Finally installing PV on my roof in LA: day 1

[solar pete]

Have I been unprofessional, rude or personally abusive, or just straight in what I write ?

This forum is at least partially about opinions right ? I believe if you look at what I write, you'll find it's mostly responses in the form of information I've leaned or opinions I've formed over an engineering career, with some lame attempts at a bit of PG-13 humor thrown in 1X/awhile. It's not about what I think of someone as a person, and certainly not about personal attacks or dislike of someone. Seems to me to dislike someone, you must know something about them. I don't know any posters to this forum.

Dan's attitude and M.O. are of a type I've seen all my life, and spent more time than I'd like correcting their ignorant mistakes. Where I believe those attitudes and M.O.'s convey incorrect or dangerous information, I'll say so and/or offer counter opinions as warranted. I only do so in areas where I think I know what I'm talking about.

I do not believe I've been rude. I do believe I've offered constructive criticism as well as a some a lot of information some may have found useful, and have freely shared some of what I know about solar energy.

Having had a few minor admonitions from moderators in the somewhat distant past, but not much else, I plan no changes to the way I operate on this forum. If you disagree, let me know and I'll leave.

Geez, .....perhaps I should have writen in comic sans, I look forward to your 5 paragraph response

[J.P.M.]

now now, you two play nice or you will have to go to your rooms.

Have I been unprofessional, rude or personally abusive, or just straight in what I write ?

This forum is at least partially about opinions right ? I believe if you look at what I write, you'll find it's mostly responses in the form of information I've leaned or opinions I've formed over an engineering career, with some lame attempts at a bit of PG-13 humor thrown in 1X/awhile. It's not about what I think of someone as a person, and certainly not about personal attacks or dislike of someone. Seems to me to dislike someone, you must know something about them. I don't know any posters to this forum.

Dan's attitude and M.O. are of a type I've seen all my life, and spent more time than I'd like correcting their ignorant mistakes. Where I believe those attitudes and M.O.'s convey incorrect or dangerous information, I'll say so and/or offer counter opinions as warranted. I only do so in areas where I think I know what I'm talking about.

I do not believe I've been rude. I do believe I've offered constructive criticism as well as a some a lot of information some may have found useful, and have freely shared some of what I know about solar energy.

Having had a few minor admonitions from moderators in the somewhat distant past, but not much else, I plan no changes to the way I operate on this forum. If you disagree, let me know and I'll leave.

[DanKegel]

. I'm writing that you lack the knowledge and experience to do it in a way that that will yield meaningful results that can be a useful contribution to the existing body of knowledge.

A testable prediction! Let's see what happens.

[J.P.M.]

Are you saying that the basic idea of trying to understand and measure the front and back side contributions to the output of a handful of bifacial panels is poor thinking?

No, and that you would say that from what I've written says a lot to me about your lack of knowledge about that subject. I'm writing that you lack the knowledge and experience to do it in a way that that will yield meaningful results that can be a useful contribution to the existing body of knowledge.

[DanKegel]

Dad! Jimmy's accusing me of shooting frogs again!

[solar pete]

now now, you two play nice or you will have to go to your rooms.

[DanKegel]

When you do have something perhaps original such as now, it's full of poor thinking as anyone versed in the subject can see.

Are you saying that the basic idea of trying to understand and measure the front and back side contributions to the output of a handful of bifacial panels is poor thinking?

[J.P.M.]

Yes, you've said that many times. I'm not sure on what basis you came to that conclusion.

I'll enlighten you: Most everything you've written. IMO only, you seem to be better at repeating other's cherry picked ideas that fit your preconceived agenda than serious original contributions.

When you do have something perhaps original such as now, it's full of poor thinking as anyone versed in the subject can see.

I like nice clothes, but I know nothing about tailoring. So, I try not to bloviate about tailoring to someone who knows how to make clothes as I'm mostly ignorant about the craft and profession.

Take the hint and the advice and do with it as you please.

[DanKegel]

I do not believe you have the basics of engineering and science required to make the types of observations you seem to come up with.

Yes, you've said that many times. I'm not sure on what basis you came to that conclusion.

