Do the Newer 180 Watt, 36 Cell Panels Actually Put Out that Much?

[Canine]

I see a few different manufacturers currently putting out 180 watt, 12 volt/36 cell panels. Is that 180 watt rating an exaggeration or is it accurate? Or do you lose something in the process? Some panels work better than others when not directly facing the sun. Do the 180 watt panels fall on their face when they aren't perpendicular to the sun or something like that? Another way to phrase that question is: Do the 180 watt panels have any shortcomings compared to other panels?

 

[Surly Biker]

I see a few different manufacturers currently putting out 180 watt, 12 volt/36 cell panels. Is that 180 watt rating an exaggeration or is it accurate? Or do you lose something in the process? Some panels work better than others when not directly facing the sun. Do the 180 watt panels fall on their face when they aren't perpendicular to the sun or something like that? Another way to phrase that question is: Do the 180 watt panels have any shortcomings compared to other panels?

My understanding is that panels are rated based on standard lab test environment of temperature, light intensity, angle, etc. In most real world conditions you won't get the rated output.  My nominal 630W flat mounted panels typically peak at about 50% output during winter, but I've seen them run briefly at 110% during intense summer conditions.

Assume average output is going to be well below the rated capacity, maybe 20-30% rating averaged over the 8-10 hour day.

The 36 cell size would be nice for vans and small installations. My 60 cell are 300W so 180W for a 36 cell panel sounds right.

 

[John TF]

With little to no info , from you , they " new 180 watt panels " are not all the same , 180 watt is not time related - more watts as newer types , even though as the decades go by , the panels in general are increasing in size / output , some of the newest are 300 , 400 watts + .
With an average warrantee of 20 , 25 yrs. , I think its too soon to tell about cheap chineeze stuff .
As touched on post above , there are a lot of variables on installation , time of year , atmospheric conditions that are major contributors to performance , more so than the size .
Give links , or at least some idea of what panels your talking about ?
Manufacture , model etc. / wattage is not useful as replacement for man. / mod.

 

[jimindenver]

At one time manufactures would give the numbers for the rated output of a panel AND the numbers that you could realistically expect. It was not for long but some were. John is correct that it will be rare that you actually see the numbers that are listed on the panel. The closest I have seen on my panels was a old 230 watt poly that was putting out 216 watts and briefly 221 watts with cloud effect at 10,000 feet in the Rockies. High, dry and cold will produce the best results, low, hot and humid the worse. Eventually I realized that it was not what my panels could put out in perfect situations but rather what they were putting out in the situations that I was in currently.

 

[Spaceman Spiff]

 . . . Is that 180 watt rating an exaggeration or is it accurate? Or do you lose something in the process? Some panels work better than others when not directly facing the sun. Do the 180 watt panels fall on their face when they aren't perpendicular to the sun or something like that? Another way to phrase that question is: Do the 180 watt panels have any shortcomings compared to other panels?

At the end of manufacturer panels are put on a flash table that measures output at a standard test condition (1000W/m simulated sunlight at 77ºF).  The output is recorded and the panels are sorted.  Unknown if a particular manufacturer tests all panels, a statistical sample, a random sample, or no test, or is honest about the results.  The National Renewable Energy Laboratory does test panels independently, but I don't know how complete their coverage is.  Assuming the manufacturer is honest, the panel will deliver 180W under ideal conditions you will seldom see.

The wattage of the panel should have nothing to do with its performance; choice of cell material (poly, mono, thin film), quality of components, quality of manufacture, and design of the assembly will all impact the output at other than standard test conditions.  Your questions lack enough information to say anything about them except that a 180W panel will give 180W at STC (from an honest manufacturer).

 

[frater secessus]

Is that 180 watt rating an exaggeration or is it accurate?

It's a lab test, so it's accurate.

Or do you lose something in the process?

Nothing that one doesn't lose with all panels. 

Do the 180 watt panels have any shortcomings compared to other panels?

[I totally misread the question -- deleting this part]

 

[DLTooley]

The technology, tried and tested, is pretty much the same for all size panels. There are two types worth looking at, polycrystalline and monocrystalline. Mono is a bit more efficient and hence smaller for the same wattage, but poly has some advantages besides price. I'd skip the 'amorphous' type.

