Soldering Solar Connectors (4K)

Today I need to put some MC4 connectors on the cable of some new solar panels. This is a video of what I have found works well for me.
This application is low voltage (12 to 24 volt) to run a DC brushed motor water pump.
Related Article: Home Solar Power Problems - They’re Not What You Think
/ home-solar-power-probl...
WARNING: Solar panels generate electricity. Electricity dangers include: fire, shock, burns, and electrocution.
Soldering carries risks of poisoning, burns, shock, fires, etc. If you do not know, learn first or do not do this.

[@tsbrownie]

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[@jbarber]

Looks pretty good, sir. One thing I would like to mention is that you should tighten the retainer nut to the point where there is no longer any gap. Thanks!

[@phuketexplorer]

Doing that crushes the silicon seal inside the cap. They should be tightened until resistance is felt.

[@ExposingTruthChannel]

Very clear explanation, good closeups. Thanks. It should cautioned to not use acid-core solder, which can leave a residue that causes corrosion. Use only rosin-core solder for electronics or electrical connections.

[@marcfruchtman9473]

Great quality video with excellent close up views. I was testing to see the "depth" that the metal male and female Crimp Contacts would go into the plastic and when I look at the amount they go in, it looks far short of where they should settle. I guess part of the reason is that I am not fully pushing them in until I hear a "click". I was hoping it would seat at full depth but didn't want to push them in until I do the soldering to test that theory. Nevertheless, I took the risk, and it does seat all the way in. Once you seat them, it is nearly impossible to remove it.

[@tsbrownie]

That's the truth, they really lock in there tight!

[@phuketexplorer]

Beautiful video and well presented... but... Mc4 connectors fail due to aging of the connecting pins and sockets, inside the plastic moulding. The first signs are of the plastic becoming distorted and burning. If this is happening on a roof top, out of view, the results can be catastrophic, depending on whether the panels are connected in parallel or series. The answer is to do away with ALL of them, crimp and solder cables together and then insulate them with shrink fit pvc sleeves.

[@ThatGuy-dj3qr]

Excellent video. Extremely clearly explained and shown. Thank you

[@tsbrownie]

Thank you, I'm glad you like it.

[@ameic]

I saw in another video the end caps should be screwed until they are completely flush to aid in the water resistence, is that true?

[@tsbrownie]

It depends on the brand of connector. Some will screw all the way in, others will not. It just needs to squeeze the rubber ring around the wire to make it water-tight.

[@ameic]

@@tsbrownie I thought as much, when I was ordering mine some came with a tool indicating to me much force was required for proper fitment.. must have been that brand specifically. Thanks for the tips, went together flawlessly.

[@panospapadimitriou3498]

destroying my only spare one pair of the pack made me come here . thanks !!!!!! trully helpfull!!!!

[@tsbrownie]

Great to hear!

[@peteypops]

Surely, the plug gender does not necessarily indicate exclusively positive or negative as the connecting wire must have the opposite gender plug?

[@tsbrownie]

That's exactly right, and it's a danger. On the panels the plugs are marked plus and minus, but if you have an "extension cord", you are using negative plugs in the positive line and vice versa. That can lead to confusion leading to shorts if one is not paying attention.

[@CollinBaillie]

Can you do a video on the EVO2 1500v 50A 10mm2 connectors?

[@FoodOnCrack]

I have never seen any manufacturer of mc4 connectors, or in the manual of the inverters call for soldering. Only crimping with an appropriate F crimp and torque to spec with a torque wrench.

[@tsbrownie]

In theory it's not required, but over time the different metals of the connector and wire will corrode increasing resistance. Even when new, each junction adds a bit of resistance and one side of the connector has 2 junctions or 4 per connection; soldering "eliminates" 2 of those junctions per connection. Most of my systems are small, portable things that run on 12 volts, and at such low voltage, even 4 ohms additional is a lot of lost power, and that resistance will only increase over time. So it's true, they don't call for soldering, but if your system is in place for 20-25 years, the seals start to break down (or were never right), you have galvanic corrosion, use lower voltage, have more extreme weather conditions, ... then soldering will give you the most for the longest out of your system.

[@bialy100k]

People solder, twist wires in fingers, add own insulation or even grease connections. It looks perfectly clean when is done. After 10 years wire corrode (they "forgot" to clean flux - as here), size or have bad contact due wrongly crimped metal over twisted wires. And is a "problem". Best is a to go Staubli (MC4 designer) video :)

[@declaracioneside]

what is the key name to disconnect this type of mc4 connectors ?

[@tsbrownie]

I don't understand.

[@ameic]

great video!

[@donfrank4429]

you should of talked about the solder , what size etc

[@tsbrownie]

I have videos specifically on solder, but the summary is to use a good quality electronic solder (rosin flux core is most convenient). Size is not important from a technical standpoint, but from a cost standpoint the fine stuff is higher and practically it is more fiddly to work with. Kester makes a good solder and is available at hardware stores. Do NOT use acid flux under any circumstances! It is made for steel and will eat away copper wires and fittings.

[@surenbono6063]

..is there any way to pull it out again after lock..? ..I want to add a dc voltmeter in parrellel..

[@tsbrownie]

Which part do you mean? The plastic plug can be disconnected by pushing in on the locking ears. The wire can be removed with the ferrule with a lot of effort. BUT, I won't recommend you do that. These systems can carry hundreds of volts (mine is over 300). If I needed a meter, I would wire it in using the correct plugs / connectors, or I would wire it in inside the junction box. Safety first!

[@surenbono6063]

@@tsbrownie ..they should make a ceramic ones..the current mc4 can't handle heat very much..anyway I simply pulled it out with force so I can add a wire for the voltmeter and also a regulator for USB fan...I'm cooling a micro grid tied inverter for fun ..it used to be outside..fear of being stolen..

