What do you wish you knew about solar before making the decision

[peakbagger]

I have designed and installed 3 arrays over the years plus did a major upgrade on one of the three. The things I can comment on are things about the installations

The biggest thing to keep in mind is that PV systems are generally permanent additions to a house. They all look pretty when new but every component needs to be something that will last 20 plus years at a minimum. The installers don't typically have the same time horizon that the property owner should have.

Plastic zip ties even if they are supposedly UV rated still have a finite life in the sun. Not generally an issue in the shade but I really need to switch to SS zip ties. I would not allow an installer to use plastic zip ties except possibly indoors.

Spend the money and run homerun wiring inside a metal conduit through the house. Conduit on the outside of the house looks like cr*p in the long run. If in doubt go with the next size conduit, the NEC fill tables are decidedly the minimum size conduit that wires can pass through but it will require lots of cable lube and pushing and pulling. The material cost to upsize is minimal.

Use stainless steel fasteners, no carbon or zinc or polymer coated . I use Neverseize on the threads. When I did a major upgrade of my pole mount, the stainless fasteners came right apart but all the zinc plated stuff came apart hard and on occasion I had to break them off. I buy boxes of stainless fasteners in bulk from a marine store and the cost is less per fastener than buying small quantities at hardware store. The quality is generally better.

All nuts should be nylock type self locking nuts, no lock washers. Lock washers are not much better than a regular washer in the long run and inevitably slow down assembly.

Even Gold Unistrut will start to rust eventually in outdoor conditions. Go with aluminum or stainless racking for the long run.

Spend the money on surge protectors and buy good ones. To date the Midnight Solar SPDs appear to be the best compromise between price and quality. Delta's may keep your house from burning down but don't seem to save equipment. (I got a surge from the power company and it cooked one of my inverters with a Delta on the AC side). I also believe in a dedicated surge suppressor at the panel prior to the wires heading into the house. Most microinverters advertise built in surge suppression but that only keeps the inverters from getting cooked, I believe in a dedicated suppressor to protect against a surge coming into the house from the panels. Installers tend to go cheap on surge protection and go with the minimum.

Solar isn't rocket science especially microinverter based systems. If you don't understand the basics or the contracts you are willing to sign ask more questions before you get to start a thread called "Solar Nightmare". Your learning should not come from the salesmen who are pushing you to sign.

[DanKegel]

Did you have lightning strikes?

[peakbagger]

Not yet, the reality is that there are no guarantees for direct lightning strikes. That's what insurance is for . I have had one direct strike hit on the pole that supplies my house and another surge a few years later that was caused by the utility.

[bcroe]

Use stainless steel fasteners, no carbon or zinc or polymer coated . I use Neverseize on the threads. When
I did a major upgrade of my pole mount, the stainless fasteners came right apart but all the zinc plated
stuff came apart hard and on occasion I had to break them off. I buy boxes of stainless fasteners in bulk
from a marine store and the cost is less per fastener than buying small quantities at hardware store. The
quality is generally better.

All nuts should be nylock type self locking nuts, no lock washers. Lock washers are not much better than a
regular washer in the long run and inevitably slow down assembly.

I'm in agreement with the above. However I elect not to use nylock type nut. Instead I use a second nut locked
against the first. It keeps the threads better covered, doesn't require turning under tension all the way down, and
I don't have to worry about the lifetime of nylon in the out doors. SS washers everywhere spread the tension some.
6061 aluminum seems to do quite well outdoors, and no reactions with my 18-8 stainless bolts. Just about anything
can be bought on line and delivered. Bruce Roe

[sensij]

Thanks for doing that for me! Stop by to pick out a beer from the fridge in the garage anytime.

I agree that the solar installation I have works as designed. I just wish the salesman would have been more forthcoming in making sure I understood that this was probably not going to cover 100% of my current use.

Thanks! The location looks beautiful... with a beer in hand, I don't think I'd leave willingly.

One more PVoutput feature to evaluate your system's performance... use the "insolation" view to see what it projects would be the clear sky output for your system, given the location and orientation inputs. Their model doesn't do a great job of accounting for array temperature (even if you include temp coefficient info) and has some other flaws, but is still a decent tool for managing expectations. In particular, the thermal component typically causes outperformance in the morning and evening and underperformance midday, when it is hottest.

