Moving forward on MN solar installation

[sunnybean]

Just an idea for the snow removal, if possible blow it off. I have a Stihl BR600 (biggest blower Stihl makes). They make attachments for blowing your gutters out. I'm hoping that I won't have to scrape my panels. We'll see, I guess.

[pleppik]

Yep. The idea in my head has been to use a long wiper like that with a rubber blade on it and dual chain drives like garage door openers on the ends of it with UHMW poly guides on the ends of the wiper.

For us, 10% more production means that much less generator hours in a year's time. I got enough stuff laying around my shop to build a wiper like that for less than a 100 bucks. The biggest problem is getting motivated to do it. And that motivation usually don't occur until mid-December when I'm chipping ice off panels again.

I wonder if it might be better and/or safer to use something like a long-bristled brush instead of a more rigid wiper blade.

I'm thinking that if there's ice adhering to the panel, the brush bristles will ride over the ice instead of trying to push it off. Since ice is a lot more transparent than snow, just getting the layer of snow off of the ice might be enough to let enough sunlight through to melt off the rest of the ice.

[gregvet]

I wonder if it might be better and/or safer to use something like a long-bristled brush instead of a more rigid wiper blade.

I'm thinking that if there's ice adhering to the panel, the brush bristles will ride over the ice instead of trying to push it off. Since ice is a lot more transparent than snow, just getting the layer of snow off of the ice might be enough to let enough sunlight through to melt off the rest of the ice.

My ground mounted panels can be cleared by using a long telescoping handle with a microfiber covered foam window scrubber. I find this removes snow more effectively than a rubber squeegee window cleaner. You are right - Once I remove the snow, the ice on the panels (even at the bottom edge of the panels) quickly melts in minimal sunlight.

[ChrisOlson]

I wonder if it might be better and/or safer to use something like a long-bristled brush instead of a more rigid wiper blade.

That's what I use to remove snow. But my "brush" is a regular floor broom with the handle stuck inside a piece of 1" PVC conduit and electrical taped so it stays there. My ice scraper is the same thing basically - it's an automotive window scraper with the handle stuck inside a 10' long piece of 1" conduit and taped on. Has worked well here for years.

[pleppik]

We have been given a (tentative) date of June 23rd to begin our installation. So it looks like our number came up.

I'll try to get some pictures, but I have other commitments and won't be able to be around the whole time.

I had a chance to see another recent installation of TenK modules, and those 410W modules are monsters. I'll be interested to see how they get them up onto the roof safely: they're too big to carry up a ladder, and so far nobody has asked about parking a crane in the driveway.

[pleppik]

Just a quick update: we have all the required permits and confirmation for the installation starting 7 AM on Monday the 23rd.

Oddly enough, the only problem we had with permitting is that the city building inspector objected to the fact that we have a couple of bicycles and a canoe hanging from the rafters in the garage. 600+ lbs of solar modules and related gear (plus potentially a couple feet of snow) was not an issue, but a 30-lb Kevlar canoe almost made him deny the permit. Because apparently "it's not engineered for that kind of load." I must have missed the newspaper article about all the collapsing garages caused by suspended bicycles.

So we will be taking down the canoe and bikes before the final inspection.

[ChrisOlson]

Wow. The insanity continues to spread in modern society, huh?

Actually though, that's not surprising. My wife and I are self-insured here. There is no insurance company that we have dealt with that will insure our house, outbuildings or property either for loss or liability. We have had agents come here and when they see that we heat with wood heat, have solar panels, batteries, wind turbines and generators and s&*t - they slam the notebook shut and leave, telling us we are not insurable.

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[pleppik]

Day 1

Today was the first day of the installation--they expect to be done by the end of the day Wednesday.

DSCN0022.jpg
This is the "before" photo. We will have two arrays, each consisting of 8 410W TenK modules. One array will go on the garage roof facing SE, and the other will go on a SW facing section of the roof off the left side of the photo. The SW-facing roof is almost impossible to photograph from the ground because it's three stories above ground level.