[@tsbrownie]

@@surenbono6063 Ceramic would be interesting. I put mine on the roof, hard to steal! ;)

[@surenbono6063]

@@tsbrownie ..today I discovered that cooling the inverter yield more wattage like 25%... By calculation it's 2kwh daily target..but I did 2.5 kWh on 2x72 cell 36dcv 8A..minus the table fan 40wh and fixed the wifi range gtb-600..and my neighbourhood is not that save..some steal metal for scrapyards..

[@tsbrownie]

@@surenbono6063 Interesting.

[@NAZinfo]

Tku brooi😍👍

[@tsbrownie]

No prob.

[@jakelong7756]

Thanks for this!

[@tsbrownie]

Sure thing!

[@WiSeNhEiMeR-1369]

? is soldering really NECESSARY ? COOP ...

[@tsbrownie]

It depends. If you want the lowest resistance over the longest period of time, soldering is a good thing. Will the system work without it? Yes.

[@hebdomatical]

I'm sorry for being so...... but, you need to crimp before soldering. Soldering is fine, but crimping is all you need on these connectors. Get the proper tool!!! So much easier, and faster. Otherwise, generally a good video.

[@theoldhobbit3640]

@@bialy100k I have 4 MC4 connectors to re-connect due to a slight mishap, so I will be soldering the connectors as I am not paying out for a special crimp tool that I will unlikely ever need again. I know that I may be revisiting these connectors in a few years time, but at my age, it probably wont be my problem 😅🤣

[@markpalacio9899]

Thank you for a very well explained process. Your close ups are the fantastic for showing the proper length of the wire. I have a Haisstronica crimper which just did not work so well I thought it was the right size but I'm not sure it did not work so well in and of itself. I have ordered a new crimper which has a curve in the teeth so I hope that works but soldering is something I have done in the past and after viewing your vid feel confident I can achieve a similar result! Keep up the style you have a knack.

[@tsbrownie]

Thank you. My personal experience, for what it's worth, is that weather is a bear. Over time it will attack any electrical connection. Crimped joints are OK in a protected environment, like in a car, house, computer, ... but in the wild they breath in and out humidity that will corrode the wire/connector interface. Solder won't let that happen. I've been working on a video about that for a couple years, but the bottom line is to show the number of connections in my solar array (wire to connector, connector to connector, then connector back to wire; all that x 2 per panel) and if we assume each connection loses only 1 ohm per, it's a huge additional loss from resistance (especially at lower voltages). In my system that would add 50 ohms, about 40 ohms of that would be unnecessary. In my 12 v camping systems I'm fanatical about soldering and using anti-corrosive compound because 40 ohms loss would be bad.

[@kareljansen3992]

Hey, i have a question. I soldered mine before watching the video, I'm a car mechanic and i now hot to solder and used a torch not a electric one. But now I'm in Norway and the panel starts malfunction, puts out 20 volts without connecting anything but 4 after I connect regulator, now the day the panel died because the solder makes a resistance that could kill the panel,... No guarantee. But how can it be that that would kill a panel ? Hitting it a few times I found out makes it work again until some drive vibrations and than it's bad again, can you tell me if you know of that kind of isseu ?

[@tsbrownie]

I am not sure if I understand the problem. You used a gas torch? If you put the flame directly on the wire joint, that will not work well. It oxidizes the metals in the joint and the solder. A bad joint can give low voltage and an intermittent connection. If you heated the panel or put too much physical stress on the connection, it could be damaged. If you make a video, post it on KZbin and send me the link, I will look at it.

[@DanBurgaud]

I have this MC4 connector version. very difficult to disconnect

[@tsbrownie]

Yes they are. You have to make sure you squeeze the ears all the way in, then pull on the plastic part (not the wires). The good thing about them is they seem to last a long time and are weather proof.

[@bushtuckaman]

My mc4 connects are corroded and I need to clean them. Is there a household liquid that I could used, then rinse them and dry them out before reconnection? Im in an off grid situation and am currently getting zero Watts. I can see the solar voltage bouncing around on the MTTP so think its the 2 conections between my 2 panels and controller, as these get disconnected amd reconnected several times a year! I have no crimping tools or specialist cleaning liquids. I was thinking of maybe a quick lemon juice dip, then water rinse to neutralise and dry. Help needed please.

[@tsbrownie]

To be honest, I've never run into that. Did the o-rings break down? How'd water get to the connections? Of course, before you try to clean them, you should ensure there's no power present!!! I don't know about yours, but my systems 300 v with enough amps to fry a person. Leave a comment here if you find a good method so we can learn!

[@bushtuckaman]

@@tsbrownie It's 2 x 375w panels in series. Dark here currently so was going to disconnect the panels and have a go at cleaning the mc4's. I think water ingress has occurred while disconnected for 6 months over the summer. The system has been running for 2 months and then yesterday I got no wattage yield from the panels. My battery is running down so I need to get it running asap 😬 Thanks for the help

[@chicamepa]

Thanks!!!

[@info3796]

Thank you, very good explanation, very useful!

[@tsbrownie]

Glad it was helpful!

[@ameic]

only suggestion i have is mentioning which side of positive u need to put each gender on, i put it on the lead going to the battery but it should have been on the solar side. As far as i can tell it doesnt matter as long as they are oposite but thought it was worth mentioning for people following at home.

[@tsbrownie]

I say in the video that there is a + and - imprinted on each connector.

[@cdnjeepoverland]

@@tsbrownie that’s not what he means - the positive female goes on the solar side, not the battery side is the point they’re trying to make. If you were to use the female positive on the battery side your connectors would be inconsistent with other attachments etc.