Just a quick question about glass

[Photonfanatic]

Hi all, new here. I've already done much of the research on building my own solar panels. I've decided that I'd like to do it, but I have a question in regards to their longevity. Obviously, we all want our panels to last as long as possible. Well, I was wondering how good glass is at blocking UV, in the long term. I've been reading up on that subject, and it seems that fortunately, glass is pretty darn good at blocking UV. But, in the end, it does allow a small amount to pass through. Well, how long does this take to finally kill a photovoltaic panel? How long until the elements (uv included) finally take their toll on the panel and cause it to fail? I know you can use thicker glass, but is that going to interfere with the light passing through at all?

[Mike90250]

Glass is a necessary evil ! There is no substitute. Quartz lets too much UV through. Sapphire is wayyy too expensive. Tempered glass is good. Low iron (no green color on the edge) is better. Low iron tempered with anti-reflection coating is the best.
The other function (other than structural protection) is Water Vapor blocking. Nearly EVERYTHING lets water vapor through, which will ruin the PV cells. Paint, epoxy, silicone seal, 98% of all plastics - is all permeable to water vapor, which will find it's way in.

[Photonfanatic]

What about a way to let the water drain off, out the bottom? Possible? As for glass, I think we're lucky that its actually such a good UV blocker. If that's what people are actually using, anyway. Maybe I should have asked what the lest expensive, best method of building a housing for the panels is. That will actually last.

[russ]

What about a way to let the water drain off, out the bottom? Possible? As for glass, I think we're lucky that its actually such a good UV blocker. If that's what people are actually using, anyway. Maybe I should have asked what the lest expensive, best method of building a housing for the panels is. That will actually last.

If you have to drain the water out then the panel is dead - the water vapor is enough to cause corrosion.

[Photonfanatic]

So you're saying that no water of any kind (even vapor) can EVER get inside there? Is there a model of a good DIY case around this site somewhere?

[russ]

Maybe I should have asked what the lest expensive, best method of building a housing for the panels is. That will actually last.

That one is easy - there really isn't a cost effective way. At present you can buy factory panels for 75 cents a watt and less.

[Photonfanatic]

That one is easy - there really isn't a cost effective way. At present you can buy factory panels for 75 cents a watt and less.

So really, at this point, there isnt much of a reason for this sub forum to exist. Cause thats only $30 for a 40 watt panel. What other costs are involved? Please forgive my newb ignorance.

[SunEagle]

The DIY threads are there for people that want to learn about solar pv panels. You can produce a low cost panel using individuals cells that will produce some electricity. The problem is a lot of people think they can produce a better panel for much less than buying one. They have gotten this idea from youtube videos and people that sell the individual cells.

What they don't get told is that the DIY panels have a very high rate of failure for all kinds of reasons. The cells are not grade A. People make mistakes during the soldering. It is also nearly impossible to "seal" a panel from moisture without some very expensive equipment.

These and other issues make for a sub grade panel. Good for hobbyist but not for any practical long term use.

[inetdog]

So really, at this point, there isnt much of a reason for this sub forum to exist. Cause thats only $30 for a 40 watt panel. What other costs are involved? Please forgive my newb ignorance.

This did not get posted for some reason (browser not feeling good?) so here it is from AutoRestore....

The sub forum initially was relevant when the cost of factory assembled panels was much higher.
It continues to exist because of hobby interest in building a small number of panels or building small custom panels for specific applications.
For some people around the world there may also be local problems getting commercial panels which make up for the clear cost economy in buying rather than building for almost everyone else.

[Photonfanatic]

Thanks everyone for the information. I've learned so much already. But I would also like to ask a few related questions now that I've read this thread.

1. What particular brand of solar panel is commonly known as "the best"? Is there a company that is known for excellence?

2. Can someone please provide a link to the aforementioned panels that are 75 cents per watt? I looked around google but the prices seem to vary for some reason.

3. I have a 2,300 square foot house that I want to power with solar. Or at least, take a big bite out of the electric bill. There is some kind of law in TX that says they have to give you the same rate they charge, if you're putting power back on the grid. So how many of those inexpensive panels do you think I would need?