The number of cells corresponds to voltage, as I understand it. All 12v panels have 36 cells. (If I got this wrong let me know!). There are some advantages for higher voltages, either in a single panel or a series wired installation, but you are less likely to benefit from those with a smaller system.

 

[Canine]

John TF, the three manufacturers that I know of that make a 180 watt, 36 cell panel are: Grape Solar, EcoWorthy, and AM Solar. Well, AM Solar isn't a manufacturer, but they stock a panel that perhaps is made for them. They are an RV solar system specialist, so that leads me to think the 180 watt panels they carry are of good quality and will perform well under RV like conditions.

I understand panels generally don't perform at their stated specs because we generally don't live in ideal laboratory conditions. However, having that rating is useful because it provides a consistent, relative point of reference when comparing panels. A 250 watt, 60 cell panel is going to perform better than a 190 watt, 60 cell panel.

I also understand there are many other factors that influence the performance of the panels. The quality of wire, the quality of the connections, type of controller, length of wire, the weather, etc. But all things being equal, some panels perform better than others. And those variances will stand out under different conditions. Some perform better than others in heat. Some perform better than others at a slant to the sun. Some perform better in cloudy conditions.

Many companies overstate, mislead, or flat out lie about their products to make a sale. Vehicle tow ratings come to mind. A truck can be rated to tow 12,000 pounds. Would I do that for most vehicles with that rating? NO WAY! Dog food is another one. Yes, it might have the minimum protein required by law, but that protein may come from plants not animals, which is misleading. The food may have the right amount of vitamins and minerals, but they may be synthetic supplements. The food may be advertised as having vitamin C. Sounds like a good supplement to have, right? No. Dogs make their own vitamin C. Unless the have a medical problem, dogs don't need vitamin C (ascorbic acid). The vitamin C doesn't hurt, nor does it help; it is a marketing ploy to get us to buy their product.

Which brings me to the 180 watt panel. That does seem like a lot. It is the same power as a 60 cell, 300 watt panel or a 72 cell, 360 watt panel, which are becoming more popular now. My 285 watts panels perform quite well and that's getting close to the 300 watt limit we see nowadays. Yet, when I see those higher numbers, I can't help but be skeptical and wonder if spending less money by getting a 36 cell, 140 watt panel is more effective in real world settings where ideal conditions are seldom met.

 

[John61CT]

No, the ratings are standardized so that overall, the different panels will output a similar percentage below the rated output in similar conditions.

So at a given voltage rating, take two setups

e.g. 9 smaller panels each rated 100w, vs

3 panels bigger panels rated 300w each,

will both put about the same AH per day into your batteries.

The key is getting as many watts total as possible on your roof, so the panels' watts per sq ft, and their length and width will be more important than watts rating.

That said, fewer panels makes mounting easier.

To benefit from MPPT efficiency higher **voltages** will help

 

[WalkaboutTed]

I have two of "those newer 180 watt" panels. Each is on their own charge controller. Along with three 100 watt panels on their own charge controller. It's difficult to tell with the different angles of the sun and shadows from the vents/AC/antenna, but since the panels are on separate charge controllers, I can see that the watts seem proportionate.

But as John mentioned above, I'm not going to make myself crazy worrying about the output. I shoved as much solar that I could squeeze in on my 16' trailer roof. I haven't gone below 96% since I set it up (per my battery monitor, A Victron BMV-700). I'm following the sledgehammer approach-have more solar than I'm likely to ever need 95% of the time-especially since I'll be in the sunny West.

Before I got the solar on the roof, I was getting along very well with 260 watts portable during the Winter solstice. So, if I'm under trees, I can use that. I will not have to plug in unless I want to run my air conditioner.
Ted

 

[jimindenver]

  I will not have to plug in unless I want to run my air conditioner.
Ted

I love seeing that

 

[Canine]

I enjoy hearing about first hand experiences. It sounds like if there is a difference, it is minor. I've had pretty good luck with all of my components. Nothing has failed me and has performed beyond my expectations. I'm thinking about getting some 180 watt panels, but things are working so amazingly well now I'm having a hard time changing anything. If I did make changes, I'd wait till I had some money, then get a smoking deal on some panels, then sell my current panels on the cheap. Now I feel comfortable with the performance.

 

[John61CT]

Canine, the way you're posting makes it impossible to tell which are your words vs those you're quoting.

 

[Canine]

Oh, yeah. Weird I didn't notice that. lol. Kind of annoying, really.