Mixing MC4 Connectors

[RV Steve]

I know this subject has been discussed in the past and I've read several threads on the topic. I purchased 12 x 100 watt monocrystalline compact Renogy panels on sale ($130 a pair) last year and I plan on installing them on the roof of my travel trailer. I would like to use 8 AWG wire for the longer runs on the roof. My trailer is prewired and has a Zamp 3 SAE port roof cap. I'm planning on running two arrays of 2S3P through two Victron Smart Solar 150/60 TR charge controllers. One array will employ the existing roof port and the other will use a new 2 cable roof port. Unless I use all Renogy cables and connectors I'm faced with mixing "MC4" connectors. I'm planning on running 2S x3 to each of the 3 Zamp SAE ports which combine in parallel and feed to the charge controller via 8 AWG wire. Renogy MC4 to SAE cables are sold out so I'm faced with using what I can find on Amazon which will be 10 AWG with unknown brand Chinese MC4 connectors. I would like to wire the other array using Windy Nation 8 AWG cables and Y branch connectors. Each string will have a 10 amp inline MC4 fuse either Renogy or Windy Nation; I'm leaning towards the latter. Wired in this fashion each array of 2S3P will produce 48.6 Volts and 15.63 Amps open circuit; a little more on sunny cold days.

I'm looking for others practical experiences wiring their panels with other brand "MC4" connectors and whether any issues came up. I would especially like to hear from Renogy panel owners. I know if I made solar cables myself and cut the connectors off of my panels and replaced them with like kind connectors I could solve this issue but most likely would void the warranty on my panels in the process. I also like the idea of using 8 AWG solar cables but setting myself up with a Staubli crimper isn't cost effective for a one time project. I have not been able to find any non Staubli crimper advertised as capable of crimping 8 AWG Staubli MC4 connectors. Staubli also seems to be the only brand of 8 AWG MC4 connectors available.

 

[Mattb4]

You could use 12 AWG (20-25a rated) but 10awg would certainly cover it. There really is no reason to go 8awg.

 

[zanydroid]

You don't need to buy the $$$ Staubli crimper for #10, a lot of licensed installers don't bother with that. $30 kit on Amazon and practice with the junk no-name ones it comes with. For #8, have you tried looking for dies as well as crimpers?

Does Renogy not use MC4? I believe the real MC4 will have markings that the clones tend to not copy.

I'm not seeing where the 3P adds up to needing #8. What is the current calculation? (I don't do RV stuff). There are some ways to attach a junction box to a solar panel frame, you could consider using one to hold splices/fuses/combiner instead of doing it all with cables and Y-connectors.

Did you look To TitanMonroe to see if they have what you want? https://titanwnc.com/

 

[RV Steve]

Mattb4 and zanydroid thanks for the replies. I realize 10, 12, and 14 AWG are rated high enough for my system. I would like to use 8 AWG where ever possible pre charge controller to keep voltage drop to a minimum. Crimping dies for 8 AWG MC4 connectors are available for the Staubli crimper only. I have looked. Correct me if I'm wrong.

I am looking for forum members feedback regarding experiences (good and bad) mixing brands of "MC4" connectors. Staubli is the only brand that owns the MC4 trademark. All others are copies.

Does anyone out there have experience to share?

 

[zanydroid]

There are some non-MC4 that are cross listed for themselves and for MC4, but based on your description of your research you have probably found those and not been able to find #8. By comparison 10 and 12 are needed by a ton of panels and strings. Possibly most users of #8 are using it downstream of combiner boxes rather that directly with MC4 Y connectors.

Have you considered asking a workshop to crimp for you? This is a service that some places offer with an appropriate lead time. My solar distributor offered to arrange that for me (since I needed a bunch of MC4 to Jinko adapters). Titan Monroe might do it. Maybe some of the higher quality distributors of kits

Note that some panel manufacturers will grant warranty clearance letters for customers to remove and recrimp without losing the warranty.

I don’t have experience beyond just parroting the NEC and product listing rule book, and I actually would only trust a forum to be able to speak to what was found after a few year inspection. Because I don’t know what evidence I would be happy with that it is OK, based on random dog on the internet. And there have been forum members that found melted connectors from mixed installs, completed before the listing requirement came in.

