Residential solar people?

[larboc]

I'm pulling the trigger on a solar installation on the roof of my home this summer and looking for any input. I've got enough space (38x20 4:12 architectural shingle roof) on the west-southwest facing portion of my roof to put the 6 system that I'm planning on needing. I was surprised that it's not that much of a penalty in output to have the panels put on a roof that's not directly south facing, only 5% or so so I'll just add another panel or two to make up for it. I don't have a good place on my property to do ground mounted that wouldn't be shaded so that's out.
Right now I'm looking at using Iron Ridge xr1000 racking because that's what I've got experience using already and it seems nice and reasonably priced. I'd go ahead and get their wire management stuff too.

Planning on 18x 325W Trinas 3 up landscape with the panels starting at the bottom to help snow dump off. I'd like to go with frameless panels but I don't see many options that aren't bi-facial (more expensive and won't do anything when roof mounted)

No idea what inverter, likely the SMA that allows 2000watts of backup power during a grid outage.

My power company gives 1:1 net metering for a year and I rarely have a power outage so I have no interest in adding a battery at this time.

Thoughts?

 

[[486]]

there's a guy in carlton mn that's selling 300w panels on craigslist for like $125 apiece iirc

might be worth the drive to save some money

 

[Sceep]

F Ironridge. Unirac or nothing!

They make "ok" stuff and have been one of my biggest competitors for ever it seems.
We cannot figure out how they get their tool-less splices through UL for bonding cert. It just doesn't work in our lab, or anyone elses. They have UL on the payroll.
The UFO clamps are ugly and dont have enough surface area under the head of it to be approved by some module manufacturers.

Trinas are good modules. Forget about frameless, they suck to rack.

 

[larboc]

F Ironridge. Unirac or nothing!

They make "ok" stuff and have been one of my biggest competitors for ever it seems.
We cannot figure out how they get their tool-less splices through UL for bonding cert. It just doesn't work in our lab, or anyone elses. They have UL on the payroll.
The UFO clamps are ugly and dont have enough surface area under the head of it to be approved by some module manufacturers.

Trinas are good modules. Forget about frameless, they suck to rack.

Looking at frameless only for their snow shedding abilities. I put up 18 stion frameless panels this winter, wasn't all that bad since they were smaller panels. Used iron ridge frameless clips on ground mounted racking though. I see what you man about clamping area. It's pretty much just the edge of a washer holding them down. I thought that the splices had to have a jumper self tappered across it?
I'll look into Unirac, I have no brand loyalty here, I've just only used ironridge for roof mounted racking.

 

[RPS1030]

Looking at frameless only for their snow shedding abilities. I put up 18 stion frameless panels this winter, wasn't all that bad since they were smaller panels. Used iron ridge frameless clips on ground mounted racking though. I see what you man about clamping area. It's pretty much just the edge of a washer holding them down. I thought that the splices had to have a jumper self tappered across it?
I'll look into Unirac, I have no brand loyalty here, I've just only used ironridge for roof mounted racking.

Just plan on zero for the winter and be happy to get any production. Actually being on the roof of a heater structure can help with the melt some.

I’ve got ground mount sites across the state to your west. The fixed arrays with framed modules do ok for most of the winter, but we end up with a few that are almost zero for 3-4 week stretches. The super cold screws us more than the actual snow. Once some moisture gets a hard freeze over the modules, production and heat goes away and it does nothing until it warms up.

Our latest batch of sites are Single Axis Trackers with Frameless Modules. So now we can’t confirm if the tracking or the frameless sheds snow better . And yeah, handling them sucks, supposed to go straight from the pallet to the install. Set them down in between equals microfractures.

 

[larboc]

Just plan on zero for the winter and be happy to get any production. Actually being on the roof of a heater structure can help with the melt some.

I’ve got ground mount sites across the state to your west. The fixed arrays with framed modules do ok for most of the winter, but we end up with a few that are almost zero for 3-4 week stretches. The super cold screws us more than the actual snow. Once some moisture gets a hard freeze over the modules, production and heat goes away and it does nothing until it warms up.

Our latest batch of sites are Single Axis Trackers with Frameless Modules. So now we can’t confirm if the tracking or the frameless sheds snow better . And yeah, handling them sucks, supposed to go straight from the pallet to the install. Set them down in between equals microfractures.

