MC4 Connector Question

[HOU_Castle]

All,
I'm confused with many responses around MC4 connectors (male and female) not being fit right.
Can you all help me to understand? My understanding MC4 should be fit regardless the wire size being crimped.
I have Victron mppt 250/60 with MC4 connectors. My plan is to run 8AWG wire from combiner box to the mppt.
With that, I need to make MC4 connectors for 8AWG wire. Do you think these MC4 8AWG male/female will fit to my Victron mppt?

Thank you in advance.

 

[chrisski]

Some of these 8 AWG “MC4” connectors are actually Amphenol H4 connectors. They fit together perfectly. Each is UL rated. COnnecting the two connectors together somehow makes them not UL rated.

The 8 AWG”MC4” connectors I found on Amazon when I looked all had wire already installed and I opted not to deal with the problems like too long or too short of a wire.

Others say to use the same brand of MC4 connectors throughout your install To prevent connection problems.

Also, in my 4 Victron SCCs, the bare wire is inserted into the SCC, not MC4 connectors. So once the MC4 coables from the panels enter into the combiner box, it should just be a 8 AWG wire stripped on either end than gets inserted into the combiner box and SCC With no need for an MC4.

 

[HOU_Castle]

The issue is I need to run 70ft 8AWG wire to my mppt.
The MC4 8AWG connectors (rated 50A) are way more expensive than 10/12AWG MC4 connectors (rated 30A).

 

[Sabre36]

MC4 crimp tools are inexpensive

 

[time2roll]

Go to a solar store and get a custom cable made.

Something like this:
Need a custom length? Give us a call!

 

[chrisski]

I find measuring cables to the correct size extremely difficult, especially as wires snake their way through things. I estimated 60 feet but used 90 feet. I’m glad I did not buy pre cut cables.

I find making cables to the correct size much easier. All I needed was MC4 connectors, a short length of 10 AWG wire, and a butt splice to join this with a longer length of 6 AWG wire which connected to the charge controller.

This is the how to from @HRTKD

How To: Joining Different Gauge Wires

I have 6 AWG welding wire coming out of my solar component compartment in my trailer, joining up to 10 AWG on an SAE quick connect. The purpose of this thread is to show how I connected wires of dissimilar gauge using a butt connector. I cut the wire for the quick connect about half way. The...

diysolarforum.com

What I am going to try to do with my future builds is keep amperage below 30 and volts high enough that I only use 10 AWG for wiring from the combiner to the SCC.

 

[HOU_Castle]

I find measuring cables to the correct size extremely difficult, especially as wires snake their way through things. I estimated 60 feet but used 90 feet. I’m glad I did not buy pre cut cables.

I find making cables to the correct size much easier. All I needed was MC4 connectors, a short length of 10 AWG wire, and a butt splice to join this with a longer length of 6 AWG wire which connected to the charge controller.

This is the how to from @HRTKD

How To: Joining Different Gauge Wires

I have 6 AWG welding wire coming out of my solar component compartment in my trailer, joining up to 10 AWG on an SAE quick connect. The purpose of this thread is to show how I connected wires of dissimilar gauge using a butt connector. I cut the wire for the quick connect about half way. The...

diysolarforum.com

What I am going to try to do with my future builds is keep amperage below 30 and volts high enough that I only use 10 AWG for wiring from the combiner to the SCC.

Unfortunately, my panels are about 70ft away from mppt. I tried with 4s to increase the voltage but I got hit with shading (from 50A down to 8A). So, I'm trying to do 2s2p to minimize the shading but it requires bigger cable.

 

[chrisski]

Unfortunately, my panels are about 70ft away from mppt. I tried with 4s to increase the voltage but I got hit with shading (from 50A down to 8A). So, I'm trying to do 2s2p to minimize the shading but it requires bigger cable.

I think you mentioned 8 awg. For a run that long, 6 AWG or 4 awg would be better. Not so much for what you have now, but if you add another SCC for more power down the road.

Are you running each string to a combiner 70 feet?

You can build this for what’s best and I’m not a solar tech or engineer, but I’m still puzzled why it has to be mc4 cables with that much amperage. The combiner box I installed and the three I made were water resistant and could be installed outdoors by the panel like this:

https://www.amazon.com/Midnite-Solar-Photovoltaic-Combiner-3-Position/dp/B004XFYV8U/

And only required an mc4 from the panel and the cable got touted in through a cable gland. My model will take a thick cable perhaps 2/0.

For my RV build because of shading, I have the same problem. On the roof I have two arrays, 2s2p and 3s2p. My thing was not enough planning when I put the panels down.

 

[Bud Martin]

What is the current for each string of your 2S2P configuration?

 

[HOU_Castle]

I think you mentioned 8 awg. For a run that long, 6 AWG or 4 awg would be better. Not so much for what you have now, but if you add another SCC for more power down the road.

Are you running each string to a combiner 70 feet?

You can build this for what’s best and I’m not a solar tech or engineer, but I’m still puzzled why it has to be mc4 cables with that much amperage. The combiner box I installed and the three I made were water resistant and could be installed outdoors by the panel like this:

https://www.amazon.com/Midnite-Solar-Photovoltaic-Combiner-3-Position/dp/B004XFYV8U/

And only required an mc4 from the panel and the cable got touted in through a cable gland. My model will take a thick cable perhaps 2/0.

