Newbie here doing a 20.8kW DYI install (80 sunMAX 260W panels with microinverters)

[pclausen]

Haha, I was thinking the same thing when I uploaded that pic with the stumps showing. Don't worry, I have a stump grinder for the tractor, they will be gone soon.

Here are some pics of the (almost) completed install. (sorry to those on metered data rates, I like to post pics!)







I ended up using 3/4" PVC conduit and then reducers down to 1/2" for the last bit to the end run connectors of each string. That 1/2" conduit coming up the pole is for the cat 5e cable.



Here's the 23' run from the array to the shop.



I wrapped the 3/4" conduit for the strings around the corner of the shop building.



Since the meter base at the shop is really just a junction box for the shop sub-panel, I figured I'd save myself some time and just feed the wires from the ground based arrays through it to the sub-panel on the other side. If the inspector has an issue with it, I can easily drill a hole for a separate conduit, or bypass the "meter base" completely. I will leave plenty of slack wire in the sub-panel, should that end up being the case.



A couple of shots showing all 80 panels in all their glory.





All that is left to do is to screw down the wires to the end run connectors, and connect the wires to the 2 20A breakers inside the panel. Also need to pull the cat5e cable for the solar gateway. I hate how it gets dark so early this time of year (so my my panels)

[bcroe]

That installation may outlast a couple generations of the electronic parts. But get rid of those tree stumps. I try to get mine underground
and grassed over right away, before any tree huggers see them. Bruce Roe

[Mike90250]

Looks like a great install. do you do contract work & travel ? And it helps to have the machines to do the work.

[DanS26]

All I can say is that array is well grounded......in more ways than one. Thanks for taking the time to post pics of your progress.

[pclausen]

That is probably true, although the Sense is a new entry into the market that samples at several million times per second. Once the distinct signature of each device has been identified, you can then manually turn on each of those devices one by one, see which of the devices marked unknown starts to use power, and then label it accordingly.

Make good progress yesterday. Got the panels out to the front of the array after completing the grounding.



1st row went on real easy. 2nd row was little more work since I had to raise each panel up from "inside" the ground mount. 3rd row was more of a pain, since I had to use a step ladder to raise each panel up high enough to clear the rails and then lay them down. No way the step ladder would have worked for the 4th row, so I resorted to using the loader for that row. Guess I had gotten spoiled from doing the roof array first, since all I had to do was drop each panel down into position.



Got 3 of them done before dark. Getting ready to get the last 3 done this morning, then do my wiring and bring them online!

[DanS26]

Just be aware that those devices have a hard time to identify variable speed devices like blower motors, hair dryers, water heaters, etc.

[pclausen]

Well good news. The POCO has agreed to draw up a letter stating that they are ok with me having my inverters programmed to operate at a voltage higher than 253.5V. I figured that if my average voltage from the POCO is 250V, adding 10% for a max of 275V should cover any scenario. The inverters probably have an engineering upper limit, but I'm sure the vendor will know and know program above whatever that is.

In other news, I got the rails all installed today and will start mounting the panels to them tomorrow. After calculating the distances between the rails, I ran a tape measure across both cross pipe and marked with blue electrical tape where the bracket edges should be. I then figured out how far in from the edge of the rails the brackets should be, and pre-mounted them.



I also got my sense monitor today. Here it is installed in the disconnect switch. One set of CTs are on the load going to the house, the other set of CTs are on the feed coming from the shop. I do have a few devices that are always on in the shop, like a 10 port switch, a WiFi access point, and the solar gateway. Between them, they consume maybe 30W, so no big deal. The sense might actually be able to adjust that out of the total it shows me.



Technically you are supposed to power it from a 240V breaker, but that would have been a pain. So I just crimped on some connectors and slipped them under 3 mountings screws to pick up L1, L2 and Neutral. I'll add some small in-line fuses when I get a chance.

So here's what the Sense App looks like on in iPhone. Here's the default view:



And the view showing the power consumption over time. It is very sensitive to anything in the home being turned on and off as can be seen



Zoomed out view since I installed it this afternoon:




It will take it a few days to identify all my devices and there will of course be some that I won't be able to ID. But I'll work with the sense team to tell them what they are. For example, I suspect it will have a hard time with my various UPS'es and Laser Printers. On the other hand, it should easily be able to identify stuff like microwaves, fridges, washer, dryers, garage door openers, HVAC, etc, as those all the recognizable power signatures.

For someone doing Solar, this looks to be a really nifty device. Those couple of screenshots are just the tip of the iceberg. Once they get the web app online, and give me direct access to all my power data in the cloud, I should be able to gain great insight into the power all my devices consume.

