Are DIY Solar Panels Worth it?

[SolarTekkie]

Please post some pics of your build when you get a chance! I don't work in the industry at all, I was simply scared away by the thought of my house on fire with no insurance to replace it.

Couple problems here though;

1. Are you authorized to be grid tied by your local hydro? I believe you need a letter and approval from them in order to supply power.
2. The cheap grid tie inverters (sub-2000 dollar ones they use professionally) can cause dirty sinewaves and if the hydro company finds the source they will fine you harshly. If this is one of the ones that looks like a car amplifier or a inverter, I would cease using it.
3. Are you mounting this panel on your house? at 20-40v you are going to be pushing how many amps through those tiny bus wires, around 25+? If your house catches fire as an adjuster you should know already the insurance company is not going to cover that fire.

I have 2 panels I built myself and one of them is mounted outside away from my house and charges a battery bank, I thought I had that sucker sealed really well but it has warped horribly and looks like crap after only a couple months, luckily it's only a 5x5 panel of 6x6" cells the cheaper of the two. I am glad I didn't mount it on my roof, that's for sure.

-M

[rhjames]

Flashyeight - I think you has misunderstood some of the comments. They have tried to put reality into this. It's difficult to build a good panel that will last 25 years cheaper than you can buy one. It's not to discourage people who enjoy the achievement of DIY - just to make people realise that it's probably not cost effective.

Solar generation is very expensive electricity, even when put back to the grid, unless there is government (taxpayer subsidy) for it. For that reason, I don't do it - I don't want my neighbors paying for my electricity. My panels are sent to remote areas. That's a personal decision we each make. I would heed the warnings of connecting to the grid. This normally requires some expensive equipment if it's done correctly and legally.

Now to the panels. To be anything like cost effective, they need to last about 25 years. I use 4mm tempered glass, to ensure they survive that once every 10 year heavy hail storm - make sure your glass can stand up to whatever nature throws at them. You say you have siliconed the cells to the glass. You now have to get slyguard to protect the cells from air attack. You have to make this flow under and over every cell, excluding all air. You may not find this so easy, particularly with silicone in the way. This is important if you want to get acceptable life. Note that if you try to push out air bubbles, you risk cracking a cell, and I've found out the hard way, it's a nightmare to solder in a replacement while the slyguard is setting.

Why did you connect all the cells in series? Your research should have told you that it's normal to connect 36 cells in series for each panel, to give 20V under full sunlight, and over 14V (enough to charge a battery) under reduced sunlight (eg - when the sun's at a low angle). You are better off having two panels, each of 36 cells, connected in parallel. This would give you double the power.

Don't get too excited about 60W back into the grid. That's one small light globe for about 20% of the time (6 hours/day 300 days per year - allowing for rainy days.) That's not much power for 100 cells (others might have an idea of this - perhaps it's right considering the losses in an inverter etc).

Anyway, enjoy the project - it's a fun thing to achieve if you're like many of us here and can appreciate it for the experience. Just don't expect it to save you any money. I'm looking forward to your comments after you use the Slyguard.

[Flashyeight]

Why did you connect all the cells in series? Your research should have told you that it's normal to connect 36 cells in series for each panel, to give 20V under full sunlight, and over 14V (enough to charge a battery) under reduced sunlight (eg - when the sun's at a low angle). You are better off having two panels, each of 36 cells, connected in parallel. This would give you double the power.

Don't get too excited about 60W back into the grid. That's one small light globe for about 20% of the time (6 hours/day 300 days per year - allowing for rainy days.) That's not much power for 100 cells (others might have an idea of this - perhaps it's right considering the losses in an inverter etc).

.

I connected them thinking that the more connected they are the more power I could receive. Which I later found out that it wasn't the case. I found that sure my voltage goes up but my overall power is worse and they would not be able to be hooked up to a grid tie inverter because of the high dc voltage. I am currently going to try the 50 cell configuration to see if that works out the best. They also make a 72 cell panel which is why I thought in my mind the more cells per panel the better. I didn't find in my research that more cells hooked together does not necessarly mean more power. So I learned my lesson about that with only having to destroy 8 cells after taking them off.
I am not too excited about only getting 60W, I am actually disappointed because I should be getting 90w from the 50 cell panel (1.8 watts per cell times 50cells). I think I will be able to get this up by using better cells and having them installed better, we'll see. I'm excited to find out what the two 50 cell panels hooked in parrellel will do. If I find that it is much cheaper to build my own panels then i will proceed into finding out what my local electricity company requires to have for a grid tie system.

[Sunking]

I am not too excited about only getting 60W, I am actually disappointed because I should be getting 90w from the 50 cell panel (1.8 watts per cell times 50cells).

Lot less expensive to just buy a panel. Now on your second pass you have now spent more on failures and tries. I promise you any panel you will make will fail.

[Offgrid]

Lot less expensive to just buy a panel. Now on your second pass you have now spent more on failures and tries. I promise you any panel you will make will fail.

Sunking is on the money...been there...felt the pain.

