Low Light PV Panels for Oregon Residents

[dlt123me]

Hello everyone. I live in the Pacific Northwest near Portland Oregon. The general climate here is usually overcast with rain showers during the winter months. We see the sun in the summer months but the winters are usually cloudy.

I am new to Solar Power and have decided to learn what I can and put together a small PV system for camping and eventually add to it later to supply power for a small RV. I am in the process of doing my research into this fascinating science and art.

As I've mentioned I live in Oregon and need to find a PV panel that can handle low light situations and still give a good output.

I've run into a panel called ET Solar which have 40-95 watt panel systems. Is anyone familiar with this panel or company and if so, what is your opinion? They say they are excellent in low light conditions, I assume they mean for overcast areas right?... or am I falling for marketing ploys?

Also, if anyone has suggestions for a low light panel please let me know. I am wanting to go with a 100 but <=150 watt panels since I will eventually be adding to my system as my funds allow.

This will be my first Solar project and I'm wanting to start by constructing a charging system that will charge a Schumacher PSJ-2212 DSR ProSeries 2200 Peak Amps Jump Starter and Portable Power Unit. This battery will be used to run my DC CPAP machine that I need for sleeping.

For this project, I probably do not need more than a 45 watt panel to charge it, but have decided to go 90+ watts which will help with building on for my future RV needs.

I am tired of having to camp with Land Line power and I really want to get away from camping in State parks, so my first Solar Power system will be used to charge this portable power unit.

I will be using a small 15 amp Morningstar Sunsaver MPPT charge controller to run this system... but am open for suggestions.

Any feedback and help is greatly appreciated. Thanks in advance for any feedback and suggestions.

Dennis

[billvon]

As I've mentioned I live in Oregon and need to find a PV panel that can handle low light situations and still give a good output.

No panel will "handle" clouds. They will all still work just fine converting light to electricity, but when only 5-25% of the light is getting through due to clouds, you're only going to get 5-25% of the panel's rated output.

[russ]

Charge a battery with your car's alternator.

[dlt123me]

No panel will "handle" clouds. They will all still work just fine converting light to electricity, but when only 5-25% of the light is getting through due to clouds, you're only going to get 5-25% of the panel's rated output.

That makes sense, but what do the panel manufacturers mean when they say "excellent performance under in low light environments"? Not all panels make this claim. Am I getting side tracked with marketing hype? Like I mentioned, I'm new to this sport.

Thanks for responding.

[dlt123me]

Charge a battery with your car's alternator.

I could do that but wanted to make a system that I could pack into a campsite without my car... That is why I am considering the Shumacher 22 amp Jump Start Portable Power Pack. I could use a solar panel and controller to charge my battery during the day of camping.

Dennis

[inetdog]

That makes sense, but what do the panel manufacturers mean when they say "excellent performance under in low light environments"? Not all panels make this claim. Am I getting side tracked with marketing hype? Like I mentioned, I'm new to this sport.

Thanks for responding.

Well, I think that there are two factors involved here:

1. Some types of panels are better at handling diffuse light (coming from all directions, including relatively shallow angles) than other types. (Monocrystaline are probably poorest.) They can justifiably claim better performance in low light than other types. But still, is that enough of a difference to make their use practical?
2. Others can claim excellent performance in low light, but what might that mean? That their efficiency is just as good in low light as in bright light, probably. But that does nothing to overcome the loss in power that comes from the reduced light level.

Marketing hype? A goodly amount, yes. With some small element of truth if you have a large enough area of panels and a small enough load requirement. But that will not be the case while camping.

[russ]

That makes sense, but what do the panel manufacturers mean when they say "excellent performance under in low light environments"? Not all panels make this claim. Am I getting side tracked with marketing hype? Like I mentioned, I'm new to this sport.

Thanks for responding.

PR hype - film may do marginally better but not enough to make a difference for you.

[Mike90250]

That makes sense, but what do the panel manufacturers mean when they say "excellent performance under in low light environments"? Not all panels make this claim. Am I getting side tracked with marketing hype? Like I mentioned, I'm new to this sport.

Thanks for responding.

"The paint on brand X car, will last longer if driven at low speeds."
Very hard to prove, or disprove. In anything less than full, bright sunlight, PV panels will all, produce far less power than their nameplate sticker. Amorphous panels DO produce a bit better under low light conditions, but have not proven themselves long term, as their power degrades measurably over time (much faster than poly or mono panels).

Ask the sales man for a web link to a "power vs light intensity" chart, that compares "his" panels, to other brands. Most likely, the chart does not exist. If it does, it's likely to be un-scaled, or comparing concentrator panels to magic panels. I'd like to see that link.

[Sunking]

Am I getting side tracked with marketing hype?

Yep you are hearing what you want to hear and looking for a source to tell you what you want to hear.

[Naptown]

Actually look at the Photon magazine ratings of panels.
Where they are tested is similar to where you are (gloomy)
REC and Siliken came out on top for harvest.
Sharp was at the bottom of the heap.
Now the trick is do they make a panel that you can use?

[billvon]

That makes sense, but what do the panel manufacturers mean when they say "excellent performance under in low light environments"?

It means that if you take a pyranometer (instrument that measures total insolation) and measure 20% insolation, then an "excellent performance under in low light environments" panel might give you 20% of its rated output while another might give you 17%. None will give you 25%.

[Naptown]

Another thing to do is to look at the IV curves of the module you are considering. Most manufacturers will give the curves for varying insolation.

[dlt123me]

Thanks everyone, I can see why there is so much debate about panels. I also understand why there is a thread here that is asking for what panel is best. There is really a lot of information one needs to wade through to get the the truth.

I really need to do more research into picking a panel. I appreciate everyone's suggestions and I'm just a little closer to understanding the in's and out's of panel selection.

If anyone has other links for how to choose panels, please let me know. It will also help others who find this thread.

Thanks all,
Dennis

[dlt123me]

Actually look at the Photon magazine ratings of panels.
Where they are tested is similar to where you are (gloomy)
REC and Siliken came out on top for harvest.
Sharp was at the bottom of the heap.
Now the trick is do they make a panel that you can use?

Unfortunately, you need to be a Photon Magazine subscriber to read any of their archived articles and the subscription fee is pretty steep. Thanks though.

Dennis

[inetdog]

Unfortunately, you need to be a Photon Magazine subscriber to read any of their archived articles and the subscription fee is pretty steep. Thanks though.

Dennis

Some of the information is available from the web sites of the winners. No details on the test conditions, etc. but the raw results are still helpful.