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  • Beginner Working on a Self Install

    After years of thinking about it, I finally decided to take the plunge. I've purchased nearly all of my equipment, which consists of 24 Jinko 255 panels and SMA SB-240 micros, and plan to build an elevated, stand-alone structure from pressure treated lumber. I haven't found much of any discussion about these micros in particular on here, so was interested to hear from others who may have experience with them. It appears that they were never very popular, and now with DC optimizers are falling to the wayside. I'm completely fine with that, as I was able to purchase all 24+cabling+the required SMA multigate for ~$1,300. I'll be squeezing the "pergola" in a somewhat wooded area in my backyard, so I may experience partial shading at times, especially during low sun angles.

    The question I have at the moment, is exactly how I'll need to connect the multigate for network connectivity? I am using the MG-X2E model, which uses 2 multigates and does not come with a pre-installed network hub. I have already installed an extra 3/4" conduit out to where I'll be installing the system, but haven't looked into exactly what I'll need to connect it (single or double Cat5) or if there is some type of wireless add-on device that would be easier than pulling and wiring it up? I only know enough about IT stuff to be a little dangerous, so any advice would be appreciated.

  • #2
    Originally posted by brant2000 View Post
    After years of thinking about it, I finally decided to take the plunge. I've purchased nearly all of my equipment, which consists of 24 Jinko 255 panels and SMA SB-240 micros, and plan to build an elevated, stand-alone structure from pressure treated lumber. I haven't found much of any discussion about these micros in particular on here, so was interested to hear from others who may have experience with them. It appears that they were never very popular, and now with DC optimizers are falling to the wayside. I'm completely fine with that, as I was able to purchase all 24+cabling+the required SMA multigate for ~$1,300. I'll be squeezing the "pergola" in a somewhat wooded area in my backyard, so I may experience partial shading at times, especially during low sun angles.

    The question I have at the moment, is exactly how I'll need to connect the multigate for network connectivity? I am using the MG-X2E model, which uses 2 multigates and does not come with a pre-installed network hub. I have already installed an extra 3/4" conduit out to where I'll be installing the system, but haven't looked into exactly what I'll need to connect it (single or double Cat5) or if there is some type of wireless add-on device that would be easier than pulling and wiring it up? I only know enough about IT stuff to be a little dangerous, so any advice would be appreciated.
    from the installation manual it sounds like multigate comes with single Ethernet socket so you have 2 choices: either run 2 individual Ethernet cables between your multigates and your home router or install small 5 port network switch (you need only 3 ports but 5 is most commonly available) next to multigates, plug their Ethernet cables into the switch and run single Ethernet cable from the switch to the home router.
    Last edited by max2k; 09-01-2017, 10:59 AM.

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    • #3
      Originally posted by max2k View Post

      from the installation manual it sounds like multigate comes with single Ethernet socket so you have 2 choices: either run 2 individual Ethernet cables between your multigates and your home router or install small 5 port network switch (you need only 3 ports but 5 is most commonly available) next to multigates, plug their Ethernet cables into the switch and run single Ethernet cable from the switch to the home router.
      or get a set of these dual port TP-Link PLC
      https://www.amazon.com/TP-Link-Power...ort+tplink+PLC
      OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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      • #4
        How long is your run from the router in the house to where you'd connect to the equipment?
        There's a limit of 100m (328ft) for cat5 or cat6.
        And even at less than that limit you may still have problems with noise, etc.

        If it's only a 100ft run, I would just run 3 ethernet cables (using ones rated for getting wet)
        3 cables because then you don't have to do another cable pull if one of the two cables fails.

        wifi or powerline probably can work - but IMO they are more likely to have issues than a simple CAT5 line.
        And you already have spare 3/4" conduit in place, so pulling it shouldn't be difficult.

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        • #5
          I think you can purchase shielded ethernet cable..