DSCN0024.jpg
The installers said they would arrive at 7 AM this morning, and they were ten minutes early (that's the first time that's ever happened to me). The first order of business was unloading the delivery truck with all the materials and taking inventory. In this picture is the stack of PV modules: those 410W modules are monsters, only a little bit smaller than a sheet of plywood. It's a bit of a challenge figuring out how to get them onto the roof safely. Our installer insists on two pairs of hands per module when moving them on the ground, and four pairs at all times when moving them on the roof.

The TenK modules have a lot of the electronics built-in, including MPPT, self-check, and ground fault/load detection. As the installers were unloading and re-stacking each module, they would briefly turn it face up into the light. After a second or two, a little green LED on the module would start blinking, indicating that the module passed its self-test. So we were able to verify that each module was working as it came off the truck. Once the installation is complete, you will be able to verify the status of each module just by watching the blinking lights (different blink patterns indicate different conditions).

DSCN0026.jpg
Finished working for Day 1. All the racking is installed, and tomorrow the real action begins. We're parking our cars outside for a couple days, since the garage has been taken over as a work/staging area.

[Mb190e]

Today was the first day of the installation--they expect to be done by the end of the day Wednesday.

[ATTACH=CONFIG]4391[/ATTACH]
This is the "before" photo. We will have two arrays, each consisting of 8 410W TenK modules. One array will go on the garage roof facing SE, and the other will go on a SW facing section of the roof off the left side of the photo. The SW-facing roof is almost impossible to photograph from the ground because it's three stories above ground level.

[ATTACH=CONFIG]4392[/ATTACH]
The installers said they would arrive at 7 AM this morning, and they were ten minutes early (that's the first time that's ever happened to me). The first order of business was unloading the delivery truck with all the materials and taking inventory. In this picture is the stack of PV modules: those 410W modules are monsters, only a little bit smaller than a sheet of plywood. It's a bit of a challenge figuring out how to get them onto the roof safely. Our installer insists on two pairs of hands per module when moving them on the ground, and four pairs at all times when moving them on the roof.

The TenK modules have a lot of the electronics built-in, including MPPT, self-check, and ground fault/load detection. As the installers were unloading and re-stacking each module, they would briefly turn it face up into the light. After a second or two, a little green LED on the module would start blinking, indicating that the module passed its self-test. So we were able to verify that each module was working as it came off the truck. Once the installation is complete, you will be able to verify the status of each module just by watching the blinking lights (different blink patterns indicate different conditions).

[ATTACH=CONFIG]4393[/ATTACH]
Finished working for Day 1. All the racking is installed, and tomorrow the real action begins. We're parking our cars outside for a couple days, since the garage has been taken over as a work/staging area.

It's a very exciting experience just had ours installed almost 2 months ago.

[pleppik]

Day 2

There wasn't as much progress today as we had hoped due to warm weather (lots of hydration breaks) and a minor snafu with one of the rack rails. It had been cut to the wrong length and will need to be replaced tomorrow.

DSCN0027.jpg
This is our roof at the end of work today. Most of the AC wiring and the inverter buses are in place. The equipment attached to the left end of the center rack row is the inverter bus. There are 7 500W microinverters serving 8 410W modules on a shared DC bus for each of the arrays. Because the modules have built in MPPT, all the modules on the bus can be at a common voltage even if they are outputting different power levels. As the light level increases and the array powers up, the inverters will turn on one at a time to absorb the power. This helps keep the inverters operating near the peak of their efficiency curves even in low light, reduces the duty cycle on each inverter, and provides redundancy in case an inverter fails.

The big grey junction box contains a DC circuit breaker. I was a little concerned that resetting this breaker would require a trip up to the roof and removing a PV module (and remember, these modules are huge). It made me feel a little better when the installer explained that because the electronics in the module are supposed to limit the DC current and shut down when there's a ground fault, if the breaker ever trips it would indicate a major fault which would need to be checked out anyway.

