Wiring Panel to Panel When There is Distance

[AgroVenturesPeru]

Let's say I want to wire Panel A to Panel B to Panel C to Panel D in series and the middle of each panel is a distance of 4 meters apart,
Panel A has a negative (female) MC4 integrated, but it will not reach all the way to the positive (male) MC4 of Panel B.

What is the proper order of components?
This is what I'm thinking:

[Panel A's negative (female) MC4] - [male MC4, 2meters of black cable, female MC4] - [male MC4, 2meters of red cable, female MC4] - [Panel B's positive (male) MC4]

Do I have to use 2m of black cable and 2m of red cable? Would it be a problem if I used 3.5m of black cable, and only 0.5m of red cable? The above layout sounds like it will use way too many MC4 connectors.

What would happen if I did the following?

[Panel A's negative (female) MC4] - [male MC4, 4meters of black cable, female MC4] - [Panel B's positive (male) MC4]

 

[Diysolar123]

the distance is an issue based on current draw and the resistance of the wire you are using (and of course do not short out the panels hehe).
the "normal" MC4 solar cable is 10awg, you can also get 8awg...
your wire distance across the series panels would be around 12meters (a->b b->c c->d) ???

so using a typical voltage drop calculator you can check your wire resistance:

Voltage Drop Calculator

This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.

www.calculator.net

you can play around with what voltage drop you are comfortable with. While each connector does add a bit to the resistance of the overall wire length, the current involved and the wire guage is probably much more important.

I have a milliohm meter and just measured the resistance between two terminals on three MC4 1M to 2F connectors I put in series; it was around 1m ohms so they are meeting the "spec" of less than 0.5mohms mating resistance. The resistance of just 8awg copper wire is around 0.6 to 0.7mohms/ft so do not worry to much about the connectors.

 

[AgroVenturesPeru]

Unfortunately, this did not answer my question. My question has more to do with how to physically wire each panel together.

This wiring uses 4 MC4 connectors between each panel:

[Panel A's negative (female) MC4] - [male MC4, 2meters of black cable, female MC4] - [male MC4, 2meters of red cable, female MC4] - [Panel B's positive (male) MC4]

This wiring uses 2 MC4 connectors between each panel:

[Panel A's negative (female) MC4] - [male MC4, 4meters of black cable, female MC4] - [Panel B's positive (male) MC4]

Well, I'd prefer to go with the second strategy, obviously, as it uses less MC4 connectors, but I don't know if it's correct

 

[MichaelK]

It might be more cost-effective to just buy a length of 10AWG wire, and a bag of MC-4 connectors. You cut the wire to the custom lengths you want, add on the connectors, and complete the wiring.

Because this is a serial connection, one side being longer than the other side is irrelevent. Only the resistance of the total length, and the total number of connectors is important.

BTW, once you've gotten 2-3 panels in series, the overall voltage drop is so low it's not worth trying to measure.

 

[AgroVenturesPeru]

[Panel A's negative (female) MC4] - [male MC4, 4meters of black cable, female MC4] - [Panel B's positive (male) MC4]

So basically, what you're saying is that my second strategy is correct?

 

[MichaelK]

So basically, what you're saying is that my second strategy is correct?

Yes. When you ready to disassemble the MC-4 connectors for the first time, draw a quick sketch of how the little parts go together. They need to be assembled in the right order/direction to insure a watertight connection.

The MC-4 connectors are designed to be crimp-secured in place, but I'm anal, so I solder them as well.

 

[AgroVenturesPeru]

Yes. When you ready to disassemble the MC-4 connectors for the first time, draw a quick sketch of how the little parts go together. They need to be assembled in the right order/direction to insure a watertight connection.

The MC-4 connectors are designed to be crimp-secured in place, but I'm anal, so I solder them as well.

Hey man, I bought an MC4 crimper just for this purpose. It cost me $100. It's pretty heavy duty, and seems to work pretty well. Actually maybe too well. It looked like it almost broke one of the pins. Basically flattened it like a pancake on top of the copper stranded wire.

I know that male pin goes with female connector, and female pin goes with male connector. There's a good diagram on explorist life. Is that what you had in mind?

https://www.explorist.life/wp-content/uploads/How-To-Crimp-MC4-Connectors-5-1024x1536.jpg.webp

 

[Diysolar123]

Unfortunately, this did not answer my question. My question has more to do with how to physically wire each panel together.

This wiring uses 4 MC4 connectors between each panel:


This wiring uses 2 MC4 connectors between each panel:


Well, I'd prefer to go with the second strategy, obviously, as it uses less MC4 connectors, but I don't know if it's correct

sorry, I was answering this part of your original question as it seems you were worried about too many connectors:
"The above layout sounds like it will use way too many MC4 connectors."

the short short answer would be...the number of connectors does not matter in your setup.
Pick a layout that is easy to remember and assures you do not confuse any of your "positive to negative" daisy chain of series connections.
Labeling MC4 connectors is very important as there is no "fixed" plus or minus like there is in an XT90 connector.