Inverter / system questions

[vinniethePVtech]

Many module manufacturers use AR glass. Yes this can increase efficiency during times of high angle of incidence. But has nothing to do with the performance drop of the cells themselves. If the losses of the module were based on loss of efficiency and not overall performance the losses would be higher on the high efffeccy module
10% of 18 =1.8
10% of 13.9 =1.39

You are almost starting to get it. Losses aren't larger on a higher efficiency because it is "higher in efficiency". When you understand that nonsense then saying losses of 1% between a 18% efficient pv module and a 13.9% module will start to make sense with the whole concept of "HIGH EFFICIENCY".

[Naptown]

The degradation is based on the rated panel output at STC and has not a single thing to do with conversion rates.
Show me some documented proof that supports your position. A 10% loss of output is a 10% loss of output module efficiency notwithstanding.

[vinniethePVtech]

The degradation is based on the rated panel output at STC and has not a single thing to do with conversion rates.
Show me some documented proof that supports your position. A 10% loss of output is a 10% loss of output module efficiency notwithstanding.

Pnom rating of the suntech power module on there data sheet. How ever sunpower does not supply the Pnom.

http://de.krannich-solar.com/fileadmin/content/data_sheets/solar_modules/STP_225-230P_156-60_20Wd_EN.pdf

Sunpower doesnt provide a pnom rating sheet for the life span of the module but you get the point with the data sheet. http://us.sunpowercorp.com/cs/BlobSe...ble=MungoBlobs

[Sunking]

If you get a 1% loss over 2 years that's a 1% loss of 18% or 13.9% not 100%, every one is assuming 100%. That makes conversion 17% efficient hypothetically for a sunpower, and a 12.9% efficient hypothetical for a suntech.

Vinny, honestly you are thinking too much, and making things more complicated than they really are. I have been designing and contract installation for about 13 years now. In that time have been involved with about 100 replacements give or take 10 units.

I use a lot of Kyocera and BP products and both have almost identical warranties which are reflected across the industry. Any legit manufacture has a X-Y-Z warranty where X = workmanship years, Y= 90% power years, and Z = 80% year power output of specified STC rated output. Kyocera current KD series is a standard 5-10-20 which is the common warranty unless you negotiate better terms.

Kyocera' warranty is

5 years workmanship
10 year 90% STC
20 year 80% STC

Here is the link to Kyocera's warranty and is as follows:

[I]A. Five Year Limited PV Module(s) Warranty
Kyocera warrants the PV Module(s) to be free from the defects and/or failures specified below
for a period not exceeding five (5) years from the date of sale to the original customer
(“Customer”):
1) defects and/or failures due to manufacturing;
2) defects and/or failures due to materials;
3) cracking of the front glass surface due to foreign objects inside the glass; or
Note: This limited warranty shall exclude cracking of the front glass surface due to
external shock from flying objects or external stress.
4) non-conformity to specifications due to faulty manufacturing and/or inspection processes.
If the PV Module(s) fails to conform to this warranty, Kyocera will repair or replace the PV
Module(s), at Kyocera’s sole option.

B. Limited Power Output Warranty of 20 years (90% / 80%)
Subject to Kyocera determining in its sole discretion that any power loss is due solely to defects
in materials or workmanship, Kyocera warrants the power output of the PV Module(s) as
follows:
Kyocera warrants that if, (a) within the first ten (10) years from the date of sale to the Customer,
the PV Module(s) exhibits a power output of less than ninety percent (90%) of the original
minimum rated power specified at the time of sale*,or (b) within twenty (20) years from the date
of sale to the Customer, the PV Module(s) exhibits a power output of less than eighty percent
(80%) of the original minimum rated power specified at the time of sale*, Kyocera will deliver
additional PV Module(s) to replace the missing power output, or repair or replace the PV
Module(s), at Kyocera’s sole option.
*The power output values shall be those measured under Kyocera’s standard measurement
conditions as follows: (a) light spectrum of AM 1.5; (b) irradiation of 1,000w per m

[vinniethePVtech]

Vinny, honestly you are thinking too much, and making things more complicated than they really are.

Yeah I guess I am over thinking the principal behind conversion a tad too much. I guess I should just keep it to the Mmp, ImP, and VmP. However I'm just going to end it with conversion efficiency percentage is determined at time of STC. (Temprature, Sunlight, AGE are all factors of conversion efficiency) which determines Max power @ STC. That is all i am going to end it on.

[Sunking]

(Temprature, Sunlight, AGE are all factors of conversion efficiency) which determines Max power @ STC. That is all i am going to end it on.

Here is where you got off track. STC is a very specific set of test conditions only obtainable in a test lab. There is no wiggle room or variants. It is a radiance of 1000 watts/M^2, 25 C panel temperature, and less than 20% humidity.

So if the panel Pmax STC rating is +/- 5% of 135 watts means in warranty terms is 115 watts @ 10 years and 102 watts @ 20 years. FWIW conversion efficiency is not even in the picture.

[KRenn]

Once again I reiterate, efficiency is not the same thing as production. Panel efficiency is related to the physical dimensions of the panel. a 15% efficiency 225 watt modules and a 18% 225 watt module are going to have basically the same output. The 18% module will be slightly smaller in size, so if roof space is a major concern, then I'd go with the more efficient panel, otherwise it really doesn't matter. I've seen outputs from a wide variety of panels and generally there's not a huge amount of variation when account for efficiency. You'll pay more for a more efficient panel but if you don't have major roof limitations, then you're not really getting much of a return on the extra spending.

