in Germany" connectors available in Europe thought the big wholesale electrical outlets. The problem is if cutting the connectors off truly voids the warranty then it's a catch 22.

 

[chrisski]

I think matching solar connectors is like buying an electric car to save the environment. Everyone has an opinion from zero emissions to back to the old railroad days, powered by coal.

If someone is losing sleep over this, and I do lose sleep over many trivial things, but not MC4s, then cut and replace with Amphenol H4 connectors. Otherwise, buy an MC4 offAmazon after reading reviews and hope for the best.

IMO, most errors are caused by poor installation like bad crimping or poor tightening of the waterproof seals more than manufacturer defects.

 

[Hedges]

or work at sundown you'll have over an hour of light with no output

No current but near full voltage. Check with a DMM before you grab bare wire!

What is the point of having a universal connector if they aren't actually universal?

If you need to match brands then basically all solar panel connectors are proprietary. And as the other poster mentioned, how do you even know what brand the panel uses and what if you can't find that same brand?

That's the present state of the art. Only pairs that were tested and UL listed together are allowed. It isn't a standard anymore.

Does anyone have a suggestion of high quality tinned copper mc4s? I guess it would be smart to replace the panel connector to ensure they match.

I think Amphenol H4 (not exactly MC4) may be good.

H4 PV Connector

The H4 PV Connector is the premiere solar connector in the market today. Carries more amps than the industry standard connector. Meets the NEC 2008/2011 standard “as is” no additional locking-clip required.

www.amphenol-industrial.com

Amphenol Female H4 Connector Contact With Housing

Amphenol Female H4 Connector Housing and Contact

www.solar-electric.com