My 50kw grid-tie system

[pclausen]

I think I'm finally done adding arrays to my system. I got one array on my shop roof and 5 smaller ground arrays for a total of 205 panels.

Shop roof mounted array consists of 56 265w panels each with a 250w micro-inverter on them arranged into 4 AC strings with 14 panels each.

solar_array1.JPG

Power curve:

shop_roof_power.PNG

2nd array is in front of the shop build and is a "pole-barn" of sorts where I keep my tractor implements. It consist of 45 275w panels. 36 of them are wired in 3 DC strings feeding into a Sunny Boy 7.7k inverter. The remaining 9 panels have micro inveters on them in a single AC string.:

solar_array2.JPG

Power curve from the Sunny Boy section of the above array:

ground_array5_power.PNG
I do have a bit of shading in the morning this time of year.

Next array is ground mounted next to the shop building and consists of 24 265w panels with micro inverters:

solar_array3.JPG

Next array consists of 32 275w panels arranged into 3 DC strings feeding another Sunny Boy 7.7k inverter.

solar_array4.JPG

Power curve:

ground_array4_power.PNG

The final array is separated into 2 sections with 24 280w panels in each. These are all using micro-inverters.

solar_array5.JPG

And yes, I managed to crack the glass on 4 of those panels when I used a stump grinder to trench for the pole barn array.

Power curve:

ground_array2_3_power.PNG

All the micro-inverter AC strings and the AC output from the Sunny Boy's all terminate in a dedicated sub-panel:

solar_subpanel.JPG

I had the power company come out and swap out my 25KVA transformer for a 50KVA one once I got past 25kw capacity.

I'm on net metering with the POCO so anything in excess that I generate builds up a bank of kWh on my account. Unfortunately my household use more than I generate still, but at least the 50kWh of capacity takes a big chunk out of it. Since adding the newest array (the pole barn one), I'm up to about 300 kWh per day, which is pretty good for this time of year.

If I had to do it all over again, I'd go all DC strings and ditch the micro-inverters. But live and learn I suppose.

[solar pete]

Hi pclausen, looks good mate, nice work and thanks for sharing. I would get a few boxes of spare micro inverters ...hehehe....

[pclausen]

You're not kidding about needing spare micro inveters. I have replace close to 40 of them at this point! The vendor sent me about 60 spares after I had a failure rate of close to 20% on the roof mounted array. Those are a real pain to replace as it often involved removing several other panels in order to get to the ones with failed inverters. Things got better for a while and I got tired of staring at the box with over 50 fresh inverters, so that is when I build the 2x24 array, but am now paying the price for not having spares on hand. Right now all inverters are working, and I'd like to think I'm close to being done replacing dead ones as most of the original ones have been replaced at this point. They all fail in the same way. Basically a surface mount cap blows up and takes some other components with it. Root cause is that there was some unwanted stress created when the cap was wave soldered in place during production.

[SunEagle]

That is a really nice pv system. Thanks for sharing the info and good luck with it.

[bcroe]

That is impressive, thanks for the pictures. You are still running single phase, perhaps 400A service
to deal with 200A AC from your system? Are you using the power or selling it? Hopefully you will not
be doing much snow clearing. Bruce Roe

[Mike90250]

It's hard to picture household loads consuming more than 300kwh daily !! wow

[pclausen]

Yes, I have 400A service coming to the main building. From here it goes to a 400A fused disconnect where power is split to the shop building Here's a wiring diagram of the overall setup:

solar wiring diagram.jpg

I dug up some older pics from the construction process. I started the roof array back in November, 2016:

sunmax-11-4-01.JPG

And here's the 1st ground mount during installation which was done at the same time as the shop roof array.

groundmount12-03-02.JPG

And the hillside array which was done in December 2017:

solarpanels_hillside-01.JPG

Shortly after that was done, is when I had the transformer upgraded. It cost me nothing since I was also consuming 20kW 24/7 from my mining operation at the time plus whatever I used in the house hold, so they agreed the transformer needed to be upgraded to prevent the 25KVA unit from being overloaded. My POCO has been really nice to work with throughout the entire process, including getting the net metering arrangement in place. County inspector was also pleased with how I designed and implemented everything.