[vinniethePVtech]

Once again I reiterate, efficiency is not the same thing as production. Panel efficiency is related to the physical dimensions of the panel. a 15% efficiency 225 watt modules and a 18% 225 watt module are going to have basically the same output.

O.K so this is why I think too much. I'm not saying your wrong. How ever a smaller panel being mono crystalline will have greater production in max output at a smaller size than that of a poly crystalline of larger size. Correct? This is production in a smaller sq area.
A LARGER SURFACE area will be more prone and susceptible to having surface area fatigue and failure per sq/in. There is higher probability for failure in a larger surface area, than in a smaller surface area that makes the same pmax.
The more efficient, and smaller silicon wafers become, the less probability of failure fatigue, and longer life it becomes.
I'm basically on my own tangent at this point in time. No one gets it. Thats fine.

Don't say i didn't tell you so when in 2 years schott solar or sunpower release the 20% efficient PV with 30 year warranty. Its all about the efficiency in the package and improvement in mono crystalline that will far exceed poly.

[russ]

comments withing the post in italics.

How ever a smaller panel being mono crystalline will have greater production in max output at a smaller size than that of a poly crystalline of larger size. Correct? No - look at the efficiency numbers - 13% is 13% whether it is mono or poly

A LARGER SURFACE area will be more prone and susceptible to having surface area fatigue and failure per sq/in. This takes a bit of imagination to accept - and the difference in areas, if any, are so small that it is of little importance.

Don't say i didn't tell you so when in 2 years schott solar or sunpower release the 20% efficient PV with 30 year warranty. Its all about the efficiency in the package and improvement in mono crystalline that will far exceed poly. Could be - we will see and believe it when it happens - so far nothing like that has happened. This has been going on for near 50 years now?

[vinniethePVtech]

comments withing the post in italics.

That's funny schott is in production for a 20.2% pv. Didn't take 50 years now did it?

http://www.schottsolar.com/global/news/top-news/article/more-than-20-percent/

Poly consumes roughly 20% more surface area than mono crystalline. That's alot of surface area to consume when it comes to installing more than 100kwh. Once it's into large scale production into the megawatts you can experience first what I am talking about in deficiencies within sq/in. Sure people in residential that install a string or 2 on there roof don't see it that way.

This has gone way off topic.

[russ]

That's funny schott is in production for a 20.2% pv. Didn't take 50 years now did it?

http://www.schottsolar.com/global/news/top-news/article/more-than-20-percent/

Poly consumes roughly 20% more surface area than mono crystalline. That's alot of surface area to consume when it comes to installing more than 100kwh. Once it's into large scale production into the megawatts you can experience first what I am talking about in deficiencies within sq/in. Sure people in residential that install a string or 2 on there roof don't see it that way.

This has gone way off topic.

If I am to understand you, 13% poly and 13% mono somehow produce different amounts of power per unit area?

Boeing makes 40+% cells - no big deal. They are a bit expensive. I was referring to your proclamation that one type of cell will suddenly beging to perform so much better than another - Schotts 20% cell is not the first by any means.

You are going down a strange road - inventing science along the way.

Anything used on a large scale points out the importance of efficiency and reliability.

[vinniethePVtech]

You are going down a strange road - inventing science along the way.

Being unorthodox to protocols and agendas is not reinventing science. People generally don't rationalize with a much broader picture and perspective to see clearly.

I am definitely not normal. Doesn't mean my statements don't have validity either.

[vinniethePVtech]

O.k so hopefully I can clear up some of this mess I started.
Here is proof of an e ample of what I am trying to explain in conversion effIciency and maybe I was jumbled up with the information.
So to start with clarity.
Sunpower makes a 215 pv panel with 72 black cells
Sunpower makes a 225 pv panel with 72 black cells with the addition of AR coating.

Apparently the AR coating applied to the 215w allows a 4.54% gain in pmax, now altering it to make it a UL listed 225w on name plate. Under STC a 225w has a 18.1% conversion efficiency. The 215w has a conversion efficiency of 17.2%
So taking 18.1% - 17.2% = .9% difference in conversion efficiency . So looking at a gain in efficiency , look backwards at deficiency. For every .9% lost in conversion, that's a loss of 10w when measured by surface area.

[Naptown]

Actually that has more to do with cell sorting than the AR coating. Not to knock the AR coating but I would hesitate to make the claim that that alone is the sole difference.
My justification for this is many manufacturers produce modules that are the exact same size and cell count. Yet they have different watt ratings.
This is because the cell sorting picks the higher producing cells for the higher power modules and it goes down from there.
I would also imagine that the AR coating is eventually going to wear away due to weathering. This if it were the major contributing cause to the increased efficiency would degrade output at a higher rate than without it and simple cell degradation.
I am going to take a wild guess here but it seems that you have drunk the Sunpower kool aid.

[vinniethePVtech]

Actually that has more to do with cell sorting than the AR coating. Not to knock the AR coating but I would hesitate to make the claim that that alone is the sole difference.
My justification for this is many manufacturers produce modules that are the exact same size and cell count. Yet they have different watt ratings.
I am going to take a wild guess here but it seems that you have drunk the Sunpower kool aid.

Dude do you know where I work from looking at my bio?
Where do you think I get specs, and patent info from. The patent of the 215 is the same as the 225 with the addition of AR coating. It's the same panel specs plus AR coating. No deceptiveness it's a UL listed patent that has been tested under STC of both conditions. The 215 is rebadged as a 225 with new UL based on STC.