I've got ground mounted framed and frameless panels right next to each other on the same racking and the frameless do shed somewhat better than the framed for the few snows they were installed in time for. Will have a really good data set after next winter from them (DC I/V for each string, photoderived snow cover, in plane pyranometer, albedo data, etc. Identical panels other than the frames. We get such short days and so much cloud cover from the lake that I don't expect there is enough power difference no matter what we do to make a difference worth any hardware cost increase in december/january/february but we'll see.

 

[bigun]

Been thinking about going ground mount system house sits on a south facing hill that would be great. I would love to be able to store my own power, but with an all electric house

 

[ZeroFux]

Not sure how you can connect a inverter without a battery bank, and if you can’t get southern exposure it might not pay for it self like is supposed to. I’ve been completely off grid for 20 years, but not real familiar with grid tie.

 

[tsm1mt]

I put in ~6KW two years ago on the old garage. 245w used Trina panels, 12 panels east facing, 12 west.

Last summer I built a new shop, and installed 30 400w Jinko units per side.

Both roofs are 5:12 pitch, and the panels face roughly east and west (not south).

I, too, ran the numbers over and over before finally putting the new shop roof with east/west faces just like the old shop.

I found covering the e&w made more power than covering a n&s, though if I could only do one face, the south won.

The old shop has ~3kw east and west, feeding into an SMA 7.7 inverter, with one MPPT input unused - the plan is to add another string on the lean-to at some point.

The new shop has two of the SMA 7.7 units.

I'm feeding 12kw into a 7.7kw inverter, but thanks to the east/west orientation, it doesn't clip output too much.

I have three strings going into each inverter - 10 East panels, with 2x10 West, and 2x10 east with 1x10 West.

I debated over and over on adding a third inverter, but decided I had to cut costs somewhere.

Ideally, I'd add a third inverter, so it would be 10east/10west, and then I'd add just a few panels on the south facing wall, vertically, maybe 5-6 panels each - that would give me more winter output, but also just "top off" the 8kw of input.

As it stands, being May right now, I have some clipping.

On 5/6 we had a sunny day.

From about 10am to 2pm my output was limited - there were spots where it dropped below peak, but my curve has the top clipped. My other array, with the two strings facing west, from 1pm to 3:30

Consider that my 6kw array peaked at only 4kw output that day - still a pretty flat top to the curve - and evenly distrubuted east/west panels - but on good days (and May is supposed to be one of my peak production periods) I'm peaking at 66% of the array, so my 12kw array should be doing 9kw but I'm capped at just under 8.

Anyhow..

I used S-5! brackets on both buildings. a Z shaped plate VB-47 stand off, then the PV mounts that clamp the frame of the panel.

On the new building, I paid attention to the Jinko specs that called for having the panel stood off the roof for fire ratings, so there's a 4x2 aluminum spacer / stand off in between.

I skipped the Iron Ridge and everything else with all of the expensive racking.


Back to the inverters - the first install was under NEC 2014 and so I have a single rapid shutdown box. The Secure Power Socket works great - I used it when the transformed was replaced when we upgraded to 400A service. The east/west arrays really flatten the curve so I can get my 2kw output most of the day (8:45 to 6pm on 5/6) - I ran an extension cord into the house and kept the computer on and working.

Note that the NEW inverters, and the NEC 2017 required module-back mounted rapid shutdown boxes DOESN'T WORK.

The inverter sends the Rapid Shutdown "turn on" signal - but when the AC is cut, it stops doing that.

The solution, which I still need to test, was to install the TIgo RSS sending unit as well - it runs on 12VDC, so when the power goes out, I'll hook a battery up to turn the rapid shutdown back on, then I should be able to use my SPS.

This time, I wired the SPS into the shop as well as outside, so we can be indoors using power..

One big advantage of the SMA string setup - I don't notice a big increase in RFI - something my other ham friends complain about. That was one specific reason I picked the SMA.


I did most of the work myself - I'm not a sparky, but I pretend to be one.

I did almost all of the 6kw install, just hiring a master electrician to add the knife-switch and a few things since I needed one to sign off for the net metering anyways.

I hired the same guy again for this job - where his guys replaced the main panel on the house, did the roof penetration for the conduit down to the inverters, and some of the wiring in there.

I hired some laborers with a man lift to help me put the 72cell panels on the 16' high roof - I did the 60-cell panels on the old garage mostly by myself, occasionally with my 11 year old helping.