50kva-02.JPG

Here's a shot of the "power room" that houses the primary meter base, disconnect, transfer switch and backup generator:

kubotainpowerroom-10.JPG

As for why I consume as much as 300 kWh per day, it is because of these guys sitting down in my shop:

miners_7_10_18.JPG

Now that is it getting cold outside, I move some of the rigs up into the house for heat, so that I never have to run my heat pump.

Mining doesn't earn anywhere what it did back in the fall of 2017, but I still manage to clear about $30/day with a power cost close to zero:

AM_11_9_19.PNG

But yeah, if I wasn't consuming 7.5kw 24/7, my solar system would more than cover my energy needs!

[pclausen]

Here's an aggregated plot of power produced yesterday. Had some scattered clouds in the am, but it mostly cleared up by noon:

all_output_11_8_19.PNG

Here are a few pics of the "pole barn" construction. It was far more time consuming to construct compared to the other ground mount arrays that used the Ironridge system with 3" piping.

site_51.JPG

I used 6x6 posts and 2x12's for both the joists and rafters. I then used gold galvanized superstruts (readily available at our local big box store) as the railing onto which the panels were attached. I was originally going to use XR100 Ironridge rails, but the cost was more than double that of the superstruts when taking shipping into account. The superstruts are all bonded together and tied to a grounding rod. The pole barn ground is also extended to the main ground in the shop building.

site_53.JPG

All panels were spaced 1/4" apart and I then used backer rod between panels and sealed with 30 year silicone as I went along. So far it has been completely water tight.

polebarn-100.JPG

I plan to finish it off by adding white steel siding to match the main shop building.

[pclausen]

That is impressive, thanks for the pictures. You are still running single phase, perhaps 400A service
to deal with 200A AC from your system? Are you using the power or selling it? Hopefully you will not
be doing much snow clearing. Bruce Roe

Yes, single phase 400A service still. 3 phase is not an option on my street as it is served by a single 14.4KV line. I'm consuming all the power I produce. If that was not the case, I would build up a bank of kWh on my account to draw from on rainy days.

I'm keeping my fingers crossed that we won't get much snow this winter. We have had as much as 40", but these last few winters I have not been more than maybe 10" at a time. The ground mount arrays are relatively easy to clear, but the shop roof mounted array is a pain in the butt since it starts 14' above the ground.

[bcroe]

That is about optimum, generate your operational energy on site. With lower Micros
output voltage, it looks like a pretty big investment in connecting wire, mostly copper.
Move the hot equipment indoors for winter heat.

Hope to hear a snow report after that season. I consider roof top generation after
snow a write off. After several inches here this fall, I spent some time clearing my
first array construct, but the last one was completely clear. Bruce Roe

[SunEagle]

That is about optimum, generate your operational energy on site. With lower Micros
output voltage, it looks like a pretty big investment in connecting wire, mostly copper.
Move the hot equipment indoors for winter heat.

Hope to hear a snow report after that season. I consider roof top generation after
snow a write off. After several inches here this fall, I spent some time clearing my
first array construct, but the last one was completely clear. Bruce Roe

Based on the latest forecast you might be getting some snow pretty soon.

[hajalie24]

I bet OP is really happy with his life decisions right now lol, hope you didn't sell all the crypto as you mined it.

[pclausen]

Been mining and holding all along. Sold some older GPUs in the fall/winter of 2020 and have been picking up newer ones (RTX 3000 series) as I have been able to snag them.

Since this spring, I have been building up my kWh "bank" with the POCO since my mining rigs are now much more efficient than before.

[bcroe]

What has been your experience with snow? Lately my output in ILL is down 10 or
20% because of the smoke from the west coast. Bruce Roe

[pclausen]

I didn't get a whole lot of snow this past winter. I think I had it twice. One was about 2" and the other maybe 4". I used a broom to drag the snow off the lower 2 or 3 rows on the ground mounted arrays. Didn't bother with the roof mounted panels on the shop since they start at 12' and go up from there.

Overall, this year is looking better than last year so far:

solar2020.PNG

solar2021.PNG

Comparison of output YTD:

20202021.PNG