Anyone mount any Enphase inverters upside-down?

RegGuheert
RegGuheert Solar Expert Posts: 102 ✭✭✭✭
According to page 11 of the Enphase Microinverter Models M190 and M210 Installation and Operations Manual, you can install the microinverter with either side up:

"The microinverter can be mounted with either side facing up to accommodate cable routing."

I have been planning to take advantage of this option in order to try to turn my mechanically-convoluted layout into electrically-organized branches. That is, I was until I received the units today. Looking at them, I see that there is a metal cover that surrounds the metal base. Oriented one way, with the large nervous "e" facing up, it is clear that the unit will shed water efficiently. Oriented the other way and it seems that water could possibly make a home in various places.

Now I realize that these units are fully potted with epoxy resin, but I really don't like to tempt fate if I can avoid it. So I will ask it here: Does anyone *really* install these things upside down? I guess I'm questioning how wise that would be when I am hoping to achieve a 20-plus year life out of most of these things.

Thoughts?

Reg

Comments

  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?

    Reg,

    Wouldn't it be one heck of a wind and rain storm to drive water to the back side of your panels where the inverter sits? Permanent or tiltable? Mine are tiltable and at 55deg elevation right now...everything sheds from front and back.

    Ralph
  • RegGuheert
    RegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?
    Ralph Day wrote: »
    Reg,

    Wouldn't it be one heck of a wind and rain storm to drive water to the back side of your panels where the inverter sits? Permanent or tiltable? Mine are tiltable and at 55deg elevation right now...everything sheds from front and back.

    Ralph
    My array is flush mount on the roof at about 40 degree elevation (10/12 roof). My concern isn't so much about rain getting in there but rather condensation from humidity in the mornings, etc. If any water ever DID seep in there, it would have a tough time getting out. I just feel water is very destructive and I'm not inclined to take the chance.

    I'm still fussing my layout to see if I can put them all rightside-up.
  • RegGuheert
    RegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?
    RegGuheert wrote: »
    Does anyone *really* install these things upside down?
    BTW, I found the answer to my question: Yes! Mr. Radon does! You can see that all the inverters shown in this post are upside-down.
  • anthem
    anthem Registered Users Posts: 8
    Re: Anyone mount any Enphase inverters upside-down?

    They are meant to be installed either way. With the slant on the roof, water will shed if any somehow gets up there underneath the panel.

    If you do reverse them, you will want to reverse the ground wire lug (if not using WEEB-DMC clips) - as screwing a continuous bond wire from the underside wouldn't be much fun.. . .
  • RegGuheert
    RegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?
    anthem wrote: »
    They are meant to be installed either way. With the slant on the roof, water will shed if any somehow gets up there underneath the panel.
    Not all of the water will shed. Here is a picture of one of my inverters:

    attachment.php?attachmentid=1515&stc=1&d=1291763075

    I'm not much of a photographer, so I will explain what is there. That is a toothpick which I placed (I did not push this into the encapsulant) into the open corner of the underside of the inverter. Any water that gets in there will STAY in there. When it freezes, it will wedge the unit apart. Repeat that hundreds of times and the result might not be what is desired. Even if I do end up placing any of these upside down, THIS ONE will be placed rightside-up. (They are not all like this.)
    anthem wrote: »
    If you do reverse them, you will want to reverse the ground wire lug (if not using WEEB-DMC clips) - as screwing a continuous bond wire from the underside wouldn't be much fun.. . .
    Thanks! Yes, I've already started to move some of the ground lugs to the other hole on the other side.
  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?

    I called Enphase about this, same concern I had.
    If you want to avoid this, make note of the cable direction and lay out your inverters carefully. I had to flip some of mine given the layout I planned. I'm not loosing sleep in Seattle over it. Once again, right under the panel. Have yet to see a drop of water on them. I can see the units mounted on top of the garage roof every day I back up, never a drop of water on them.

