They’re all (mostly) the same…on the outside.
Solar panel technology has gotten so inexpensive that even the tightest budgets can do it. The solar panels on my roof cost about $2.50/watt ten years ago. Today I could replace every one of them for less than half that. In some cases they come in at less than $1.00/watt! It got that good that fast! Solar panels are also a lot easier to find. They used to be a niche product sold only by a few distributors. Today…they’re ubiquitous on Amazon and eBay and even local hardware stores.
So when a radio amateur decides to jump off the grid, it’s easy to choose any panel in the desired power and price range. Click, click, click…it shows up at the door in a day or two, for not a whole lot of money. Before indulging in the buffet of solar panel options, it’s helpful to have some working knowledge of the different types.
1: Thin film Solar
Thin film solar panels are the most common and least expensive. They are made by applying a silicon film to a flexible substrate such as plastic. This allows the panel to be folded or shaped to uneven surfaces. However, not all thin film panels are bendable. Some versions are on a hardened backing.
The tradeoffs: First, less efficiency. Amorphous silicon, which accounts for the vast majority of thin film panels, will not produce as much power as other panels of the same physical size. Don’t read too much into this, though. The difference is not so great as to make a big difference to off grid radio applications. Second, thin film panels do not have as long a service life as the rest. While conventional solar panels can last twenty years or more, thin panels will need to be replaced sooner. Again, for the average ham, this is not a major consideration.
Variations on thin film solar panels.
Thin film solar comes in three basic varieties:
- amorphous silicon
- cadmium telluride
- copper indium gallium selenide
Thin film panels more or less all look the same, so there is no way to tell which flavor you have from outward appearances. If chemical makeup information is available, steer away from cadmium telluride. The panels work just fine but cadmium is a highly toxic heavy metal and difficult to dispose of ethically at the end of the panel service life. Cadmium telluride accounts for only about 5% of thin film production and nearly all of that is for commercial installations, so you’re not likely to run into it.
Copper indium gallium selenide panels are also marketed as “CIGS” or “CIS” panels. It’s a really great technology with an efficiency & price point as good or better than mono crystalline panels. The infamous Solyndra corporation was a major producer of CIS panels before they were tangled in a Federal fraud investigation and went out of business. Other manufacturers produce them but you’ll have to dig around as they are not very common.
STOCK PHOTO
2. Mono crystalline solar panels.
Mono crystal panels are at the top of the solar panel pyramid. They are the most efficient, and as you might guess, the most expensive. They are made from slicing silicon from larger bricks or ingots and can be identified by their uniform color. This process produces some waste, so of course that gets factored into the cost. The uninterrupted repeating crystal structures within the slices is why these panels are more efficient.
The latest data I could find indicates that mono crystalline panels are the second-best selling type of panel globally. However, the data is several years old and since then the cost of mono crystalline solar panels has come down. Monos are only slightly more expensive and sometimes equal to other technologies.
There are not a whole lot of disadvantages to mono crystalline solar panels, other than the cost. Another consideration is the sizes available. Getting a mono in lower wattages that many hams use (less than 50 watts) is certainly possible, but the dollars-per-watt goes up as the size of the panel goes down, and flexibility may be an issue. By flexibility I mean the transport and use of the panel.
Monos are usually built into an aluminum frame. While there are a few exceptions, they typically cannot be rolled up or folded, so the size and shape you get is what you’ll have to physically fit into your system.
3. Poly crystalline solar panels.
Poly crystal panels a are a great balance of power and price, making them an excellent “bang for the buck”. I use them myself for my large home installation.
Polys are manufactured by pouring melted silicon into molds. The resulting silicon crystal structure is uneven and random, giving the finished solar panel a characteristic metal flake or “broken glass” appearance of varying blue shades.
The main disadvantage to poly crystal solar panels is the lowered efficiency compared to monos. Because of this, a poly will be slightly larger than a mono of the same power output. The inefficiency does come with a lower cost, so you are getting something in the tradeoff. The difference in size is not significant and should not be an issue unless you are so tight for space that even a inch or two matters. Polys are also typically made with an aluminum frame. Like monos, in most cases they are a fixed size and shape.