I did end up adding conduit along the roof peak here and ran the PV wire inside.

I was able to use the panel pigtails to "S" may way across so that + is on the "top/north" end, and "-" is on the second-down/south end (or something like that)

So my strings are 10 panels, 5 across, two high. Then the same, but rows 3-4, and rows 5-6.

I configured it so I have "East, 3-4" with "West, 1-2, 5-6" and "East 1-2,5-6" with "West 3-4"

I was trying to minimize the impact of snow (not) melting, and by doing the east/west bit, peak production drops compared to "all east" but overall production doesn't - thus, two 7.7KW inverters being fed by 24kw of panels.

The 400w panels were running $200 each last year.

Other things to note - you'll see a 200A panel mounted to the outside of the shop.

The only thing in that panel are the two 40A solar breakers. Feed-thru lugs power the interior 200A panel, with a 200A main breaker.

The 20% rule wasn't going to work for me, so I had to make sure I protected everything so I couldn't draw more than 200A through a panel - the 200A breaker at the service entrance protects the wire to the shop. The 200A breaker inside the shop means the shop panel can only see 200A across it.

Combined, it means I won't see 280A across the exterior panel by drawing 200A from the power company and adding 80A of Solar, because the draw can only be 200A into the interior panel.

Otherwise, I was limited to a single 40A breaker (like the first install).

That was also why I had to upgrade to a 400A service - that, and I put an electric boiler in the shop for the radiant heat..

Also note, I purposefully put the panels on the old shop to the north side of the roof - anticipating I would build the shop and it would shade it.

I successfully avoided shading, even in winter.

Even here in Montana, the two 12kw setups made 200kwh each (400kwh total) in December.
January was 364 & 400.
Then ~550, ~1200, ~1500 each in Feb/March/April.

Ignoring the shop heat, I'm gross overkill on power production right now - but the shop heat will eat into that, and I was anticipating putting a strip heater in the house furnace, and contemplating adding an electric car to the fleet ( to go with the electric tractor I built)

 

[larboc]

Not sure how you can connect a inverter without a battery bank, and if you can’t get southern exposure it might not pay for it self like is supposed to. I’ve been completely off grid for 20 years, but not real familiar with grid tie.

Lot's of grid-tie inverters exist that don't use a battery, probably the most common type of solar inverter.
A perfectly south facing roof is best but not as crucial as you'd think. The NREL site has an easy calculator for figuring out how much of an affect it makes. The 45 degree twist toward the west my roof has doesn't knock it down that much. 5% or so less performance vs. perfectly south. Panels are cheap enough that I'll just add a couple more to make up for it.

 

[ZeroFux]

Lot's of grid-tie inverters exist that don't use a battery, probably the most common type of solar inverter.
A perfectly south facing roof is best but not as crucial as you'd think. The NREL site has an easy calculator for figuring out how much of an affect it makes. The 45 degree twist toward the west my roof has doesn't knock it down that much. 5% or so less performance vs. perfectly south. Panels are cheap enough that I'll just add a couple more to make up for it.

Thanks for the info. The technology has grown by leaps and bounds in the last few years. My panels are still mounted to a 16ft horse panel. Lol

 

[tsm1mt]

Lot's of grid-tie inverters exist that don't use a battery, probably the most common type of solar inverter.
A perfectly south facing roof is best but not as crucial as you'd think. The NREL site has an easy calculator for figuring out how much of an affect it makes. The 45 degree twist toward the west my roof has doesn't knock it down that much. 5% or so less performance vs. perfectly south. Panels are cheap enough that I'll just add a couple more to make up for it.

SMA Secure Power Supply gives me a 2kw outlet without the cost and maintenance of batteries.

Add a UPS for fun. :)

I used PVWatts to work out the impacts.

I also downloaded the day by day, hour by hour estimates and merged my east and west arrays to see what the overlap was to be to estimate my "losses" by under-sizing my inverter.

 

[kf4zht]

I used S-5! brackets on both buildings. a Z shaped plate VB-47 stand off, then the PV mounts that clamp the frame of the panel.

How did you like their brackets? Thats what I am looking at to cover my back roof, which is exposed fastener metal.

Considering just going with a hybrid inverter and just put plugs near the devices I want to power. Only trying to offload the stuff that is always on and could use backup anyway

 

[tsm1mt]

How did you like their brackets? Thats what I am looking at to cover my back roof, which is exposed fastener metal.