    Oh, be careful, easy to loose the ground screw/washer. Two people really helps with that task. Funny, the inspector made darn sure those were stainless.
  • RegGuheert
    RegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?
    mr.radon wrote: »
    I called Enphase about this, same concern I had.
    If you want to avoid this, make note of the cable direction and lay out your inverters carefully.
    That's what I plan on doing. I feel it would be best to prevent any possibility of pooling water on the inverters. With a 40" pitch between panels, it is imperative to make two 180-degree bends in the wire anyway, so I might as well mount the inverters the way I want and simply route the wires around the inverters. My only concern is that this requires a 180-degree bend in the short pigtail. Such a bend has a 1" radius (2" diameter). It looks OK doing it in the warm house. Strain seems reasonable. Perhaps I should plan on making those bends warm. We'll see how things go.
    mr.radon wrote: »
    I had to flip some of mine given the layout I planned. I'm not loosing sleep in Seattle over it. Once again, right under the panel. Have yet to see a drop of water on them. I can see the units mounted on top of the garage roof every day I back up, never a drop of water on them.
    My theory is that water WILL get into places where it was not intended. There is nothing to stop humidity from condensing on the inverter and there is no way for anyone to see it, since the top of the inverter is above the bottom edge of the solar panel.
    mr.radon wrote: »
    Oh, be careful, easy to loose the ground screw/washer. Two people really helps with that task. Funny, the inspector made darn sure those were stainless.
    Thanks for the tip! I was hoping that the ground wire could be placed under the lug without removing the screw, but perhaps not.
  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?

    Ground connection tip:
    It was much easier to installed all the Enphase units prior to running the ground wire. So it forces you to connecto to the ground point from the top. I can't see how you could do it from the bottom.
    The washer, clip and screw are easy to loose since the pitch of the roof makes them slide. I didn't loose any, but came close. I had a helper cup their hands under the inverter just in case a part took off (which a few did). Since they are stainless, magnetic tips do not help.

    The inspector looked at all the ground points he could. We only lifted two panels but he did get on his belly to check out as many as possible.

    Be sure the connections to the solar panel reaches the inverters. These leads are short on the inverter, long on the panel. There is one long lead out of the inverter. When I created the plan view of the layout of inverters I didn't take this into account. Also, I had the end that gets capped backwards. (lucky for me this was discovered right away)

    Water:
    The unit is sealed, there might be a gap but it is air tight. I really doubt freeze thaw will effect that gap you pictured. The expansion will be out, there is nothing to allow a parting force to develope. Plus Seattle has little freeze thaw. Unlike lets say Boulder, CO.
    But if you can lay the system out with this side down you'll avoid any concerns.
  • RegGuheert
    RegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?
    mr.radon wrote: »
    Ground connection tip:
    It was much easier to installed all the Enphase units prior to running the ground wire. So it forces you to connecto to the ground point from the top. I can't see how you could do it from the bottom.
    The washer, clip and screw are easy to loose since the pitch of the roof makes them slide. I didn't loose any, but came close. I had a helper cup their hands under the inverter just in case a part took off (which a few did). Since they are stainless, magnetic tips do not help.
    It's likely to be cold on Saturday when I go up on the roof, so my goal is to do as little as possible up there. I'm trying to complete as many tasks as I can in the house before then. As such, I plan to move all of the screws from underneath to the top. I've played around with it a little and it seems that I can leave it loose enough that I can easily slide the wire under the lug and tighten without having to remove the screw again. I'm guessing it won't be quite as simple on the roof with frozen hands and the cold metal.:roll:
    mr.radon wrote: »
    The inspector looked at all the ground points he could. We only lifted two panels but he did get on his belly to check out as many as possible.
    I know our inspector and I'm betting he will not go up on the roof. We'll see!
    mr.radon wrote: »
    Be sure the connections to the solar panel reaches the inverters. These leads are short on the inverter, long on the panel. There is one long lead out of the inverter. When I created the plan view of the layout of inverters I didn't take this into account. Also, I had the end that gets capped backwards. (lucky for me this was discovered right away)
    Thanks for that tip! I've been holding off on finalizing my inverter layout until the panels arrive. For some reason they are taking over twice as long as the inverters to travel across the country. Anyway, there is *almost* enough information on the datasheet to complete the design, but not quite. For instance, it tells the length of the leads, but it does not tell where they start. :roll: Also, there is some sort of structure shown at about the 1/3 and 2/3 points of the panel, but I cannot tell if that will interfere with the inverters. I'm thinking I will need to put the inverters either above the top rail or below the bottom one and turn the panel accordingly to make the leads reach. It sure would be nice to have a photograph of the *back* of the panel, but they only ever seem to want to show the front!
    mr.radon wrote: »
    Water:
    The unit is sealed, there might be a gap but it is air tight. I really doubt freeze thaw will effect that gap you pictured. The expansion will be out, there is nothing to allow a parting force to develope. Plus Seattle has little freeze thaw. Unlike lets say Boulder, CO.
    But if you can lay the system out with this side down you'll avoid any concerns.
    Yeah, I live in Virginia and we have freeze-thaw constantly. While it is easy for Enphase to say mounting upside-down is fine, I will say that 25 years is a VERY long time. There is little testing they can do to determine what water will do to the unit in some unknown climatic conditions. I'll be more comfortable if I mount them so there can be no puddling. I don't think it will be too challenging to find a layout that works, but we'll see how it goes on Saturday.