For my RV build because of shading, I have the same problem. On the roof I have two arrays, 2s2p and 3s2p. My thing was not enough planning when I put the panels down.

The combiner would be near (3ft) from the panels. From the combiner to the mppt is about 70ft. My Victron mppt 250/60 has MC4 connectors. I don't want to destroy my Victron MC4 connectors.

 

[HOU_Castle]

This is Victron mppt 250/60 MC4.

 

[chrisski]

I appreciate the pics. I did not realize larger Victron controllers had MC4 connectors

This is a link to the Amphenol h4 8 AWG connector rated to 65 amps.

Amphenol Industrial - H4CFE8UM - Helios H4 Solar Connector,Cable Socket,8 AWG,Helios H4,1000 V - Allied Electronics & Automation

H4CFE8UM from Amphenol Industrial at Allied Electronics & Automation

www.alliedelec.com

This requires a more expensive h4 crimping tool. This is one but not sure it goes 8 AWG.

Amphenol Helios H4 Crimp Tool with Die Set

Amphenol H4 Crimp Tool with Die Set features parallel jaws and precision ratchet mechanism for complete, even crimps. Interchangeable crimping die set.

realgoods.com

These are supposed to be a direct fit with MC4, but not approved. I only mention this again because the spec sheets I looked at for 8 AWG MC4 connectors were actually either H4 or avoided saying MC4. People have interchanged MC4 and H4 on builds when the other ran out.

 

[HOU_Castle]

I appreciate the pics. I did not realize larger Victron controllers had MC4 connectors

This is a link to the Amphenol h4 8 AWG connector rated to 65 amps.

Amphenol Industrial - H4CFE8UM - Helios H4 Solar Connector,Cable Socket,8 AWG,Helios H4,1000 V - Allied Electronics & Automation

H4CFE8UM from Amphenol Industrial at Allied Electronics & Automation

www.alliedelec.com

This requires a more expensive h4 crimping tool. This is one but not sure it goes 8 AWG.

Amphenol Helios H4 Crimp Tool with Die Set

Amphenol H4 Crimp Tool with Die Set features parallel jaws and precision ratchet mechanism for complete, even crimps. Interchangeable crimping die set.

realgoods.com

These are supposed to be a direct fit with MC4, but not approved. I only mention this again because the spec sheets I looked at for 8 AWG MC4 connectors were actually either H4 or avoided saying MC4. People have interchanged MC4 and H4 on builds when the other ran out.

I just found the US made cable supplier, which makes 70ft - 8awg cable with MC4 connectors both ends. That way, I don't need to invest the crimp tool.
Thank you for helping. My original setup was 4s that's why I bought Victron mppt 250/60. But the shading is eating my lunch, and I can't stand it. So, here I am investing in 8awg cable and combiner box.

 

[time2roll]

I hate to say I am not sure 2P2S will help with the shading. Generally I believe all series or all parallel is best unless your situation is unique.

 

[timselectric]

Should always series as many as the charge controller can handle (VOC). And then, parallel more strings of the same quantity. Up to the charge controllers limit (amp) unless, you are planning to overpanel. Then, I wouldn't go beyond 150%. Beyond that, it can be a waste of money.

 

[再生可能 エネルギー]

This is Victron mppt 250/60 MC4.

Why not removing the MC4, there must be a wire connection just behind, unless the wires are soldered to the motherboard?

A set of M16 locknut could be then used to replace the MC4.

 

[HOU_Castle]

Why not removing the MC4, there must be a wire connection just behind, unless the wires are soldered to the motherboard?

A set of M16 locknut could be then used to replace the MC4.

Sorry, I won't temper my $500 device just for $20 of installing MC4 to the cable.

 

[再生可能 エネルギー]

All,
I'm confused with many responses around MC4 connectors (male and female) not being fit right.
Can you all help me to understand? My understanding MC4 should be fit regardless the wire size being crimped.
I have Victron mppt 250/60 with MC4 connectors. My plan is to run 8AWG wire from combiner box to the mppt.
With that, I need to make MC4 connectors for 8AWG wire. Do you think these MC4 8AWG male/female will fit to my Victron mppt?

Thank you in advance.

I would be interested to know what combiner box you use, which provides 8AWG output connections, because I'm in a similar situation.

Also do you use a DC disconnect switch just before the MPPT, which accepts 8AWG ?

 

[再生可能 エネルギー]

Sorry, I won't temper my $500 device just for $20 of installing MC4 to the cable.

I was just thinking about this Will Prowse video "Victron Made Easy! Design and Communication, Step-by-Step"
where it seems that he had to remove the cover of the devices @1:42 to wire the cables to it.
But I don't know if the cover of your device had to be removed during the instalation.

How many Amp do you have on each MPPT input and how far are your PVs from your MPPT?

 

[HOU_Castle]

I would be interested to know what combiner box you use, which provides 8AWG output connections, because I'm in a similar situation.

Also do you use a DC disconnect switch just before the MPPT, which accepts 8AWG ?

I use PV Combiner Box, which has 4 Strings with 15A Rated Current Fuse, 63A Circuit Breaker, and Lightning Arrester.