Hi,Amorphous panels are clearly the best for low light performance--but are relatively speaking huge.Does any one know if Poly or Mono are better in low light?

pianotuna wrote:Hi,Amorphous panels are clearly the best for low light performance--but are relatively speaking huge.Does any one know if Poly or Mono are better in low light?Define what is ment by best. :S Amorphous "thin film" is the least efficient of the three types, with Mono being the most efficient, and poly next. Amorphous is not capable of producing nearly as much power per square foot of area as the other two. Common sense would dictate that low light conditions would render Amorpous even less efficient.So to answer your question, both are better (more efficient) than amorphous, under all light conditions.

I might be off base on this but I think a high voltage series system with MPPT will outperform in low light conditions. And more watts per foot has to be worth something. Low light may also mean long shadows so that needs to be considered.

Hi harold,Apparently you don't understand the question.Let me restate it.Which is more efficient in low light. Mono, or Poly.harold1946 wrote:pianotuna wrote:Hi,Amorphous panels are clearly the best for low light performance--but are relatively speaking huge.Does any one know if Poly or Mono are better in low light?Define what is ment by best. :S Amorphous "thin film" is the least efficient of the three types, with Mono being the most efficient, and poly next. Amorphous is not capable of producing nearly as much power per square foot of area as the other two. Common sense would dictate that low light conditions would render Amorpous even less efficient.So to answer your question, both are better (more efficient) than amorphous, under all light conditions.

Hi smk,I'm looking at two panels. Same price, and same physical size. One is mono and does 240 watts. The other is Poly and does 245 watts. Both are 24 volt, so MPPT would be a requirement. BTW the price in Canada is just a smidgen over $1.09 per watt.smkettner wrote:I might be off base on this but I think a high voltage series system with MPPT will outperform in low light conditions. And more watts per foot has to be worth something. Low light may also mean long shadows so that needs to be considered.

pianotuna wrote:Hi harold,Apparently you don't understand the question.Let me restate it.Which is more efficient in low light. Mono, or Ploy.harold1946 wrote:pianotuna wrote:Hi,Amorphous panels are clearly the best for low light performance--but are relatively speaking huge.Does any one know if Poly or Mono are better in low light?Define what is ment by best. :S Amorphous "thin film" is the least efficient of the three types, with Mono being the most efficient, and poly next. Amorphous is not capable of producing nearly as much power per square foot of area as the other two. Common sense would dictate that low light conditions would render Amorpous even less efficient.So to answer your question, both are better (more efficient) than amorphous, under all light conditions.Apparently you do not understand the answer. :S The most efficient is Mono, then poly, then Amorphous, in that order; under all light conditions.

best low light performance | Good Sam Community

173 Replies

pianotuna
Nomad III
May 02, 2013
Hi mena,

The reason I chose Uni-solar was because of lack of glass. I do drive on gravel roads. The other reason was that I did have enough "real estate" on the roof to meet my original needs which was battery charging for 3 125 amp-hour 12 volt batteries. I've since added four more and still have just enough solar with bank switching.
mena661
Explorer
May 02, 2013
bdosborn wrote:
Designing a system for low light performance is very important to some RVrs but it's equally important that everything else that affects system performance is considered as well.
Thank you. This I can understand.
bdosborn
Explorer
May 02, 2013
mena661 wrote:
bdosborn, I have a MH and don't have enough roof space to put anything but the most watts I can fit. I really don't get the purpose of the Unisolars despite the explanations, charts and graphs. Of course, it could just be over my head. I won't rule that out.

The purpose of the charts and graphs is to get people to realize that they don't have to guess about the performance they can expect from a PV panel. It's all listed on the specifications from the manufacturer. Too often the discussion regrading PV panels on this forum degrade to some basic categories:

"I know a guy who..."
"No Sir!"
"I'm Telling!"

It often occurs when people get locked into their own viewpoint and can't see the forest through the trees. You need to look at your requirements for PV and factor in important things like usage, budget, roof space, when you camp, where you camp, tilt or not tilt, etc. There isn't a one-size-fits-all approach to PV, it needs to be designed to fit your particular needs. Designing a system for low light performance is very important to some RVrs but it's equally important that everything else that affects system performance is considered as well.

Bruce
full_mosey
Explorer
May 02, 2013
Salvo wrote:
John, do you have a spec link for your panel?

Sal

Sorry, no link.

It was purchased from sunelec.com on 2010-04-06, and apparently was a special order production overrun as it disappeared from their site when I went back to buy more. It was a perfect fit for my roof real estate.

The sticker specs are:
Volts 23.5/19.6
Amps 7.44/6.64
L/W 42 5/8" x 31 3/8"

19.6V x 6.64A = 130W

HTH;
John
Salvo
Explorer
May 02, 2013
John, do you have a spec link for your panel?

Sal
Salvo
Explorer
May 02, 2013
No, get your facts straight.

HiTech wrote:
68 watt Unisolar maybe?

Jim
full_mosey
Explorer
May 02, 2013
Salvo;

Adding my Sun 130W Mono on a 1m^2 adjusted basis I get:

*************** US64 *** 135W Kyrocera***Sun130W Mono
Max Power ***** 64W ********** 135W ****** 151(1)
Low Light ***** 16W *********** 22W ******* 24(2)

(1). The Mono outperforms.

(2). Using the Kyrocera efficiency, (22/135)*151 = 24.

Amorphous loses all around on a 1m^2 basis!

All;
There is no need to lock horns. A simple fact check will do!

HTH;
John
pnichols
Explorer II
May 02, 2013
The whole discussion above reminds me of one time when we were drycamping in a Walmart parking lot. I looked up at the light in the parking lot that we were parked under and wondered what kind of, and how many, solar panels it would take to charge up my batteries up by morning compliments of Walmart.

I think I've read of some posters getting power under moonlight from "solar" panels, but so far no mention of street lamps by the RV community. How much energy is wasted in this country from artificial light no one is using at the time? Maybe we need more motion activated light switches.
full_mosey
Explorer
May 02, 2013
HiTech wrote:
68 watt Unisolar maybe?

Jim

Length: 2849mm (112.1”), Width: 394mm (15.5”),

is 2.849 x .394 = 1.1225 m^2

Adjusting to 1m^2, 68W / 1.1225=60.6W

V.S. my 130W Mono

1.082 x .796 = 0.86m^2

Adjusting to 1m^2, 130W / 0.86 = 151W

I'm pretty sure the 151W will produce more Watts in low light on a roof real estate basis.

HTH;
John
HiTech
Explorer
May 02, 2013
68 watt Unisolar maybe?

Jim