[inetdog]

There is some kind of law in TX that says they have to give you the same rate they charge, if you're putting power back on the grid.

There is no net metering law (what you are referring to) in TX, except within the Autonomous Republic of Austin. And the power rates in the rest of the state are so low that economic payback for PV is slow at best.

[Sunking]

There is some kind of law in TX that says they have to give you the same rate they charge, if you're putting power back on the grid. So how many of those inexpensive panels do you think I would need?

No there is no such law in TX except for the Left Coast Island of Austin. This is why electricity in TX is dirt cheap, your neighbors refuse to subsidize solar systems with artificially inflated taxes and electric rates. Only in Austin do they do that.

As for th erest of TX is completely dependent on the electric provider. Coops do not allow any grid tied period as it is a very bad investment for them. Others that do allow grid tied will only pay you wholesale for excess electricity (on th eorder of 5-cents per Kwh), and charge you 9-cents for what you buy. For those that do have voluntary Net Metering, will jack up the rates to make up for losses. For example your neighbor will pay 9-cents per Kwh. But you on grid tied will pay 13 cents both ways.

So you need to tap the breaks. Most likely if you go solar grid tied, all you will do is being paying a lot more for electricity. Many pay as much as 400% more than they do now because they take out a loan to pay for it. They go from paying TXU $100/month to paying TXU $50/month plus another $350/month loan payment for 10 years on top of that. You had better know what you are asking for.

Also in TX Solar systems do not add value to your property like they do in other states like California. Add a $30K system to your home in TX only adds $5K to the value of your home meaning you lost $25K in equity which will hurt when and if you go to sell your home. You could very likely being the one writing a check to close on selling your home instead of receiving a check. It is called being Up Side Down on your home which is a politically correct way of saying You Are Screwed.

[SunEagle]

No there is no such law in TX except for the Left Coast Island of Austin. This is why electricity in TX is dirt cheap, your neighbors refuse to subsidize solar systems with artificially inflated taxes and electric rates. Only in Austin do they do that.

As for th erest of TX is completely dependent on the electric provider. Coops do not allow any grid tied period as it is a very bad investment for them. Others that do allow grid tied will only pay you wholesale for excess electricity (on th eorder of 5-cents per Kwh), and charge you 9-cents for what you buy. For those that do have voluntary Net Metering, will jack up the rates to make up for losses. For example your neighbor will pay 9-cents per Kwh. But you on grid tied will pay 13 cents both ways.

So you need to tap the breaks. Most likely if you go solar grid tied, all you will do is being paying a lot more for electricity. Many pay as much as 400% more than they do now because they take out a loan to pay for it. They go from paying TXU $100/month to paying TXU $50/month plus another $350/month loan payment for 10 years on top of that. You had better know what you are asking for.

Also in TX Solar systems do not add value to your property like they do in other states like California. Add a $30K system to your home in TX only adds $5K to the value of your home meaning you lost $25K in equity which will hurt when and if you go to sell your home. You could very likely being the one writing a check to close on selling your home instead of receiving a check. It is called being Up Side Down on your home which is a politically correct way of saying You Are Screwed.

Darn those Oil Minded Texans. They have no sense of humor when it comes to soaking up the sunlight to produce energy.

[Sunking]

Darn those Oil Minded Texans. They have no sense of humor when it comes to soaking up the sunlight to produce energy.

We use tons of solar energy. We pipe it up from underground. TX is also the largest Renewable Energy generator in the world. We generate more wind Energy than anyone. We sell it to NM and LA at highly inflated prices so we can have cheap electricity.

[SunEagle]

We use tons of solar energy. We pipe it up from underground. TX is also the largest Renewable Energy generator in the world. We generate more wind Energy than anyone. We sell it to NM and LA at highly inflated prices so we can have cheap electricity.

Darn capitalists.

I have seen some of those wind and underground solar energy fields flying to the West coast. No question Texas has a lot of real estate and many forms of energy resources. All very impressive.