Considering just going with a hybrid inverter and just put plugs near the devices I want to power. Only trying to offload the stuff that is always on and could use backup anyway

I liked them enough to buy them twice - once for the first, then again for the second.

Standing seam roofs would be cooler with their special brackets, but I just have the VB-47 drilled through my exposed fastener steel roof into the trusses on the old building, and into the purlins on the new one.

On the old building, the pain was shimming the trusses after the fact - sliding 1x into the gap between the purlins, hanging over the blown insulation and leaning all the way down to get it into the eaves basically..

So when the new shop went up, I had extra purlins installed 20" on center along with the standard 24" (the plan was ONLY 20" centers, but the crew was so used to 24", we wound up adding the extras after the fact)

I ran the numbers a lot of times, and this was cheaper by a good margin over the various racking systems.

At least, assuming my time is free - maybe if I were paying people to mount them, a few more dollars on the racking to speed up install would make the difference.

The challenge with the S5 on my roofs is getting the mount to line up with the support - thus the extra purlins, but still some work to line them out correctly.

Plan on getting a couple extra PV kits, in case you cross-thread one. That seems to only happen after you have to remove a panel from the field beause you got the back wiring wrong or something, which only happens once or twice. :)

The big thing for me on the second install was reading that the panels wanted 4-5" of air-flow, and the S-5 setup puts it right off the roof, thus I fabricated the stand-offs.

Using the VB-47s (and then my stand-offs) you can take a burr and add to the slot to fix small boo-boos on mount spacing.

I found the best overall deal on the hardare from Rapid Materials though I also found some VB-47s on Ebay once, too.

If I wanted backup power, I'd probably do more UPS, or maybe a PowerWall setup.. the power is fairly regular here, so the SPS is not high on my priority list, but a cool thing to add and have.

Really, when the power is out, it's night time power that I need to keep the gas furnace going, and the SPS isn't going to do that.

But the SPS could run a battery charger, and a small bank of batteries which I could make up if/when needed.

I have enough vehicles.. :P

 

[junkytj]

blah blah really neat solar stuff

blah blah ( to go with the electric tractor I built)

Build thread? Action videos?

 

[ThePanzerFuhrer]

I have been thinking about starting to put up a array at the pit. My electric bill is 6-900 a month. I have the perfect south face that has zero obstacles would be perfect for these.

What do I have to do to be legit? Call up the power company and get their blessing? I’m not gonna hire someone this would be a fun project to do with the kids. I would build what ever structure the panels would need to mount to. I could even make the fuckers pivot with some linear actuators. Wouldn’t be too much to make. That way I could make them shed the snow in the winter lol.

I need a real world education please!!

 

[[486]]

my power company says that you set up the panels and inverter, they'll wire up their second meter and then they pay full metered rate for up to 40kw
if there are overruns they'll cut me a check instead of just building up a credit on the account

you should call and ask them about it tomorrow, and make sure to ask if there's a difference if you set it up as being attached to the business, or as being attached to your house
the federal tax credit might only apply to individuals or something

 

[SomeGuyFromOlympia]

What kind of time frame does it take to break even on something like this project?

 

[[486]]

What kind of time frame does it take to break even on something like this project?

depends mostly on how much the power company pays you for power
where I'm at now it's full metered rate of 13 cents kw/hr, down in the cities it was 2 cents per kw/hr
system cost factors in there too, but you can figure on a few thousand dollars for a modest size setup, pretty much the sort of money anyone can throw away on shit they find neat

if your power company is paying something stupid low, no need to even waste a second thought on solar

 

[tsm1mt]

Build thread? Action videos?

Back on PBB - 5 years ago, and still going strong. Sold my gas tractor.

I've thought about adding a second 2kwh battery but haven't.

Works great for plowing snow in the winter - starts every time, hasn't frozen up. :)

I can plow several times before charging, but the spinning blades of death really draw the power.

 

[tsm1mt]

What kind of time frame does it take to break even on something like this project?

My two systems were 6 and 7 years when I did the math.

30% or 26% federal rebate, Montana gives me $1000. at ~$.10/kwh about 6 or 7 years.

First system was used panels to get it to 6 years. Second system was supposed to be 6 years, but it took 3 days to install the panels instead of 1, and those two days added a year to my cost recovery.


As to how-to - most places you need the power company's blessing, and to get that you need to pull a permit, and here we need a Master Electrician on the permit.