Poly crystallines are easily the most popular type of solar panel on the market. With retail panels regularly dipping below $1.00/watt (a target price that would have been unheard of just a few years ago), they are a fantastic value for the money. Unless you can find monos on sale for comparable prices, polys should be the first choice for the off grid amateur.
4. Perovskite, the solar power version of “vaporware”?
Way back in 2017 I posted an article about emerging perovskite solar technology. At the time it was still in the experimental stages and (we were told) it would be on the market soon. I’m not sure how others define “soon” but here we are nearly five years later and perovskite solar is nowhere in sight.
There are a lot of whispers and rumors, yet no actual product. “Click bait and switch” trickery is alive and well, though: I found one ad by an on line retailer proclaiming, “Seriously, we have perovskite solar!”. Then when I clicked on the ad, it sent me to a page of legacy technology solar panels that one can find anywhere.
I’m including perovskite on this list because I believe it will ultimately become available to us regular folks. Until then, keep it on your radar. If anyone knows of a retail source for perovskite solar, please tip me off because I’d love to get my hands on one and write an article about it.
Where to go from here.
Economies of scale and improved manufacturing processes have pushed solar energy to a place where almost any radio amateur can afford it. Even with all these good deals going on, it’s in your best interest to know the difference between the different types of panels and understand what you’re buying.
Choose thin film solar if:
- You want a solar panel that can fold, roll, or bend.
- You have low power needs and do not expect to expand your system.
- Are willing to sacrifice efficiency for physical flexibility (fold/roll/bend).
Choose mono crystalline solar if:
- Efficiency is a top priority.
- You have the budget.
- Physical space is restricted and you need to squeeze the most power out of every square inch.
- You are ok with having rigid, fixed-size panels that cannot be rolled, folded, or bent.
Choose poly-crystalline solar if:
- You are budget-conscious and are looking for the best “bang for the buck”.
- Physical space is not critical.
- You are ok with having rigid, fixed-size panels that cannot be folded, rolled, or bent.
The cost differences between mono and poly crystalline solar panels has tightened to the point that it is not too hard to find mono panels priced very close to or even lower lower than polys. Shop around…you may find some champaign for a beer price!
Thanks for providing this information, you did a great job with explaining the differnt types. How about informing us on what else to use in a DIY solar installation enough to power our radio shacks…and maybe a toaster oven.
Keep up the good work and thanks for your efforts.
Hello, Phil. Thanks for your supportive comments. Everything you need to know about taking your radio shack off the grid can be found right here on this website. Of course, there are other great resources, but obviously I’m biased.
But you do brig up a valid point in that it might be a good idea to come up with a condensed all-in-one article that lays out the basics for people who may otherwise get lost in the sea of information out there.
Thanks again for your input and I hope you’ll stop by Off Grid Ham again soon.
Thanks, this information will be used.
De wb5eat
Thanks for your support, Bob. I hope you’ll stop by again soon.
Thanks Chris. I have to admit I hadn’t a clue as to the differences between the different types of panels, but I only have one foldable solar panel (actually 4 or 5 individual panels in a briefcase sized package that unfolds) at the moment that’s used to top up the charge on the 20 Ah battery I use. I took a quick peak and that turns out to be the monocrystalline variety. I do know the one I have works reasonably well. The panel still puts about about 20% – 30% of its rated power even in pretty heavy cloud cover.
After spending an hour running and prepping my big Generac gasoline generator for winter a couple of weeks ago I’m starting to seriously consider one of these pre-built “whole house” battery packs. I need to run some calculations about capacities and all that. But it looks like one that would keep the fridge, freezer, furnace, a few lights, and sump pump going, plus occasional use of a coffee maker and microwave, for about 10 – 12 hours, is in the $5,000 – $7,000 range right now. I need to run some calculations one of these days about how cost effective something like that would really be, how much a solar system to charge it would cost, etc.