[J.P.M.]

Yes, I understand you think I'm an idiot.

One more time: Don't do my thinking for me.

FWIW, I have a rather unpopular opinion in that I happen to think most people are about equally intelligent. The difference is mostly what they do with the opportunities they're given. Lots more to that, but it's off topic.

As for any abilities you may have, whatever they may be, I do not believe you have the basics of engineering and science required to make the types of observations you seem to come up with. That makes what you write about technical issues less accurate and therefore less valuable, not to mention more troublesome for those of us (like me in this case) who clean up your perhaps well meaning spoor that does more harm than good. I'll give you the benefit of the doubt that you do that out of ignorance.

Sort of reminds me of the story about French researchers investigating frog physiology. They get a frog and fire a starting pistol off behind the frog, frightening it. They record it jumps 10 feet when the pistol is fired and report it as such in the research findings. They then cut one of the frog's back legs off, fire the gun once more and report that the frog jumps 5 feet. Next, they cut the frog's other back leg off and repeat the pistol firing. The frog doesn't jump. The research finding and the report states: Removing a frog's back legs causes deafness in frogs.

Know what your doing and study what's required before you assume you know something. I forgot more about what you seem to be attempting than I expect you'll know for some time. Learn from the mistakes of others. You won't live long enough to make them all yourself.

Take what you want of the above. Scrap the rest.

[DanKegel]

Those qualities without the knowledge required to use them

Yes, I understand you think I'm an idiot.

[J.P.M.]

Yep, I'm worried about temperature effects.

And I'm worried about solaredge monitoring accuracy.

I might start by just waiting a week or two, then extract data for each panel for each day from the logs,
write a filter to skip days without full sun,
grab ambient temperature data from the nearest weather station,
and see if I can get a repeatable and stable measure of corrected peak and total power in full sun.
If I get ambitious, I might add temperature sensors glued to the backsides of the panels.

I expect doing this right is harder than it sounds.

The temp. of a panel is dependent on more things than ambient airtemp. alone. To have any hope of a reasonable dart throw at some meaningful data, you'll need an onsite weather station, and some knowledge of what data is important as well as what to do with it.

Desire for answers and intellectual curiosity are admirable qualities. Those qualities without the knowledge required to use them is like a powerful locomotive with no flanges on the wheels.

IMO only, you need not only flanges, but track as well.

The amb. temp. on your roof will be quite different than the nearest weather station.

The solaredge monitoring accuracy, like most other panel monitoring is probably less than any of the variability in your other instrumentation. In any case, unless you have some way to measure or estimate that (monitoring) accuracy, it's a moot point.

Take readings at min. incidence angle on cloudless days. They will give the best chance of max. irradiance and will have the least minute/minute variation.

Temp. sensors "glued" to the backside of panels is pretty much useless without knowing how to estimate modifications to the readings. Their mass, especially relative to a PV panel, the way they change the heat transfer film coeff. between the air and the panel surface, the thermal resistance between the sensor and the surface through the attachment method - the "glue", as well as several other things, make any readings obtained via attached sensors, again without adjusting the raw data, pretty much useless. Do what you want, but know there's more going on and more things required than you know about.

Curiosity and desire for information by themselves do not guarantee meaningful results that reflect some accurate, useful and repeatable version of reality.

[DanKegel]

Thanks, I'll look for that effect.

[sensij]

The voltage at which the panel operates will give you some insight into the temperature. Even if it isn't accurate on an absolute scale, comparing a single panel's data to itself should be reasonably trustworthy. If the voltage moves much when either side of the panel is covered, that would mostly indicate a temperature effect... there is a small shift from the new mppt point, but temperature should dominate.

[DanKegel]

Yep, I'm worried about temperature effects.

And I'm worried about solaredge monitoring accuracy.

I might start by just waiting a week or two, then extract data for each panel for each day from the logs,
write a filter to skip days without full sun,
grab ambient temperature data from the nearest weather station,
and see if I can get a repeatable and stable measure of corrected peak and total power in full sun.
If I get ambitious, I might add temperature sensors glued to the backsides of the panels.

I expect doing this right is harder than it sounds.