DSCN0031.jpg
This is the roof penetration for the AC connection as viewed from inside the garage. This will terminate at a production meter for the "Made in Minnesota" production credit, but right now the other end of this cable is just dangling.

DSCN0032.jpg
This odd bit of midair conduit carries the AC cable from the SW roof back to the garage where the breaker box and utility meters are located. Routing the cable this way saved several hours of work by the electrician in trying to fish the wiring through inaccessible walls, and it's far enough up from the roof that it shouldn't be bothered by snow or ice in the winter. This is tucked away in a corner of our roof which is only visible from one particular spot on our back deck, so we can live with how it looks.

Our installers still expect to be basically done by the end of the day tomorrow, though there will still be some cleanup details, inspections, and installation of the meter to take care of over the next couple weeks.

[Rdjntx]

Nice looking install. I am surprised that mid-air conduit will pass inspection LOL! you will no doubt be happy with it. getting your first zero balance bill (or a bill that is a third of what you are used to) is awesome.

do you plan to install an internet monitoring device like egauge or TED ?


My install in Texas has been up and running for 2 years next month. I don't think I paid a dime for electric in the last year. I toss a few bucks at my account and hadn't checked it for a few months. checked it yesterday and had a 300+ dollar credit.

[pleppik]

Nice looking install. I am surprised that mid-air conduit will pass inspection LOL!

The electrician suggested it. I'm going to assume he knows what he's doing.

It's unorthodox for sure, but on the other hand, the unsupported run is not that different from what it would be if it was clamped to the side of a building, and it will never be submerged in water, buried in ice, or otherwise structurally abused.

do you plan to install an internet monitoring device like egauge or TED ?

We're getting an eGauge, and we will be monitoring the output of each array separately along with our consumption. That's going to be extremely interesting data.

[pleppik]

Day 3

We had good weather for working on the roof today: cool and overcast but no rain. The installers put in a heroic 13-hour day and got the project wrapped up (mostly).

IMG_0632.jpg
Here are the first modules getting lifted onto the roof. This was the first residential installation this company has done of the 410W panels (and, I am told, only the third residential rooftop installation of these modules anywhere--these have been mostly marketed for flat roof or ground mounted systems until now). If it looks like they are trying to figure out the best way to get them on the roof, that's about right. These are at about the limit of what you can move around on a roof by hand, and the installer told me that for future installations they're going to consider renting a lift or crane for a day.

DSCN0033.jpg
The completed installation over the garage. An identical array sits on the upper-level roof off the left side of the photo, but can't be easily seen from the ground. 6.56KW total in 16 modules.

Of course the advantage of these huge modules is that once you horse them into place, there's fewer bolts to tighten, fewer cables to connect, etc. With 250W modules there would have been 26 modules to get the same capacity, and correspondingly more stuff to fuss with to complete the installation.

DSCN0034.jpg
Our wall of meters, with a blank place for the production meter which the power company will supply when we complete the final inspection. The two existing meters are for our the home and for the geothermal HVAC (which is metered separately because it gets a special rate). The power company also gets a special disconnect switch they can use to completely isolate our solar panels from the grid for safety. Even though the solar inverters are supposed to stop producing power if the grid ever goes down, the power company is understandably paranoid about keeping their linemen safe.

DSCN0036.jpg
And a third set of breakers which disconnect the solar production. All told there are three ways the system can be shut down: automatically if there's a blackout, using these breakers, and with the power company disconnect. Definitely some belt-and-suspenders going on here.

There are some minor cleanup details left to be done, and we have to pass three separate inspections (in sequence!) before we can start producing power: an electrical inspection, a building inspection, and a power company inspection. I'm told that the power company is the longest wait, and they won't even schedule it until the other two inspections are done. It's likely to be a few weeks before we're fully activated.

[HX_Guy]

Those are some HUGE panels!