Solar Panel connectors - MC4 and replacements

Sak_newhere · November 2019

Hey everyone,

I am relatively new to this field and was hoping to get some help.

I have a few questions about the MC4s and their ideal replacements. I read the discussions about the MC4s, pros, cons in many forums and I don't want to go for them. I checked about Anderson Power Pole and few others but they don't seem to fit in my scenario. I was wondering if there are any ideal replacements for the MC4 Y connectors? The entire setup would be used on an EV (around 6 - 10 panels) therefore, should be able to withstand extreme conditions, vibrations etc. Any suggestions would be highly appreciated.

Many Thanks!

littleharbor2 · November 2019

Buy or build a combiner box. Here's a basic one.

Image: https://us.v-cdn.net/6024911/uploads/editor/5f/ujepggnm5ugu.jpg

Sak_newhere · November 2019

Hey mate,

Thanks a lot for the reply. It is pretty much interesting and I have a direction now. But I forgot to mention that I have some constraints when it comes to the dimensions. The height of the connector/combiner box should just be 1.5 cm including the casing if needed for the ambient resistance. The length and breadth wouldn't matter that much. I went through Dinkle power boxes and I reckon that the height of any combiner box when placed horizontally or vertically would be more than that. This was the reason to go for MC4 Y in the first place. Are there anything that could fit in this bracket?

Thanks!

littleharbor2 · November 2019

I think you could build one from scratch, although probably not with integrated fusing. There are inline fuses you can use. Using these you can combine with MC-4 branch connectors. Once you combine 3 or more panels they need to be individually fused.

Image: https://us.v-cdn.net/6024911/uploads/editor/1p/d6xqmwhaxe4d.jpg

Sak_newhere · November 2019

Thanks mate! I don't want to use the MC4s, therefore, I will check on how I could build a combiner box. Thanks a lot!

Sak_newhere · November 2019

I was wondering if there are any Anderson Power Pole connectors / other connectors that combines multiple input strings and delivers a single output pair which could be coupled with the solar panels (other than MC4s). I found one website link that gives a similar product (3 in 1 Power Pole) but couldn't find any other similar products that combines multiple input strings and delivers a single output pair.

https://www.grandado.com/products/3-in-1-50a-12v-anderson-connector-harness-stekkerconnector?variant=15896725192798&currency=EUR&gclid=Cj0KCQiA5dPuBRCrARIsAJL7oejGwui9tAE1cghtzIUWqzyOM6vEE1AI0wuKI3i_npdI4J8NzsCfIAAaAgdOEALw_wcB

Image: https://us.v-cdn.net/6024911/uploads/editor/6v/w4eeplt8h3ty.jpg

BB. · November 2019

You can find some various Power Pole assemblies in HAM radio stores:

https://www.mfjenterprises.com/Product.php?productid=MFJ-1106

But I am not sure I would go down that route. Cutting off and wiring up with new weather proof or simply crimp splices with a few wraps of self vulcanizing tape, a few wraps of plastic electrician's tape, and a coating of 3M sealant... That is what we did on shipboard electronics/wiring connections exposed to weather (and even with radio antenna connectors)--Of course, took all the tape off once every year or so, inspected, and re-sealed.

But I doubt anyone would want to do that... Our host has various combiner boxes (just cut wire ends, and MC4)...

https://www.solar-electric.com/search/?q=combiner+boxes

I would not suggest Anderson Power Pole connectors for exterior connections... (the ones I am aware of) Power Pole is not water/weather tight, and you would need to install them in weather tight a J-Box with drip loops, etc. anyway.

Y connectors can work for smaller system (just a few panels)--But more than that, really need a combiner box of some sort (even just a utility AC distribution panel, "wired backwards" (circuit breaker protected branch circuits to panels, main buses to charge controller).

Of course, you have to have the right DC rated breakers for such a panel too...

-Bill

photowhit_crap · November 2019

Sak_newhere said:

I was wondering if there are any Anderson Power Pole connectors / other connectors that combines multiple input strings and delivers a single output pair which could be coupled with the solar panels

Not sure why you want to reinvent the wheel. Anderson connecters are not water tight, I would not use them where they were not intended.