I can't post a screenshot at the moment, but your system looks like it has something impairing performance in the afternoon/evening. Did your salesman/installer perform a Suneye evaluation, or something similar? If not, that might be what is truly responsible for the gap between your expectations and the actual output. With respect to the thread topic... having a solar access study performed should be something everyone does during the design stage, even when it looks like an installation *should* be shade free.

[skipro3]

Your system looks like it has something impairing performance in the afternoon/evening.

Sorta. If you look again at the photo of my installation, you'll see that there is a gable end on the house that is taller than the shed roof over the patio the solar panels are mounted on. Here's the photo again;



Late afternoon sun causes this wall to shade the top three panels around 3:30pm this time of year.

You can see from this photo; my house from Google Earth with a SunCalc sun positioning overlay that sunrise is fine but sunset looses just a little. Not much since the panels are on a 22.5 degree tilt at 160 degree azimuth and that sun is probably around 290 degrees. Just a bit of loss, maybe 600 watts for another hour tops.

[skipro3]

All nuts should be nylock type self locking nuts, no lock washers. Lock washers are not much better than a regular washer in the long run and inevitably slow down assembly.

Not on systems that use a star washer to break the anodize on the aluminum to make ground contact. On my installation, star washers are used to mount the Solaredge optimizers to the rails. This saves a lot of solid conductor copper from having to connect all the optimizers to ground. Now just a single copper solid conductor is tied to each rail, then each optimizer is grounded to the rail with the star washer.

I want to also just mention something about stainless steel fasteners.
The threads are pretty sensitive to stretching. That means; follow the manufacturer's torque specs. My installer used a battery operated driver to seat the nuts on the panel mounts, over tightening them. When I inspected, I took my torque wrench to the roof and the installation instructions that stipulated 7 foot pounds of torque on the nuts. They had so over tighten the nuts that the stainless bolt threads were stretched and the nuts would not come off. I stopped the project, called the labor manager and explained the problem. He said every bolt would be replaced. I told him he was failing to see the bigger picture; every one of the solar panels had been clamped down so hard the hardware was destroyed. He got quiet. Yes, I told him, I mean every panel needs to be replaced as they are no longer under the manufacture's warranty. I am sure that any warranty claim would be based on an inspection of the panel and it's obvious they were over tightened.
He was not happy. Didn't agree that they had to be replaced, so I called my sales contact and we went over the contract. Especially the part where THEY specified all materials would be installed to manufacturer's specifications. They could either replace the panels and the hardware, or I offered to allow them to back out of the contract. I had not paid them a dime yet as my contract stipulated first payment is upon completion of construction to my satisfaction.

I recommended the supervisor send someone out to the last several jobs these two gorillas installed and check for other damage. This isn't something you can just look at, you got to take a torque wrench and see what those nuts were tightened to. He evidently did take up my suggestion because when the new panels arrived, a new crew was there too. They told me the original guys were fired. I'm sorry to hear that, but if they knew they were supposed to install to manufacturer's specs, it's their own doing, not mine.

[kny]

Whoa, PG&E does the rate comparison for you? That is fantastic... but how are they accounting for the solar production, for which you don't have much history?

I (and others) wrote this code. PG&E had far and away the toughest rates to model. But, we ended up with a very flexible rates engine as a result.

[peakbagger]

I will edit my post to always follow the manufacturers recommendation

[bcroe]

Not on systems that use a star washer to break the anodize on the aluminum to make ground contact. On my installation, star washers are used to mount the Solaredge optimizers to the rails. This saves a lot of solid conductor copper from having to connect all the optimizers to ground. Now just a single copper solid conductor is tied to each rail, then each optimizer is grounded to the rail with the star washer.

I want to also just mention something about stainless steel fasteners.
The threads are pretty sensitive to stretching. That means; follow the manufacturer's torque specs. My installer used a battery operated driver to seat the nuts on the panel mounts, over tightening them. When I inspected, I took my torque wrench to the roof and the installation instructions that stipulated 7 foot pounds of torque on the nuts. They had so over tighten the nuts that the stainless bolt threads were stretched and the nuts would not come off.

every one of the solar panels had been clamped down so hard the hardware was destroyed.