 

[zanydroid]

Putting on useless rules lawyering hat: For voltage drop mitigation it is probably legal to parallel two, or as many as you want, #10 even under NEC rules. As long as a single can carry the full current

 

[kendive]

You could use 12 AWG (20-25a rated) but 10awg would certainly cover it. There really is no reason to go 8awg.

I use BougeRV from amazon and used them with large residential to the 100watt Renogy panels for our off grid cabin and no issues at all. I find the BougeRV to be pretty good.

I ran 6ga to my movable trailer solar array to the cabin. I know over kill but got a screaming deal on 6ga 4 conductor SOOW cable,

 

[HRTKD]

I used MC4 connectors from TEMCo Industrial. No problems connecting to the existing MC4 connectors on two different brands of panels that I use.

I'm planning on running 2S x3 to each of the 3 Zamp SAE ports which combine in parallel and feed to the charge controller via 8 AWG wire.

Are the three strings going to be fused between each string, either before the port or after the port?

I think I would tend to go 3s2p to avoid the need for a fuse and it also keeps the amps down and voltage up. I also would have bought larger panels to reduce the install time, but that's water under the bridge.

 

[RV Steve]

There are some non-MC4 that are cross listed for themselves and for MC4, but based on your description of your research you have probably found those and not been able to find #8. By comparison 10 and 12 are needed by a ton of panels and strings. Possibly most users of #8 are using it downstream of combiner boxes rather that directly with MC4 Y connectors.

Have you considered asking a workshop to crimp for you? This is a service that some places offer with an appropriate lead time. My solar distributor offered to arrange that for me (since I needed a bunch of MC4 to Jinko adapters). Titan Monroe might do it. Maybe some of the higher quality distributors of kits

Note that some panel manufacturers will grant warranty clearance letters for customers to remove and recrimp without losing the warranty.

I don’t have experience beyond just parroting the NEC and product listing rule book, and I actually would only trust a forum to be able to speak to what was found after a few year inspection. Because I don’t know what evidence I would be happy with that it is OK, based on random dog on the internet. And there have been forum members that found melted connectors from mixed installs, completed before the listing requirement came in.

Thanks for the input. Windy Nation sells premade and custom length 8 Awg cables with "Staubli or equivalent MC4 connectors". I will most likely use them. A forum member posted a video of a failed connector (Windy Nation to Renogy) but mentioned he had disconnect it several times. That's why I posted looking for others experiences.

 

[RV Steve]

Thanks for the input. Windy Nation sells premade and vuston

I used MC4 connectors from TEMCo Industrial. No problems connecting to the existing MC4 connectors on two different brands of panels that I use.


Are the three strings going to be fused between each string, either before the port or after the port?

I think I would tend to go 3s2p to avoid the need for a fuse and it also keeps the amps down and voltage up. I also would have bought larger panels to reduce the install time, but that's water under the bridge.

Each string will have a 10 amp inline MC4 fuse; stated in my original post. I prefer 2S3P over 3S2P to minimize potential shading impacts. The AC on my RV roof will shade panels early and late in the day.

 

[740GLE]

You have/or are getting a pair of 150v60a MPPT, but are only planning on running 2s3p at 50v to it?

Why not do a 3s2p? Get that voltage up higher, no need to duck around with 8awg if your running say 75v and ~10a to the MPPT. Heck you could prob do 4s2p without concern for the 159v high limit depending on VOC of the panel.

 

[zanydroid]

Windy Nation sells premade and custom length 8 Awg cables with "Staubli or equivalent MC4 connectors".

Are they a high end enough reseller to respond to pre purchase questions about which specific connectors they are using?

 

[RV Steve]

Are they a high end enough reseller to respond to pre purchase questions about which specific connectors they are using?

I emailed Windy Nation a few weeks ago and asked if they had heard of any compatibility issues between the MC4 connectors they use and other brands of MC4 connectors. I also asked what brand they use. They replied: "We use a mix of Staubli and other brands and have never received any complaints regarding incompatibility". I have also looked at their webpage where they sell MC4 connectors and no brand is stated. However, on their premade solar cable page it does say they use "WNI PV solar connectors". Perhaps WNI stands for Windy Nation Inc??? I would assume they must use Staubli on their 8 AWG solar cables since that's the only brand of 8 AWG MC4 connectors that I have been able to find. But they could use "other brands" on the 10 and 12 AWG solar cables they sell.