Have you seen massive failures in MC4 connectors? I can't recall a failure in 100 or so panels I've installed. We get plety of vibration with 60+ mph winds and 17 inches of snow last year.

Image: https://us.v-cdn.net/6024911/uploads/editor/mm/99y0d4qhachb.jpg

If you do find a replacement, be sure that the wiring is designed for UV protection.

Sak_newhere · November 2019

BB. said:

You can find some various Power Pole assemblies in HAM radio stores:

https://www.mfjenterprises.com/Product.php?productid=MFJ-1106

But I am not sure I would go down that route. Cutting off and wiring up with new weather proof or simply crimp splices with a few wraps of self vulcanizing tape, a few wraps of plastic electrician's tape, and a coating of 3M sealant... That is what we did on shipboard electronics/wiring connections exposed to weather (and even with radio antenna connectors)--Of course, took all the tape off once every year or so, inspected, and re-sealed.

But I doubt anyone would want to do that... Our host has various combiner boxes (just cut wire ends, and MC4)...

https://www.solar-electric.com/search/?q=combiner+boxes

I would not suggest Anderson Power Pole connectors for exterior connections... (the ones I am aware of) Power Pole is not water/weather tight, and you would need to install them in weather tight a J-Box with drip loops, etc. anyway.

Y connectors can work for smaller system (just a few panels)--But more than that, really need a combiner box of some sort (even just a utility AC distribution panel, "wired backwards" (circuit breaker protected branch circuits to panels, main buses to charge controller).

Of course, you have to have the right DC rated breakers for such a panel too...

-Bill

Hey Bill,

Thanks a lot for the suggestions. I have also read that the APPs are not water resistant but was wondering if I can use some body covers of the company-make (Anderson Power Products) to shield the connector. Just curious!!!

I have already gone through the combiner boxes but I have some tolerance level / constraints when it comes to my design. The combiner box can easily go upto 10 cm of height whereas I have a minimum allowable limit of just 2 cm, hence my interest lies in connectors like APPs etc.., If I don't find any replacements, I will find a way to use a combiner box. Cheers!

When you say 'Y' connectors, do u mean MC4 Y?

Regards,
Sakthi,

Sak_newhere · November 2019

photowhit_crap said:

Sak_newhere said:

I was wondering if there are any Anderson Power Pole connectors / other connectors that combines multiple input strings and delivers a single output pair which could be coupled with the solar panels

Not sure why you want to reinvent the wheel. Anderson connecters are not water tight, I would not use them where they were not intended.

Have you seen massive failures in MC4 connectors? I can't recall a failure in 100 or so panels I've installed. We get plety of vibration with 60+ mph winds and 17 inches of snow last year.

If you do find a replacement, be sure that the wiring is designed for UV protection.

Thanks for the suggestions. There may be advantages of MC4s but I am trying to find a replacement for my design. Having said that, which brand of MC4 do you recommend ?

Thanks mate!

BB. · November 2019

Using Y (including MC4 Y) connectors in power systems are always difficult to do "safely". N+1 power supplies (lots of paralleled power supplies) and distributing power from a central bus to multiple locations almost always require fuses/circuit breakers to reduce the chances of fire from a short circuit/over current event.

About the only way to avoid using a bunch of breakers/fuses is to design "all the wiring" in a branch circuit to carry the maximum amount of current available from the energy source(s). But this is an expensive (lots of $$ copper) and heavy/awkward solution (working with heavy/stiff copper wiring where only a small diameter cable is needed for the actual current flow).

-Bill

BB. · November 2019

Regarding your question of which brand(s) of MC4 connectors... It has been too many years since I have been out of industry using connectors to give you a good answer.

Also, MC4 connectors are (I guess) copyrighted/patented and cannot be made by "anybody"... So you end up with MC4 connectors that are close, "compatible", or look about the same but not compatible. And getting bulk MC4 connectors seems to be less than easy to find too.

Call up your supplier and see what they sell/recommend. Or perhaps some other folks here can give you the current answer.

