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diy solar

Noob question: parallel and series set up for 4 panels

Also, just so it's clear (I am a noob), I connect 2 x 100W in series, and get (20V x 2) = (40V & 5.7A) on my 2S.
I then connect 2 x 100W in parallel, and get (5.7A x 2) = (11A & 20V) on my 2P. I then pigtail it into a 3 way union, feed it down 1 8AWG cable to my Victron which sees 40V11A? I am staggered at the possibilities. I have either done series, or parallel, but never combined. This solves a whole bunch of other problems. I am proliferating arrays, as the solar system expands.

I built my system to be reconfigurable. It has to change purpose, and it all comes together on busbars and Anderson quick connects. My batteries are in Minn-Kota boxes, that join the busbar via a quick connect. Some days a combination of 100Ah batteries works with a 400W, 200W, 100W array, depends on the need. In theory a 5 x 100Ah parallel bank could see 4 x 100/30 Victrons feeding from 1,600W of panel, tho that arrangement has never seen the light of day.

Yeah, I know I have let the BMS reach an equalibrium, but usually I have days to let things settle before they transmogify.

I'm using Renogy 100W flexis for the panels. I build a homebrew rack that holds 2 x flexis. Very stable, seen 30MPH winds and flash flood rain, so environment seems to not be a problem. Most days a flexi is not on a rack, sits in a shed with others. I wanted 'wireless electricity' for remote forays. Come preetty close.
 
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It further dawns on me I probably have that answer. What I will get is the lowest common denominator from either 2S or 2P. I will get the 20V of the 2P, and the 5.7A of the 2S. So, a bit short of optimum for 400W of panel. Or, I run another cable, and use an additional controller (?).
 
Many Ways to combine them. Y Cables are easiest:

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But the MC4s are limited to 10 AWG, but you can butt splice 8 AWG into that. To use larger gauge wire there’s the combiner box like this MiidNite SOlar:
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Once you have an MPPT controller, the possilities to combine panels into series, parallel, or series parallel are daunting.

EDIT: I do not see a reason to go with an additional controller.
 
I then connect 2 x 100W in parallel, and get (5.7A x 2) = (11A & 20V) on my 2P. I then pigtail it into a 3 way union,
Wait, if you're trying to make 2S2P as was suggested this is all wrong.

You take 2 panels, connect the + of one to the - of the other. Do this for the other pair. Now you have 2S (2 panels in series (twice)).

Then you combine the + of one string to the + of the other string (with a Y cable for example). Connect the - to the - with another Y.

This give you 2S2P. Your array will be 2x the volts (from the series) and 2x the amps (from the parallel).
 
Excellent. Right now I am running a training grid built with scratch and dent discount panels where I test racks, controllers, busbars, everything. It took two pairs of pigtails, and a set of Y connectors, and it was live. And, I sprang for Blue Tooth on my MPPTs, so I could watch myself on TV.

Yes, this is what I want.

Thank you, thank you, thank you.
 
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Excellent. Right now I am running a training grid built with scratch and dent discount panels where I test racks, controllers, busbars, everything. It took two pairs of pigtails, and a set of Y connectors, and it was live. And, I sprang for Blue Tooth on my MPPTs, so I could watch myself on TV.

Yes, this is what I want.

Thank you, thank you, thank you.
If you are looking for bargain solar panels, Santan Solar has a lot.

 
the MC4s
But the MC4s are limited to 10 AWG, but you can butt splice 8 AWG into that.

You can get 8ga MC4 connectors, I think?!! I’ve for certain got 8ga solar panel to SCC cables (I know, overkill) and I’ve for sure crimped MC4 ends on it…I thought I I ordered 8ga MC4s.

using Victron MPPT 100-30. Is it possible for one of those to get stressed?

If you exceed the specs on any equipment it will stop being equipment and become electronic waste.
 
You can get 8ga MC4 connectors, I think?!! I’ve for certain got 8ga solar panel to SCC cables (I know, overkill) and I’ve for sure crimped MC4 ends on it…I thought I I ordered 8ga MC4s
The 8 AWG MC4 cables I saw already had wire installed in the cables, so would still need to connect it to something to finish the connection to the SCC.

I did not find any 8 AWG MC4 cables long enough for the run I was doing.

Also, the MC4 cables still have a 30 amp limit, just like the 10 AWG wire. 8 AWG can go higher, but not the connector.

I don’t think the 8 AWG is overkill especially for the lower voltages with amperages approaching 30 with longer runs. Voltage loss can be an issue and I wish I found an MC4 with a thicker cable, but I ended up butt splicing 6 AWG to prevent voltage loss. I probably loose more at that crimp than had I just left it 10 AWG, but no easy way for me to test that now.

The 10 AWG limit on the MC4 seems to be a design to limit amperage to 30 amps. For my build that exceeded the 3% loss I was trying for, so to get less than 3%, at least on paper, I butt spliced the thicker wire. I’m sure I’m not the only one who would like to see MC4 in a 6 AWG configuration, but would keep amps underneath 30 amps.
 
took two pairs of pigtails, and a set of Y connectors, and it was live
took two pair
FWIW I run 4 100W 2S2P
The other morning in the sun hitting both pair oriented 90* from horizontal I was at 19.x Amps at 14.2V with an epever mppt
I was quite Impressed - hadn’t seen that before cuz I’m usually not there that time of day. Imagine if they were tilted at the correct angle!!
 