Here there are special oxide piercing washers used between aluminum supports
and panels, at least one per piece. It doesn't affect the rest of the mounting
hardware. No Optimizers used.

I learned about gorillas when I got a car. At first I would have to repair their
repair, eventually I just took overall maintenance, i won't even let the tire place
mount rims on my car, did it by hand on my lift.

Of course there was quite a bit done wrong on my solar system. I
just let them do their thing and get the system going. Then I redid just about
everything above ground to my standards, also picking up all the hardware
they dropped. Yes SS threads distort, if abused. I wouldn't ask them to replace
panels though; they still performed fine. My primary objective was to get rid of
the work crew and get running as fast as possible, I'm used to taking care of
others mistakes (ask about my job). Bruce Roe

[sdold]

you got to take a torque wrench and see what those nuts were tightened to.

What's a good way to do this?

[skipro3]

What's a good way to do this?

If you are physically able, climb up there with a torque wrench yourself and check. If not, and you can observe from the ground, have him demonstrate on your randomly selected nuts with a wrench you confirmed is set to the correct torque setting.

The best way though, is to be there when they install and stop them if they are using battery operated power tools to drive home the nuts. Stop them and request that they show you the manufacturer's instructions on how to install the part in question. If they don't have those on hand at the site, don't let them proceed.

Remember; YOU ARE THE BOSS!!!
You get the final say in all things. Nothing happens unless agree and you permit. Never let some contractor tell you this is fine, or it's to code or some other dumb bull**** answer. The installation is to your satisfaction or they are fired. Make sure you tell the salesman that before you sign and that there is language that says payments are made at each stage based solely on your final satisfaction. This also means esthetics too. Something might be technically o.k. but look like crap. Do not pay them until you are satisfied. This is YOUR home, not some random construction site. They darn well better learn right up front that you are passionate about the esthetics of this project as much as you are about the functionality of this project.

Usually a salesman is quite happy that the home owner wants to be right there, watching every step and stopping when things are not to their satisfaction. Good companies what their customers to be satisfied and happy. Not disgruntled and upset.

I rant. Sorry. It's just that it's getting a little more difficult to find someone who sees their daily work as something they care to be proud of. When you interview potential solar companies, tell the salesman you'll be interviewing the labor before they start their job and if you don't think they have the skills, talent or desire to do the job YOUR way and to YOUR satisfaction, you'll be telling them to leave and calling for another crew or they can just pick up all these materials and leave.

A contract is a two-way street. It's there to ensure you get exactly what you want. If you don't see it in the contract, have them write it in. You can be sure as heck they are writing in all the stuff they want that protects them after all.

[sdold]

If you are physically able, climb up there with a torque wrench yourself and check.

Thanks. I didn't realize breakaway torque was close enough to make this determination.

[J.P.M.]

This is known as "thread galling". Causes /prevention/cures available on the net for the price of a search.

[skipro3]

Thanks. I didn't realize breakaway torque was close enough to make this determination.

You definately want a torque wrench that measures down to 7ftlbs. Inch pounds converted is X12. So 7 ft lb is 84 inch pounds. Get a wrench that is right-sized for the job, or better, you should just use theirs since they should have one that they are using to begin with. I told the installer's supervisor I would not require proof of calibration if they started the job with the right tools to begin with, but if there was doubt that they were doing the job to manufacturer's specs, I reserved to right to request it.

Once the solar company understands that you are not a rube, have some understanding of how the job is to be done right, they will pay closer attention.

Reminds me of a dialog on the TV show Big Bang Theory. The guys, 2 doctorates and an engineer were in a car that broke down. One asked the others, "Who knows anything about internal combustion engines?" They all said of course they do. Then the one asked, "who here knows how to FIX an internal combustion engine?" They replied no, not hardly, etc.
That's us as the owners; we should know about the solar, how it works, how it's supposed to be assembled, it's performance and how it is determined that it does meet it's specs. We don't necessarily know how to perform the mechanics of it. Otherwise, we would just do it. Or go down to Home Depot, hire some day laborers and run the job ourselves.

Solar is way too big of an investment, price-wise, to not know if you are getting quality and value for the materials, work performed and warranty performance.