-Bill

icarus · November 2019

^Actually, Amazon is filled with MC4 connectors and tools:

https://www.amazon.com/PowMr-Pairs-Mc4-Solar-connectors/dp/B07R8BXH6B/ref=sr_1_1_sspa?keywords=Mc4+solar+connectors

Can’t speak to the “authenticity” of any of these, but I have bought many and they all seem to work just fine, if you have the proper crimping tool.

T

Photowhit · November 2019

Thanks for the suggestions. There may be advantages of MC4s but I am trying to find a replacement for my design. Having said that, which brand of MC4 do you recommend ?

I don't know about the connectors, I purchased 50 sets or so many years ago and they have worked fine for me, I have read about people buying ones they were not happy with, I think most often when people have stated that here they were trying to mate MC4 connectors with Tyco(?) connectors another type of waterproof connectors which look similar.

Still haven't heard of any problems you have had with the connectors, or if you have had any problems.

I would suggest a couple think in using MC4 connectors, Do not use a single hinge design crimper, they don't work well. I have one purchased (dearly) many years ago and would replace it if I was doing any large job again. The make an anvil type crimper today that costs less than half of what I paid and replicates the action of the UL crimps very closely.

Anvil type crimper, where the action goes straight up and down;

Picture 5 of 12

I would also be careful about what type of wire you buy to use the connectors on. The selection of UV protected wire is pretty slim, USE2 wire is almost or always 7 strand and difficult to crimp. I did my first array solely with USE 2 wire and basically I just clipped 1 strand and hand fed the 3 strands into each side of the crimp. This made a quick job very tedious and time consuming, but it was the only way I could get a good crimp. PVwire is 19 strands and much easier to get a proper crimp! Back to a quick job!

If you buy premade wire, check it! I bought some because it was cheaper per foot than I could find. I had to cut off the soldered connecters and do my own. The were MC4 connectors, but not designed for crimping and had been soldered only. Not good for a wirethat will hve constant micro vibrations from wind and rain.

Sak_newhere · November 2019

BB. said:

Regarding your question of which brand(s) of MC4 connectors... It has been too many years since I have been out of industry using connectors to give you a good answer.

Also, MC4 connectors are (I guess) copyrighted/patented and cannot be made by "anybody"... So you end up with MC4 connectors that are close, "compatible", or look about the same but not compatible. And getting bulk MC4 connectors seems to be less than easy to find too.

Call up your supplier and see what they sell/recommend. Or perhaps some other folks here can give you the current answer.

-Bill

Hello Bill,

Rightly said! One of the best options as you stated is to have a conversation with the supplier for better understanding of the compatibility with the tail end connection of the solar panel and choice of the MC4. If I am choosing to go with the connectors, I have certain pre-written pointers to carefully select like the choice of company, crimping tool and certain conventions with regards to mounting etc. So, thanks a lot for the messages

Regards,
Sakthi.

Sak_newhere · November 2019

icarus said:

^Actually, Amazon is filled with MC4 connectors and tools:

https://www.amazon.com/PowMr-Pairs-Mc4-Solar-connectors/dp/B07R8BXH6B/ref=sr_1_1_sspa?keywords=Mc4+solar+connectors

Can’t speak to the “authenticity” of any of these, but I have bought many and they all seem to work just fine, if you have the proper crimping tool.

T

Thanks! hahaa.. Yes, I have also checked amazon and could find a lot of MC4s. As stated in the previous message to Bill, I will follow the guidelines that I have, if I am going with MC4s.

Sak_newhere · November 2019

Photowhit said:
Thanks for the suggestions. There may be advantages of MC4s but I am trying to find a replacement for my design. Having said that, which brand of MC4 do you recommend ?

I don't know about the connectors, I purchased 50 sets or so many years ago and they have worked fine for me, I have read about people buying ones they were not happy with, I think most often when people have stated that here they were trying to mate MC4 connectors with Tyco(?) connectors another type of waterproof connectors which look similar.

Still haven't heard of any problems you have had with the connectors, or if you have had any problems.

I would suggest a couple think in using MC4 connectors, Do not use a single hinge design crimper, they don't work well. I have one purchased (dearly) many years ago and would replace it if I was doing any large job again. The make an anvil type crimper today that costs less than half of what I paid and replicates the action of the UL crimps very closely.