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          • #6
            Originally posted by Murby View Post
            I think you can purchase shielded ethernet cable..
            He is talking about the distance.
            Though if you can lock the speed down to 10mbs you can go much longer distances
            OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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            • #7
              Originally posted by ButchDeal View Post
              He is talking about the distance.
              Though if you can lock the speed down to 10mbs you can go much longer distances
              I am talking about distance.
              But having a reliable connection will be affected by both EMI and distance.
              shielded cable will reduce the EMI - so could help you to get a little longer distances.
              But mostly I'd be worried about total distance - since this is going to a free-standing structure away from the house. So the distance could be 50 feet outside and 10 feet inside (very doable with CAT5) - or could be 300'+ outside and another 40' inside. (Might get that far with 10mbs and good cable and a good hub - but might not. At that distance I'd seriously look at having a plan B, like a repeater or using a wireless connection)

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              • #8
                Originally posted by foo1bar View Post

                I am talking about distance.
                But having a reliable connection will be affected by both EMI and distance.
                shielded cable will reduce the EMI - so could help you to get a little longer distances.
                But mostly I'd be worried about total distance - since this is going to a free-standing structure away from the house. So the distance could be 50 feet outside and 10 feet inside (very doable with CAT5) - or could be 300'+ outside and another 40' inside. (Might get that far with 10mbs and good cable and a good hub - but might not. At that distance I'd seriously look at having a plan B, like a repeater or using a wireless connection)
                Cat level and shielding have little to do with it. It is a timing issue for gigabit Ethernet. Twisted pair gigE is not able to handle greater distance due to timing factors in the low level protocol. Ne level of shielding is going to help that, but 10 Mbs will handle longer distances easily. I have done it with crappy telephone dry pairs.
                Also hub would be a bad choice, you need a switch.
                OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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                • #9
                  Hi bran.

                  Your custom lumber based ground mount most likely will need to be permitted, better have a chat with the local building dept since without a permit most power companies will not give you permission to operate. Many building departments will want to see enginnering on your setup so your panels do not become a flying sail taking out your neighbor in a big storm. Your interconnection will need to follow both the NEC code and requirements from the PoCo.

                  Since your running micros from that ground mount, a good goal to hit is to keep total AC losses from the service panel to the furthest micro to 2% or less to help prevent nuisance inverter tripping. Your inverter manual will give you what they suggest. Carefully compute your losses from wire resistance taking into account all cabling and don't be surprised if you need to upsize to met that goal. Along with that, better check what your local building department wants for burying depth and assuming you need a permit how they want inspections (do they want to see the unburied trench, do they want schedule 80 exits, etc).

                  Now about the network at your ground mount. You have many options open to you. You can run CAT6 cable in that 3/4" conduit and unless you are over 300' it will work great. I would suggest water rated shielded cat 6 (usually this is underground direct burial cable) but the truth is - from a code point of view - you can run whatever for low voltage communications. However most indoor CAT 6 cable has a jacket not designed for submersion in water and it may ingress over time possibly shorting that communications. Where it enters your home, you should have a surge protector, and at the ground mount I would recommend a low cost switch (and another surge protector to as least try and protect that communications box). Given your running micros you should have a subpanel at the ground mount so it would not be hard to make a code compliant communications cabinet using 120V out there.

                  Other options are RF point to point (PtP). I personally went this route using Ubiquiti LiteBeam AC-23 units. $59 each and you need 2. I get almost 1/2 gigabit and I barely have line of sight over that 400' distance. I have lengthy posts and pics on my blog about this setup.

                  You could also do optical, need a couple of $60 units at each end of the optical cable plus the cost of the premade cable.

                  You could also try powerline units. I tried this over my 400' run but I found the micros had enough noise to make powerline communications very poor. Might work for you for shorter distance, but given you already have conduit, I would not bother with this route.

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                  • #10
                    Thanks for the responses and information. The run to the array is about 90' outside of my garage. If I had to run ethernet all the way to my current router, I'd probably have another 50' or so inside, but would prefer not to, as I'd have to run through all finished space. Can I install a secondary router/device to act as a "wireless bridge" in my garage, and run cat5/6 out from that device? I'm sure the WiFi signal in my garage is strong enough.

                    Thanks tyab, I have filed for a permit and have received approval already from my utility company. Hopefully I don't get in a tricky situation (without having already received the permit), as I've taken advantage of the long weekend and have gotten a good start on things. I happen to be a PE, so providing stamped drawings is not an issue.