Then it's a question of whether you need a building permit for your mounts and all of that.

Ground mount has some lower "rapid shutdown" requirements - primarily there for the fire fighters on your roof.

Here in Montana, it turns out that a 1kw system saves you $100 a year on your power bill.

That'd be a start to figure out if it's worth it.

 

[WTF?]

What kind of time frame does it take to break even on something like this project?

Math on my 11kw system with no batteries worked out to breakeven around 10 yrs at 10.5c/ kW. ( with 1:1 net-metering)

now Mine was contractor installed a yr ago, but due to the ‘rona scare, I paid about what I could buy the hardware for, for the installed system.

 

[u2slow]

depends mostly on how much the power company pays you for power
where I'm at now it's full metered rate of 13 cents kw/hr, down in the cities it was 2 cents per kw/hr
system cost factors in there too, but you can figure on a few thousand dollars for a modest size setup, pretty much the sort of money anyone can throw away on shit they find neat

if your power company is paying something stupid low, no need to even waste a second thought on solar

I could be wrong, but I don't think solar can pay for itself in the pacific northwet.

My utility has successfully moved the regulatory goalposts to impinge the profitability. Its a credit against your consumption. If by chance you're a net producer over the course of a year, they pay you 'market rate' for the excess. Market rate is their bulk market, not our consumer market.

 

[WTF?]

i installed my array facing west/southwest due to layout preference/ roof design, and similar to OP, the PVwatts calculator said the difference between due south facing was very minor as well.

Yr 1 actual performance has exceeded the calculator estimates so I’m pleased.

I’d suggest selecting an inverter on performance first with monitoring interface/ capability a close second.

the solar edge inverter monitoring software & data output is okay, but not great. i chose to supplement it with another power usage monitor tool to get the data I wanted and double check my net metering functionality/ accuracy.

 

[tsm1mt]

I could be wrong, but I don't think solar can pay for itself in the pacific northwet.

My utility has successfully moved the regulatory goalposts to impinge the profitability. Its a credit against your consumption. If by chance you're a net producer over the course of a year, they pay you 'market rate' for the excess. Market rate is their bulk market, not our consumer market.

Sounds like you have it good in the PNW.

Here, we get a 1:1 credit, but at the end of the year, if you're a net producer, you get ZERO.

My first 6kw array was set up to cover 50% of my power usage, to make sure I didn't overproduce.

Now I'm at 30kw, which should more than do it - but I used 2500kwh in February heating the new shop, before I'd produced enough from the new array and so forth - we'll see how this year goes.

Shop might be 70-deg to burn up the excess power.

(Assuming I don't get the strip heater added to the house furnace to divert some of the excess electricity to keeping the house warm..)

 

[u2slow]

Sounds like you have it good in the PNW.

Here, we get a 1:1 credit, but at the end of the year, if you're a net producer, you get ZERO.

Haha... builds on my theory that we can't net-produce easily up here. I should have just googled the PV maps. I'm right above the darkest green area on the top left.


The grandfathered rate thru 2024 was 9.99 cents/kWh for annual excess, existing installs. No idea what the new reduced 'market rate' is.

 

[larboc]

F Ironridge. Unirac or nothing!

They make "ok" stuff and have been one of my biggest competitors for ever it seems.
We cannot figure out how they get their tool-less splices through UL for bonding cert. It just doesn't work in our lab, or anyone elses. They have UL on the payroll.
The UFO clamps are ugly and dont have enough surface area under the head of it to be approved by some module manufacturers.

Trinas are good modules. Forget about frameless, they suck to rack.

So where do I go for the best deal on Unirac?

 

[Sceep]

So where do I go for the best deal on Unirac?

We only sell through distributors and I don't have access to salesforce to see who has the best discounts.

You can locate your nearest distributor here: Unirac Solar PV Racking - Local Distributors I'll reach out to a few guys and see if i can find out whos got a decent discount up there.

 

[mobil1syn]

tsm1mt what does the math say about ROI? around here i am looking at 10-15yrs at my current rates/consumption.

 

[bigun]

We only sell through distributors and I don't have access to salesforce to see who has the best discounts.

You can locate your nearest distributor here: Unirac Solar PV Racking - Local Distributors I'll reach out to a few guys and see if i can find out whos got a decent discount up there.

LOL Your company shows me every distributer in the US when I put in my zip code