Hey Randall. My home solar setup was not intended to support an entire house, but if needed it could be adapted. It would not be business as usual, but in addition to my radio gear I could run some lights at night, keep the food cold, and other basic functions. I admit I never looked into those whole house batteries. Battery technology is advancing quickly so I think you’ll see them more and more.
One thing I am nervous about is how the electrical grid is going to handle the introduction of all these electric vehicles and other devices. The grid is already aging, stressed and fragile, and we’re about to add a massive load to the system in the form of electric vehicles, electric heat (it looks like California is well on the way to banning natural gas furnaces and cooking equipment, along with gas powered lawn equipment), etc. And right now there is no way our electrical distribution and generating systems can handle that kind of load. And here in Wisconsin at least it seems we can’t even build just a new power line to expand or replace a failing distribution system without immediately getting hit with dozens of lawsuits. It’s going to be interesting over the next few years as we try to transition away from gasoline, diesel, etc.
It’s a bit ironic that the very same environmentalists who are demanding we switch from fossil fuels to electric, something I think we do need to do, by the way, are also trying to prevent us from building the electrical distribution systems we’ll need to deal with the increased electric demands.
You are correct about the power grid and its inability to handle all the hopes and dreams that electric car proponents are trying to sell. Although I believe in solar and other “alternative” energy sources, I even more so believe they should never be mandated. The push for electric cars, for example, is more about political goals than legitimate consumer demand, and I think that’s dangerous territory to be in. After all, if electric cars are so great, then why does the government offer big tax breaks and kickbacks to incentivize people to buy them? If a product cannot be sold on its own merits then it deserves to die.
I want to stop there because we’re drifting too far from the scope and purpose of this blog, but your point is well taken and I appreciate your comments.
I’m on the waiting list for an LG battery. I went ahead and got the grid-tie solar panels and inverter installed over the summer and had everything spec’ed out for the battery when it comes in. Most of them will not run an entire home at peak. Mine will be a 10 KWh battery which should run everything but the drier and range. I have gas heat and a swamp cooler so as long as I don’t feel the need to dry clothes or cook a roast when the power is out I should be fine, although it will be interesting to see if it will be able to run the house indefinitely in the summertime. Your generator is probably still the way to go, especially if your heat requires more electricity than a circulator pump motor.
There’s only one company which makes amorphous silicon solar panels and that’s powerfilm solar. Why didn’t you mention them in this blog? At best your article seems subjective. This isn’t normal from you, what’s up?
73
Julian oh8stn
Hi Julian, for starters thanks for stopping by my blog. I am familiar with your YouTube channel and you have my respect.
As for not identifying Powerfilm Solar, the purpose of this article was to give a general overview of the different types of solar panels. I guess I could have mentioned specific manufacturers, but omitting them does not take anything away from the informational value of my blog post.
I do have my personal biases just like everyone else and certainly reserve the right to editorialize on my own blog and include (or exclude) details at my sole discretion. Still, I make a conscious effort not to let my biases get in the way of providing practical information that hams can apply to their own activities and expect positive results. This was a straightforward piece about the different types of solar panels. I’m unclear as to how it could be considered overly “subjective”.
I hope this explanation is satisfactory. Julian, once again I respect your contributions to the radio amateur community and I invite you to stop by again soon.
I have an interesting side note that is almost related to this. A friend of mine picked up dozens of large commercial solar panels that were supposed to go into an upscale housing development but were rejected by the contractor because the color didn’t match. At the moment I know nothing about them but I was thinking a few of those would look really good on the roof of my garage and I’m going to see if I can snag a few from him. I wouldn’t have space for a “whole house” set up but a few of them along with batteries and an inverter would be more than enough to probably power my entire radio shack and little “mad scientist” lab down in the basement. If anything ever comes of it I’ll let you know. Complicating things is he’s supposed to be moving to Spain in a few weeks.
anyway, if I can get my hands on a few of them and can figure out how to mount them up on the roof I might be getting in touch with you for some advice because my current experience with solar has been using pre-built complete packages or just fiddling around.