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Forum Index : Solar : High power DC relay Setup.
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| George65 Guru  Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Well, I don't know about that. I just did one of the hardest and most difficult and painful things I have ever done in my miserable life which I didn't think I had a hope in hell of pulling off. I did it and did it pretty well it seems. Something I was dreading and never thought I would be able to get through but when the time came, I found a set of balls way beyond what I ever knew I had and managed something even people that had seen it all before were amazed with. Just as well for me. I would have regretted it every day for the rest of my life if I hadn't been able to do it and never forgiven myself. Maybe Henry was right in now that I have done it, I'm satisfied and kind of thinking I can achieve pretty much anything I want no matter how hard or painful. At very least it's given me the heads up i'm not completely useless, yet. Not sure that extends to mental capacity to get far with electronics but I can sure as hell pull this circuit off! I'm more electrics than electronics but this is close enough and I have already learned something very helpful I can use with other things. As stupid as it will sound to the knowledgeable, I never realised, these things are just essentially relays or powered switches. Least I can get my head round thinking of them like that!  Thanks again! |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Would like to know a whole lot more about this, like how you have it physically constructed etc. Do you have a PCB? Presume that circuit could be split in 1/2 for two separate switches? Acquired another 12 panels yesterday, so that gives me the issues of 3 banks & 2 inverter inputs. At this point I figure I've got to choose the best 2 banks based on time of & use them. Phil. |
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Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Phil have a look here this is the big brother to the circuit above. I am just finishing off a revised version of this using a Nano instead of the Uno to save space. That change has allowed for including an RS485 board for communications. The initial problems I had have been resolved and I have this controller running with 7KW of panels into a 5KW inverter. I rarely get over 5KW though due to temperature and possibly some degradation of the panels. Great thing about the extra panels is I still get to Float on all but the most cloudy days. PCBs will be available very soon see here for more details. Another option Phil is a virtual tracker where you put the panels up like a tent at 60 degrees with one side facing east, the other facing west. This will limit power it the middle of the day and each half will perform really well early in the morning and late in afternoon. My preference though is put them flat to bet the most power possible and perhaps measure the battery current and use the regulator to throttle back the current as required. I am going to add an Analogue to Digital converter to get high-resolution digital output from a shunt for this purpose. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| George65 Guru Joined: 18/09/2017 Location: AustraliaPosts: 308 |
Phil I have been playing with mismatched panels and arrays and have had no problems with them. ATM I have 2 arrays of 240W panels with 2 arrays of 175W panels in parallel. There is a 240 and 175W string on each input and it's working as it should. Due to the higher voltage, I have one less panel of the 175's than I do the 240s in the string. Loaded Voltage match isn't perfect but it does not matter. I get the proper combined output ( for this time of year) as I should and the 175's are no pulling the 240's down on output as they would if mixed in the same string. I know there is a lot of info on the net that says Don't do this and don't do that but a lot of it is coming from the POV of ideal and highroad setups for New and expensive installs, not the cheap as chips price we are getting panels for. There is also a lot of Industry self interest Bias going on. They are not as finicky as made out by a long shot and as far as panels go, In my experience, all this efficiency thing is a load of BS anyway. The things are terribly INEFFICENT no matter what you do. Another percent or few is not going to make any difference especially if your no by the book install ends up netting you more power and savings. If you are like me and are buying 3Kw of small panels for $250 with an inverter and getting $1.80- $2.50 worth of power out the things per day, then to me it's still a good deal and setup no matter how you wire them. You don't need to have a separate input for each array, easy to double them up in parallel. I have inverters with 4 inputs that only have 1 Tracker so it really does not matter how many inputs, on some inverters they are all joined internally anyway and on others it's 4 Inputs to 2 trackers. All you have to watch ( or at least I do) is not to exceed the voltage limitations of the inverter. I give that about 100V headroom and have been fine. I like the higher voltage arrays anyhow where I can do them because I think it allows the inverters to get to cut in voltage earlier and finish later Instead of having more current below threshold voltage. I am also running 2 same arrays onto the same heavy Neg lead and just running individual positives so I have 3 wires coming off the roof instead of 4. Makes things easier and cheaper as well. I also discovered one of my inverters is wired this way anyhow. The neg is internally shared and