[bcroe]

A "frequency shift" may be no more than a delayed rising edge or a spurious voltage spike.
And a large motor being turned on and off could affect the waveform enough that I believe the inverters could interpret it as a frequency shift.

None of the inverters allow you (the installer or owner) to program it.
I think all the major manufacturers allow you to upload new programming from the manufacturer.
I wouldn't expect that situation to change - otherwise they risk being sued for an idiot reprogramming the inverter to do 480V in the US.

Yes the inverters made possible by recent (to me) technological advances are quite sensitive, and subject to rules and software
that hasn't caught up with the real world yet. If the PoCos insist on 125/250V set points plus tolerance, then rules need to match,
plus considering the voltage RISE (not the DROP we are so used to thinking about) for this app. I would not advocate or expect
to encounter a 240VAC inverter capable of 480VAC output, but it should have at least a HIGH LINE sort of operating option. Keep
in mind, a residential scale PV system CANNOT set the line voltage, and it can't operate without the line.

Yea the edge of a 60HZ sine could get beat up by a motor or SCR control or other heavy load, but I'd be inclined to call that a
phase change. They still occur at the SAME RATE (frequency) or period as set by the rotating machinery at the nuke plant down
the road. Bruce Roe

[foo1bar]

You are never going to cause a frequency shift. Hope "they" reprogram the inverters; its a lot better to do it yourself. Having your
big new investment shut down is not good. Maybe a consideration of any inverter purchase should be if you can program it.
Bruce Roe

A "frequency shift" may be no more than a delayed rising edge or a spurious voltage spike.
And a large motor being turned on and off could affect the waveform enough that I believe the inverters could interpret it as a frequency shift.

None of the inverters allow you (the installer or owner) to program it.
I think all the major manufacturers allow you to upload new programming from the manufacturer.
I wouldn't expect that situation to change - otherwise they risk being sued for an idiot reprogramming the inverter to do 480V in the US.

[bcroe]

You are never going to cause a frequency shift. Hope "they" reprogram the inverters; its a lot better to do it yourself. Having your
big new investment shut down is not good. Maybe a consideration of any inverter purchase should be if you can program it.
Bruce Roe

[pclausen]

I'll try that over the weekend or maybe tomorrow.

One of the ubnt engineers told me this about the inverters:

--- cut ---
The inverters will connect after monitoring the AC line for 5 minutes, IF everything is within the right ranges (59.32 to 60.48 Hz, 220.5 to 253.5V). There is actually a tighter requirement on reconnection vs tripping so that there's some hysteresis if there are true grid problems.
--- cut ---

So if the compressor did trigger the inverters going offline, the likely reason they did not come back on within 5 minutes (it took hours), was that the voltage was above the tighter requirement for re-connection after an "AC Event".

I'll try to map the mac addresses of the inverters that went offline, to the string(s) those panels were on. I should have taken a snapshot of the cloud management console that showed the assigned panel locations that were out. Might just wait for the next event and do that to make less work on myself.

[Mike90250]

I do have a 7.5hp compressor in the shop that will cut on once or twice a day to maintain pressure. Could that be enough to trigger an AC frequency event?.....

Easiest is to trigger it manually and see if the inverters drop offline. But a Frequency glitch, they should recover and be back online in 5 minutes.

[pclausen]

I do have a 7.5hp compressor in the shop that will cut on once or twice a day to maintain pressure. Could that be enough to trigger an AC frequency event?

The sense power monitor that I'm getting does more than 1 million samples a second (main reason is to detect the unique power signature of my individual loads throughout the house and track them all individually) but my hope is that I can also study that data to look for abnormalities on the line side, not just the load side.

[SunEagle]

Turn on a few giant resistive heaters to warm up the shop and see if that reduces the voltage enough that they can come back online.
(or if you don't have heaters, but have a number of halogen lights, a bunch of those would have similar effect (and add some heat to the shop too).

I think FNG AZ has a point. The screen does list an AC Over Frequency fault. Not sure if that is a reason for the inverter disconnecting or an after affect of the disconnect.

The one issue I always had was that those inverter monitors would provide the information but were way too slow to show exactly when it happened, while the software would be sensing the grid power parameters and acting down in the "10 cycle" range which is pretty fast.

[pclausen]

I got 12 250W metal halide lights in the ceiling as well as a pair of 500W halogens for when I need light "right now" before the MH units get up to speed. That will at least give me a 4000w load. 4 of the 6 inverters have come back online again already on their own. I'm not at home today, so I'll try that trick over the weekend it if happens again.