[rhjames]

Flashyeight. You need to understand that you are putting power into electronic equipment that is designed for a certain input voltage - eg 12V. If you try to put 20V in, it basically just wastes 8V, so you don't necessarily get any more power than a 12V system. (This may not be exactly correct, but the concept remains). Check the 72 cell panel you mentioned - you may find that it's two lots of series 36 cells with the two connected in parallel.

You need to match all your equipment. It's no use trying to put 60W or 90W into the grid. The equipment to do it costs thousands of dollars. If you're prepared to spend this sort of money, you need to do it right. I suggest that you don't have the electrical knowledge to work all this out, so I suggest getting some professional assistance. Shops that sell some of this equipment - eg solar cells, inverters, and grid connection equipment may help. I think you are still on the wrong track with 50 cells in series.

Others here have much more experience than me, so hopefully you'll get more advice. From my experience, 36 cells is all that should be connected in series for most applications, aiming for 18 - 20V maximum.

[john p]

The best and sefest use for home made solar panels is to use them to make interesting coffee tables. or if made with very nice wood frames can be hung on interior walls like paintings.

[rhjames]

The best and safest use for home made solar panels is to use them to make interesting coffee tables. or if made with very nice wood frames can be hung on interior walls like paintings.

That sounds slightly negative. However, I agree that when you start to get up to medium size units, running in excess of about 10 amps, you need to have a good working knowledge of electrical wiring - preferably an electrician license. Overloaded wires and connections, and faulty connections, is a real fire risk. Flashyeight, for example, certainly doesn't have the electrical knowledge to be getting into these levels, or playing with the grid.

You're not going to get electrocuted from panels at 20V, but once you get on the other side of an inverter, it's deadly. 20V will certainly start a fire with a few amps to support it. Try shorting a 12V car battery with some normal electrical cable if you want to see what I mean.

Flashyeight - please don't take this the wrong way - I mean this as a warning that you are not ready to play around with higher power levels without some expert guidance.

[john p]

RHJAMES YES it is a negative view but its the only way you are likely to get DIY panels to last 20 yrs..
As an experiment at work 2 of us took a whole day to make a panel using the best equipment and materials. Will the panel we made last 20 years.. at least.. but it was vacuum sealed in a machine and sealed with a compound better than can be commercially bought at any hardware store... And used anodised alluminum for frame and low iron tempered glass..Cost effective.. NO .. look at the time taken. Home builders dont have this type of machinery and in most cases good soldering and wiring skills.. And I dont see how it can be done cheaply and long term successfully..
Many on these sites say "my panels been working for months" big deal ,, thats not years.

[rhjames]

RHJAMES YES it is a negative view but its the only way you are likely to get DIY panels to last 20 yrs..
As an experiment at work 2 of us took a whole day to make a panel using the best equipment and materials. Will the panel we made last 20 years.. at least.. but it was vacuum sealed in a machine and sealed with a compound better than can be commercially bought at any hardware store...
Many on these sites say "my panels been working for months" big deal ,, thats not years.

I agree with all you say here. I even wonder how many commercial units will still be working in 20 years. How many have been around for 20 years to test their life?

However, most people here seem to acknowledge the point that it's better in all ways to buy commercial units except for one issue - the satisfaction of doing it yourself. It's right to warn people that it's not easy to get a good result, it isn't cost effective, and there are big safety issues.

[john p]

there are ways to accellerate degradation of panels.. Its done with motor vehicle parts that wear also and many other things.

[rhjames]

there are ways to accelerate degradation of panels.. Its done with motor vehicle parts that wear also and many other things.

Yes - they can go through temperature/humidity cycles etc. Mechanical wear is easier to simulate at an accelerated rate. Some things like corrosion and oxygen attack just take time, though elevated temperature can help. I'm doubtful that there are proven accelerated aging methods for solar panels. To prove a method, it would require testing varous methoods on a lot of panels, compared to normal use over 25 years. I'm looking at decades of research.

[noeladdison]

Nice post! People should realize that seeking the help of the professional solar company is more advantageous than doing it by themselves. If they are worrying about the expensive cost of installing Photovoltaic cells at you home or your business don't worry government is now offering incentives and subsidies to those people who wants to install solar power to their home.

[rhjames]

Nice post! People should realize that seeking the help of the professional solar company is more advantageous than doing it by themselves. If they are worrying about the expensive cost of installing Photovoltaic cells at you home or your business don't worry government is now offering incentives and subsidies to those people who wants to install solar power to their home.

The problem with government subsidy is that it's paid for out of our taxes. One way or the other, we (and our neighbours) pay for very expensive electricity. I looked at it, and out of all conscience, I couldn't do it. You say "don't worry", but half our recent electricity costs in Australia have gone towards the government subsidy for solar systems.

We hear of schools and community centres installing solar, and people get excited, but we're never told the real cost to tax payers. If they knew the real cost out of their pockets, they'd be horrified.

[russ]

don't worry government is now offering incentives and subsidies to those people who wants to install solar power to their home.

Not only tax money but borrowed tax money - borrowed from the Chinese if they are still willing.

The administration and the DOE is spending money like a drunken sailor (and just about as intelligently) right now. Every day or two I read another press release from the DOE about where more money is going and how wonderful they are for doing such a thing.