only the positives are split. Wondered why when I disconnected the neg lead I split to the inverter I was still getting full power from both arrays. Turned out they combine the negs internally anyway. I have been thinking about Mads split orientation setup for a bit and also going to play with that. I can't pump much more peak power into my wiring even with the HD circuits installed due to the current capacity of the meters but I still want more total KWH. Problem is generation time is limited to about half if that, of usage time. Smoothing the power and getting a more even input instead of ramping up and falling off may be helpful and allow me to make the most of secondary roof space.... Although I'm getting well into that now too! I am using the Voltage monitoring relay on the hot water heater and have adjusted that to suit peak output more. This is good in absorbing the power at it highest point and flattening the peak feedback a bit. Be interesting to see what my output today is after dropping that mongeral Tree that I discovered was causing shading on the array on the shed in the morning and the array on the house in the afternoon. I reckon that's a min of 3 extra hours direct on my panels. Did 20 KW combined on those 2 arrays yesterday and today looks more Hazy so if I see anything above that, I'll be real happy. Amazing how fast some Trees ( weeds) can grow and how fast the sun changes it's height in the sky! |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
If you have a smartphone Google Sky maps is really good for checking the sun position on any day. You can pick a date and fast forward through the day pointing your phone at the sky it shows you the position of the sun. So if you play it at 1 second = 1 hour in very short space of time you can see the full arc of the sun from where ever you are standing. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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solarwind Regular Member  Joined: 03/02/2008 Location: South AfricaPosts: 51 |
I had two arrays feeding the one input on an IMEON 3.6 Hybrid Inverter. The North facing array consisted of 9 x 310 Wp panels, three strings of three, positives paralleled at the DC panel below, via the usual string fuses etc. The other array was facing due West and had the same configuration with 9 panels, but they were only 180 Wp panels, so the voltage output was lower of course, but did not matter much due to the fact that it did never peak at the same time as the first array, due to the difference in orientation. The Negatives of each array fed into diodes with the anodes together and a cathode for the negative of each array. This provided isolation between arrays to prevent back-feed from either array into the other depending on the sun's position. They worked very well and great parts of the day they successfully shared the load (inverter). I am sure that a lot of people will tell me that it is wrong, but it worked.  Due to unfortunate personal circumstances, I had to move and the whole system was sold by the other party in the relationship!You don't have success until you've tried it! |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Interesting, Will the UNO one still be obtainable? My initial thoughts, being vague on Arduino code was to replace the UNO a CGMicroboard2, basically an Arduino pin compatible Micromite; just cause I'm more at home in that language. There are a few MM's that have a Nano form factor, just not sure how well pin outs match. Is there a schematic posted somewhere, had a brief look & didn't see it. Phil. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
https://www.rictech.nz/products/20/MicroMite-Explore-28-module  I dont know about the pins, I will have to fit a breakout board shield to use a wemos D1 mini you could look at the PCB pdf or find a nano pinout list. source I'm confused, no wait... maybe I'm not... |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
There are detailed pictures of the PCB in the Mad/Oz GTI regulator thread in electronics, there is no schematic. I have no desire to use mites, I understand Arduino's to a point but have no clue about other microcontrollers. The old version of the regulator uses a special version of the UNO with extra rows of pins, the new version is set up for the Nano to save space. I have added a lot more functionality to it which I am still working on. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Understand that completely, & likewise I'm relatively confident with the Mites & basic, but get somewhat lost with Arduino code, particularly when libraries are involved. Can sometimes translate between the two other times not. Module posted above is the same form factor, but some of the pins could be incompatible, like the location of Power, Gnd, Reset & Tx/Rx. That could be sorted with a sandwiched pin swapping board. Phil. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I will be supplying code for the Arduino so you would only need to change a few parameters. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
I modified my solar power switching to the above way and it works a treat  .Pretty simple too, the isolated 18V power module did not take any more room than the two AC SSR's it replaces in my little enclosure. I use a little 12V relay to switch the 18V DC via the programmable voltage sensing relay, to turn the Mosfet ON or OFF. So, thanks again for posting this Gary. Klaus |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
You could also use a A3120 Isolated Driver IC, then you just need a few milliamps to control it. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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