Anvil type crimper, where the action goes straight up and down;

I would also be careful about what type of wire you buy to use the connectors on. The selection of UV protected wire is pretty slim, USE2 wire is almost or always 7 strand and difficult to crimp. I did my first array solely with USE 2 wire and basically I just clipped 1 strand and hand fed the 3 strands into each side of the crimp. This made a quick job very tedious and time consuming, but it was the only way I could get a good crimp. PVwire is 19 strands and much easier to get a proper crimp! Back to a quick job!

If you buy premade wire, check it! I bought some because it was cheaper per foot than I could find. I had to cut off the soldered connecters and do my own. The were MC4 connectors, but not designed for crimping and had been soldered only. Not good for a wirethat will hve constant micro vibrations from wind and rain.

Hello,

Seems like I have to learn a lot about crimping. Thanks for the detailed do's and dont's. From the different conversations I have had so far, I understand that the crimping method and the selection of crimping tool plays an integral part in the mating of the connectors.

Personally, it is just been few days since I took up the project. My colleagues have been working with MC4s for a very long time and they have had a lot of issues and thus, I am trying to find alternative solutions for the design we have in place. I will explore more on this and get back to you if I have some doubts.

Thanks,
Sakthi.

garynappi · December 2019

I have what you can call a minimal system and found that having an MC4 crimping tool invaluable. Also as mentioned above a solar combiner is a good way to start. I got the pre-wired model below for ~$50 and there was enough room inside to mount two circuit breakers. Also with the MC4's below the box they are shielded from rain.

Image: https://us.v-cdn.net/6024911/uploads/editor/78/jw6mitdqgwmt.jpg

softdown · December 2019

There are a lot of ways to do connections. All with fans and detractors - pros and cons. There are a lot of ways for a solar installation to fail. I think it is about paramount to have a system voltage readout that you can very easily keep an eye on. Mine involves twisting my head 45 degrees - I'll likely catch a problem on the quicker side.

Sak_newhere · December 2019

garynappi said:

I have what you can call a minimal system and found that having an MC4 crimping tool invaluable. Also as mentioned above a solar combiner is a good way to start. I got the pre-wired model below for ~$50 and there was enough room inside to mount two circuit breakers. Also with the MC4's below the box they are shielded from rain.

Hey, Thanks for sharing your experience and for the suggestion pal. I have kinda decided to go with designing DIY combiner box. Hopefully, it should come out well.

- Sakthi

Sak_newhere · December 2019

softdown said:

There are a lot of ways to do connections. All with fans and detractors - pros and cons. There are a lot of ways for a solar installation to fail. I think it is about paramount to have a system voltage readout that you can very easily keep an eye on. Mine involves twisting my head 45 degrees - I'll likely catch a problem on the quicker side.

Hey man,

Honestly, its been just a month and I have personally learnt a lot from all the different experiences of so many experts here. Irrespective of the pros and cons where it helps in most of the cases, sometimes a design/product that works well for one would not be a right choice for another. 45 !!! I agree on that! hahaaaa,

- Sakthi

littleharbor2 · December 2019

Sak_newhere said:

Hey, Thanks for sharing your experience and for the suggestion pal. I have kinda decided to go with designing DIY combiner box. Hopefully, it should come out well.

- Sakthi

I have built lots of combiner boxes from scratch. All parts are easy to find on eBay starting with din rail stock and all circuit breakers, fuse holders etc. that work on din rail. There's a a certain satisfaction in building your own combiner. Whether your time is more valuable than the cost of a pre-made one is up to you.

softdown · December 2019

littleharbor2 said:

Sak_newhere said:

Hey, Thanks for sharing your experience and for the suggestion pal. I have kinda decided to go with designing DIY combiner box. Hopefully, it should come out well.

- Sakthi

I have built lots of combiner boxes from scratch. All parts are easy to find on eBay starting with din rail stock and all circuit breakers, fuse holders etc. that work on din rail. There's a a certain satisfaction in building your own combiner. Whether your time is more valuable than the cost of a pre-made one is up to you.

Seems like everyone here is a mcgivor.

Solar Panel connectors - MC4 and replacements

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