                    Here's the structure, at the moment. I still need to finish installing some hardware and bracing. I've decided to use unistrut to mount the panels on, as there are no aluminum suppliers nearby. This turned out to be a much cheaper option and will be very sturdy. I primed and painted the strut, which will hopefully ensure it lasts as long as the panels do.
                    IMG_20170904_170910180_reduced.jpg
                    Attached Files
                    Last edited by brant2000; 09-05-2017, 09:44 AM.

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                    • #11
                      Thats neat. You can save a lot of $ with a treated wood base; there are a few in this area. If you are expecting snow, a gap for
                      it to fall through between upper and lower panels will help a lot. Bruce Roe

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                      • #12
                        I see a lot of shade on them there sticks. Looks nice though. Please update from time to time.

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                        • #13
                          A hint when using uni strut to attach the panels to the PV panel frames. Order some black HDPE .060 thick sheeting from McMaster Carr. Use a utility knife to cut out squares slightly larger then the interface between the unistrut flanges and PV frame. Drill a hole in the center of the square slightly larger than the bolt then cut a slot out to the edge. Make up a pile of them based on the number of connections. Now bolt the panels to the frame but leave the bolts loose until you get everything lined up and square. Now slide the square plastic washers between the frame and unistrut. The bolt hole centers the square in place. Now snug up the bolts. Lot easier and longer lasting then paint. I tried making them without the slot but it adds another degree of freedom in making the initial bolt connection, its a heck of lot easier to add after the fact.The black HDPE is much more UV resistant than the white.

                          I have a 15 year old array that I didnt use washers on and there is some but not a lot of deterioration on the panel frames where the unistrut touches it. I am in rural area away from the ocean. I know of some folks in urban areas and near the ocean that saw corrosion show up in four or five years.

                          On the other hand my 15 year old array is hung off off a wall up against cedar siding and although I spaced it off the siding, one section of the strut touches the cedar and I am seeding corrosion. PT can be very corrosive to galvanized products like unistrut so these slip on washers may also be useful depending on your arrangement.

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                          • #14
                            Originally posted by AzRoute66 View Post
                            I see a lot of shade on them there sticks.
                            Yes, as mentioned I'll certainly experience a degree of shading from time to time. I have been watching the area pretty closely over the past 3 months, and have just started noticing shading on the sides occurring beginning about 5 PM. It's just a rough guess, but I'd expect that shading will only occur on about 25% of the array less than 25% of the time, so think the effect will be <10% of my expected production.

                            Thanks peakbagger, I was thinking about some type of washers. I was actually thinking that maybe I'd use rubber garden hose washers, as they're very inexpensive. That said, I like your suggestion and actually have some left over vinyl flashing that would probably work great. I was thinking it would be a real pain to cut out my own washers, but hadn't considered cutting them into squares. That would be much, much easier than cutting round washers.

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                            • #15
                              Originally posted by brant2000 View Post
                              [...] It's just a rough guess, but I'd expect that shading will only occur on about 25% of the array less than 25% of the time, so think the effect will be <10% of my expected production.
                              I first got interested in solar from the shade analysis perspective. If you have not already tried to quantify it, here is a link that will interest you: http://solardat.uoregon.edu/SunChartProgram.html

                              Enter your configuration and it will printout a solar path chart for the year. Sketch the horizon on the chart and you will know at what time of day, during what months you will experience shading. Generally you will want to do two charts, one for each of the lower two corners of the array. The methods of sighting and transcribing the horizon are many, but such simple tools as a protractor and a compass will suffice in the hands of an engineer. There are also tools out there that can be bought or rented, one of the most popular is the easily google-able 'Solar Pathfinder.' I developed a methodology stitching together a 180+ degree panoramic picture from a leveled tripod, then overlaying a transparent background solar path chart that would probably be overkill for anyone but a hobbyist, but again quite reproducible by an engineer.

                              As you can see, my ridiculously tall chimney gives me issues until 10:00 AM from November through January. That tree to the east will undergo major modification if I ever install a ground array there. Obviously, the view from the western corner of the [proposed] array shows the house and chimney as negligible, while that block wall in the west comes into play during the summer months.
                              Dec30.jpg
                              Last edited by AzRoute66; 09-05-2017, 04:41 PM.

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