Also, the MC4 cables still have a 30 amp limit, just like the 10 AWG wire. 8 AWG can go higher, but not the connector.
I went to 8ga for overactive ocd imaginations of efficiency :D purposes

IIRC I bought 8ga solar wire from windyNation and crimped my own ends (might also have been windyNation? at that time? Might have been another brand?)

I do have 10ga ends in case panels want them.
 
Not sure those are MC4 Connectors. I don't see MC4 in the description anywhere. The reviews give me the impression they are compatible, but I'm nto sure they plugged a MC4 to this connector. The reviews say there is a lock you can't undo and will need to destroy to disconnect. I may get a mixture of sizes of these for a project.

There's an Amphenol H4 connector available in up to 8 AWG that I think is rated for 45 amps or more. This can plug into MC4 and there's some debate about whether this is correct or not. Seems that the manufacturer wants you to only use there connectors, but many people said they've connected the H4 and MC4 connectors interchangebly.

https://www.amphenol-industrial.com/h4-8awg-news

You can still purchase these with a 8 AWG google search, but I don't see them listed anymore on the product page pnly 14 AWG, 12 AWGG and 10 AWG:


So, although THese H4 connectors (which I think is what the link is) will plug in a MC4 connector, for those that need it, it is not a UL connection. My RV probably won't matter, but if I did a home build, since I live in the 5th biggest city in America, I would probably need a UL connection. I don't know if an inspector would come out or not or just look at blue prints even if I did.

 
https://www.amazon.com/dp/B07TQ5H6M7/ref=twister_B07TLXSLZS?_encoding=UTF8&psc=1
And, I stopped trying to use a crimper from MC4. I found I could do far better and faster with just a simple pair of needle nose pliers. I have had zero failures doing it that way.
The solid copper ends claim 50A but description says 10ga wire… so 30A

You aren’t doing a proper crimp with needle nose pliers, never mind “far better.”

There’s probably only one “proper” MC4 crimp (hex swage) though I do have a “B” crimper that I use that neither distorts the terminal nor allows any movement. Not lab tested but it’s wicked tight. Both these crimps swage the ferrule and I defy anyone to pull either of them out. The B actually isn’t faster and while I can start with one hand (convenient) it takes two hands for me to finish it. The hex tool is big and doesn’t slip in my pocket, takes two hands to operate to start but it bottoms the die first try every time.

Crushing the ferrules with needle nose is neither 100% contact nor is it more than a friction fit. Maybe it “works” but I wouldn’t do it.
 
The solid copper ends claim 50A but description says 10ga wire… so 30A

You aren’t doing a proper crimp with needle nose pliers, never mind “far better.”

There’s probably only one “proper” MC4 crimp (hex swage) though I do have a “B” crimper that I use that neither distorts the terminal nor allows any movement. Not lab tested but it’s wicked tight. Both these crimps swage the ferrule and I defy anyone to pull either of them out. The B actually isn’t faster and while I can start with one hand (convenient) it takes two hands for me to finish it. The hex tool is big and doesn’t slip in my pocket, takes two hands to operate to start but it bottoms the die first try every time.

Crushing the ferrules with needle nose is neither 100% contact nor is it more than a friction fit. Maybe it “works” but I wouldn’t do it.
You may wish to check out the links posted here:

Post in thread 'PV stripper and 8awg crimper, success!' https://diysolarforum.com/threads/pv-stripper-and-8awg-crimper-success.28309/post-339289

They also have 8 gauge connectors. They are not cheap, but seem to be worth it. I am certainly going to invest in the 8 gauge wire stripper.
 
am certainly going to invest in the 8 gauge wire stripper.
Geesh.
I do like that stripper but I’m not in the mood to drop $500 for them right now (plenty of strippers and crimpers already, some even good!)
Is that Rennsteig brand on the 8ga MC4s? The “staubli” mentioned are like $18 each but the description is so botchy I’m not buying them (no mention of gage on amazonian)
 
Geesh.
I do like that stripper but I’m not in the mood to drop $500 for them right now (plenty of strippers and crimpers already, some even good!)
Is that Rennsteig brand on the 8ga MC4s? The “staubli” mentioned are like $18 each but the description is so botchy I’m not buying them (no mention of gage on amazonian)
Well, the stripper is only $125, and just last night I stripped 26 ends of 8 gauge Ancor wire (they have some really tough insulation). I think they would be worth it.

The crimp tool, I'll probably wait on, but I will likely buy one. I have a tool problem. :rolleyes:
 
have a tool problem
Ya I hear that
Other than a lift and a tire machine I wouldn’t have to buy much to open a service garage; I would not need to buy anything to build kitchen cabinets or certain furniture.

The two tools together are almost $500. I always say I have four or five crimpers but the truth is I have way more than five, I just use only four because they do good things.
 
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