    Thanks again for all your help!
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?

    "Anyway, there is *almost* enough information on the datasheet to complete the design, but not quite. For instance, it tells the length of the leads, but it does not tell where they start. :roll:"

    from what i'm seeing it does say where it starts as the box is centered on the pv and is dimension g (3.9in or 100mm) away from the end. the leads exit the inner side of the box and that's where dimension g ends by the pictorial. the width of the box is not given or the points within that width that were chosen to exit, but most boxes i don't believe would be larger than 6in and one can guesstimate a worst case placement for them.
  • RegGuheert
    RegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?
    niel wrote: »
    from what i'm seeing it does say where it starts as the box is centered on the pv and is dimension g (3.9in or 100mm) away from the end. the leads exit the inner side of the box and that's where dimension g ends by the pictorial. the width of the box is not given or the points within that width that were chosen to exit, but most boxes i don't believe would be larger than 6in and one can guesstimate a worst case placement for them.
    Thanks, but I'm pretty sure dimension "G" is the distance from the edge of the module to the location of the drilled grounding hole. It doesn't tell about the location of the exit of the leads.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Anyone mount any Enphase inverters upside-down?

    on 2nd look you could possibly be right about that. only way to find out is by either emailing for the info or waiting until you would receive the pvs.
  • anthem
    anthem Registered Users Posts: 8
    Re: Anyone mount any Enphase inverters upside-down?

    I presume you are using rails. So the rails are usually 1/4 in from both sides. Unless the panel is so large that you can't reach back, then you should be fine. They are usually fine lengthwise. If rose goes to worse, you can always reverse the panel and mount the solar panel with the wire on the near rail but you'll have to get rid of a lot of slack. I really like using the weeb cable clips under the panel with the microinverters. THey have a two wire clip now (but I've only used the one). You snap it on each wire and slide the clip on the edge of the panel and it bites in. Great and cheap cable management (and you don't have to wire tie while installing the panels).

    I haven't worried about the water in the inverters while upside down. But yeah, if you push on the bracket, it separates the side seam from the inverter body, not the bracket from the body, so that is a concern, but since the unit is under the panel, I've ignored it.

    You can just loosely screw the grounding lug in and you'll have plenty of run to slide the 6ga copper under the bonding lug. It's not a problem at all. I have started putting loctite silver anti-seize on ALL the ground screws. I have had two of the enphase ground screws seize up while screwing/unscrewing, so I always put loctite when I reverse the screw (and even if I don't) - and preferably indoors. I do try and use loctite silver on all L feet bolts, 7/16" mid/end clamp bolts, etc.. . You just never know when you need to reverse it out and nothing is more annoying than when these seize/strip.

    Also if you need to jump sections on a rail, I prefer the weeb lugs on the rail as well. Since you have a continuos ground wire running, you just run the wire through the lug inline and it works quite well. Better than bonding straps since they have a tendency to get in the way.

    Your difficulty in laying out will be if your inverters are not "aligned". If everything is symmertrical, then its easy to run back and forth. If you run up against a ridge and the panels don't end in the same row/column and you need to interconnect, thats when the run starts and you need to go back/forth between rows (lots of inverter wires straddling rows, etc).

    Just curious - where in Virginia are you installing ?
  • anthem
    anthem Registered Users Posts: 8
    Re: Anyone mount any Enphase inverters upside-down?

    Oh yeah, one other thing - you don't necessarily have to run things complicated. You have a limitation of 13/15 for string to be protected by a 15amp breaker. But you can also run into a junction box attached at the end of the rail and bring the next rails inverters into that junction box as well. You just need another AC interconnection cable for the other string. They actually recommend this method as it reduces the overall voltage drop in the long 14 gauge enphase string. . .

    So, you can have a row of 7 terminated with an AC interconnect at the end of the row. Then another row or 7 terminated with an AC interconnect at the end of the row into the same junction box. As long as you don't exceed the overall limit of the M190/m210, then you're fine. This is a better layout than running 7, and then reversing and running 7 on the way back (14 connected in parallel).