best low light performance

HiTech wrote:

harold1946 wrote:
You read into it more than was stated. I said there were better choises for efficiency than Thin film amorphous panels which have the worst conversion efficiency rating in the PV industry, nothing more.
I rated the different types using the industry standard tier scale.
I was asked about what type of solar panels I have and answered that I have The Sony Hybrid. I made no personal claim, mearly stated they have the highest conversion efficiency rating in the industry, which can be varified.
I am not responsible for the reading comprehension or interpretation by others.
The consept of thin film technology is an exelent one and may yet prove to be the furure of PV. As presented in its current form it is the the highest cost per watt for the lowest return in output of anything in the industry, irrespective of available light.

If one wants to get very technical and dig into some interesting information, I suggest studying the affects of ambient temperature on PV panels.

Don't go there, thin film tends to do well ;) at least the Unisolars to (triple junction thin film, with each layer absorbing a different light frequency).
Jim

There you go again. I made no reference to Unisolar or any other thin film manufacturer with regard to doing or not doing well, but the parent company did file for bankruptcy and placed the Unisolar division up for sale. Possibly just poor management?

harold1946 wrote:
You read into it more than was stated. I said there were better choises for efficiency than Thin film amorphous panels which have the worst conversion efficiency rating in the PV industry, nothing more.
I rated the different types using the industry standard tier scale.
I was asked about what type of solar panels I have and answered that I have The Sony Hybrid. I made no personal claim, mearly stated they have the highest conversion efficiency rating in the industry, which can be varified.
I am not responsible for the reading comprehension or interpretation by others.
The consept of thin film technology is an exelent one and may yet prove to be the furure of PV. As presented in its current form it is the the highest cost per watt for the lowest return in output of anything in the industry, irrespective of available light.

If one wants to get very technical and dig into some interesting information, I suggest studying the affects of ambient temperature on PV panels.

Don't go there, thin film tends to do well ;) at least the Unisolars do (triple junction thin film, with each layer absorbing a different light frequency).

Jim

You read into it more than was stated. I said there were better choises for efficiency than Thin film amorphous panels which have the worst conversion efficiency rating in the PV industry, nothing more.
I rated the different types using the industry standard tier scale.
I was asked about what type of solar panels I have and answered that I have The Sony Hybrid. I made no personal claim, mearly stated they have the highest conversion efficiency rating in the industry, which can be varified.
I am not responsible for the reading comprehension or interpretation by others.
The consept of thin film technology is an exelent one and may yet prove to be the furure of PV. As presented in its current form it is the the highest cost per watt for the lowest return in output of anything in the industry, irrespective of available light.

If one wants to get very technical and dig into some interesting information, I suggest studying the affects of ambient temperature on PV panels.

No I am claiming the conversion efficiency is *not the measure* of low light efficiency as defined by percentage of full power output at a lower light level. We frequently discuss getting say 1 amp out of a 200w panel in low light. I've never seen anyone make a claim here that 1 amp from a square meter of panels is good, bad or indifferent. Unless I misunderstand your earlier points, you seemed to be bristling at claims of good low light performance for panels other than the type you bought. Nobody but you is making claims about low light performance per square meter that I recall. People are making claims about low light performance vs. nominal wattage rating.

I am also claiming that efficiency may get worse non linearly as lumens drop, and get worse on a different curve on different panels and types. No magic. No violations of the laws of physics.

HiTech wrote:

harold1946 wrote:
Hi Tech; Semantics again??
Is the definition of good in an RV application different than say a residential one?
Common sense tells one that efficiency of all PV drops off as light deminishes and varies by latitude and angle of installation, atmospheric conditions, no matter what the materials used in construction.

But common sense does not say the drop off is equal nor linear across two panels or panel types.
Agreed, and I would also include different manufacturers.

Yes an RV application is quite different. The RV moves from place to place and is subjected to a much larger and less predictable variation in light level and orientation than a residential install, where you can understand say partial shading and design for it very specifically.
:S

You can call definitions semantics, but I say you are hiding behind semantics to try to do an apples to oranges comparison, claiming that it is semantics to point out that an orange is not an apple. After all, they are both fruit. They must be the same, right?

Jim

Sinse there are four individual types of panels there is no choise but to compare apples to oranges, unless one considers all types to be equally conversion efficient, which they are not.
The option is to go with the most conversion efficient or something less. It has nothing to do with being lenier nor the amount of "drop off."
Using your logic implies that conversion efficiency can increase with deminishing light, which is contrary to physics.
Unless definitions follow logic and laws of physics they are wrong, are they not????

Can someone post the I-V curves of the panels? That way you could compare the low light performance of the different types of panels against one another using actual panel data.

harold1946 wrote:
Hi Tech; Semantics again??
Is the definition of good in an RV application different than say a residential one?
Common sense tells one that efficiency of all PV drops off as light deminishes and varies by latitude and angle of installation, atmospheric conditions, no matter what the materials used in construction.

But common sense does not say the drop off is equal nor linear across two panels or panel types.

Yes an RV application is quite different. The RV moves from place to place and is subjected to a much larger and less predictable variation in light level and orientation than a residential install, where you can understand say partial shading and design for it very specifically.

You can call definitions semantics, but I say you are hiding behind semantics to try to do an apples to oranges comparison, claiming that it is semantics to point out that an orange is not an apple. After all, they are both fruit. They must be the same, right?

Jim

pianotuna wrote:
Hi,

Let's get back on topic--which is Poly or Mono in low light.

We have a statement rule of thumb from a seller, that suggest mono gets the edge.

We have a real life test where the poly whipped the mono by a fairly substantial amount.

So folks poly or mono?

Just so as you know I will ask a mod to remove any post that does not address the above.

Lab testing and tier scale indicates poly.
Manufacturers and sales persons make many unsubstantiated claims.
If poly and mono are the only choices it would be poly.
Given the other alternative I would choose the hybrid with its higher conversion efficiency.
Does giving an alternative constitute failure to "address the above"?

One thing I've noticed is the poly is much more consistent in voltage than the mono is. The poly stays around 33-34v in low light where the mono will drop to 29v or so.
The mono does climb higher in bright light even though it doesn't produce as much amps. it's this variation in voltages between the panels in different light that I don't attempt to combine them even flat.

I still suggest that if you are picking them up to do simple test of VOC and Isc in different light. It may just be the brands of panels I'm using or a comparison of types of panels in spec vs real life.

harold,

I've asked the moderator to remove your last post.