PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world test.

[Mark42]

Having been confused and irritated by the conflicting stories I heard about the relative merits of ‘expensive’ versus ‘cheap’ PV panels, I decided to find out the truth for myself.

I have just fitted an 8kW installation on my shed roof, comprising one 4kW array of 16 x £177 Hengji Solar HJM250M-3232 panels, and one 4kW array of 16 x £343 Sanyo HIT-H250-E1 panels.

These are run via two totally separate, but identical, electrical systems, from a 4-core 10mm SWA DC line into two single-phase Diehl AKO Platinum 3800S inverters, feeding into the two AC phases via two Landis & Gyr PV30-108 generation meters, mounted side-by-side for easy comparison.

These two arrays, mounted side-by-side on the same South-facing roof, will give an ideal and un-arguable comparison. No sales BS, no hearsay and guesswork, just clear meter readings.

I was trained as a scientist. I perceive the world through scientific eyes. And I like experiments. Game on!

It will take a year to give an accurate answer, since the characteristics of both makes may result in one out-performing the other under certain seasonal conditions. Day length, temperature, light intensity variations, and so on.

This will be most interesting. I will contact the media, and both manufacturers in due course.

Obviously the long-term economic benefit of either system needs to be calculated with reference to the typical retail installation cost to a customer. Can any PV professionals on here give me a guide please? What would the usual retail price difference for a 4kW install be please? I don’t need commercially-sensitive details, just a typical difference in price. If I said £4,000 would I be far wrong?

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[babba]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

surely you must know what you paid for the installs..???

 

[Earthstore]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

What a fantastic experiment, there are so many permutaions that you could use, but this will prove something at least, in real terms.
As to the price differance, I would say a little less, around £3500, or somewhere around that figure.

Please keep us all informed as to how it is going, maybe the forum masters could give you your own post, that only you could post on, it would make it easy to follow.
But thankyou, and well done.

 

[Mark42]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

surely you must know what you paid for the installs..???

No, because it was a sub-contract deal tied in with other work, and my company supplied all materials which we ordered ourselves at trade prices. Plus for example we have our own digger and driver so did the groundworks ourselves. So I have no idea of what the 'real' relative costs would be if we has just said 'yes' to some cold-call PV salesman, in the manner of a ‘normal’ retail customer. Our total cost with a long SWA underground run was £16,339 inc VAT. I’m sure this is ‘cheap’ against retail for 8kW so is not a fair price on which to base the maths.

 

[Markc]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Certainly is a very exciting experiment you have going there. May be open a straw pole now with the installers here on which "we" think will be doing the best. No other veritable other than panel. I like it.

So my vote. Should I stay loyal to what I've been told is the best or perhaps throw a swing vote for an unknown? What would I put my money on?

Sorry to say the sales BS is inbred now so Sanyo for me.

Please let us know how it goes. It's been some time since anything in the PV field has raised any form of interest but this certainly has for me.

Well done and good luck with it all.

 

[Mark42]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

What a fantastic experiment ...

Thank you for your kind comments, much appreciated!

Any ideas on how the experiment could be refined, or possible experimental error designed out, do say.

The idea of a comparative test only occurred to me at the last moment, after 16 of the planned 32 HJ's had already been installed. I immediately flogged the remaining 16 HJ’s on EBay, and ordered 16 Sanyos instead

Had it been planned from scratch, I’d have alternated HJs and Sanyos on the roof, and extended the wiring looms between alternate panels. But I think side-by-side complete arrays is good enough. Any slight difference in solar exposure due to position should not be statistically significant.

 

[screwdriver]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

I notice that there seems to be some shading in the photos, how where you thinking of creating fair test conditions? cut down the trees or swap the panels from one side to the other after a year? even the early morning late evening shadows could affect the results significantly!

 

[Vegelen]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Q/ Why do people put expensive solar pv panels in poor locations, surrounded by trees with lots of shade potential?
A/ They act before they think.
To add insult to injury, they then install them with inverters not preferentially designed to work well in shady conditions.
You can install solar pv panels with world beating technology, but if you dont choose your installation location wisely you are wasting your time.
Such comparitive tests between 2 different solar panels are best done in installation locations with minimal shading issues to get a fairer test result.
Your photo's clearly show that you've got shading issues.
When the trees gain leaves in spring, it'll get worse.
People should think carefully where they intend to install solar panels, before putting them in, else they will be buying an investment that will underperform its optimum.
If shading is an issue, I would have installed the panels on Solar Edge Inverters, with 1 microinverter per panel.

 

[babba]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Mad to think 12 months ago you would be looking at that kind of money for 4KW...You will be able to pick a pv system at the 99p shop soon..only messing...greg..now go back to bed...

 

[Mark42]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

I notice that there seems to be some shading in the photos, how where you thinking of creating fair test conditions? cut down the trees or swap the panels from one side to the other after a year? even the early morning late evening shadows could affect the results significantly!

Good question. There is young woodland South of the shed. I intend to pollard the trees that are close to the building this week, and keep the tops of the trees below the gutterline.

The tree density is equal on East and West so I expect both sides of the total array will be equally disadvantaged, as you say, in early morning and late evening.

It's good that there is a little shading, since performance under partially shaded conditions is an important design characteristic of PV panels, so should be included in the test.

 

[Mark42]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Certainly is a very exciting experiment you have going there. May be open a straw poll …

Hi Mark. Thanks for the support.

I like the idea of a straw poll. Especially if there’s a quid on it

Maybe a dinner at a local pub in a year’s time, a nail-biting revealing of the results, and the ‘losers’ (who backed the wrong panel) paying the bar bill?

Cheers

Mark

 

[Earthstore]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

I can be a little harsh with some posters on here, but cash and dash is doing an experiment here, that all of us can learn from, as I see it, he has no personal gain from this and has funded it from his own pocket.
So be constructive, but support the guy, don't have a go at him.

Thanks

 

[Vegelen]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

It's good that there is a little shading, since performance under partially shaded conditions is an important design characteristic of PV panels, so should be included in the test.

Solar Panels love shade as much as a blind man loves not seeing the light.

 

[Markc]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Hi Mark. Thanks for the support.

I like the idea of a straw poll. Especially if there’s a quid on it

Maybe a dinner at a local pub in a year’s time, a nail-biting revealing of the results, and the ‘losers’ (who backed the wrong panel) paying the bar bill?

Cheers

Mark

Now you're talking my language.

 

[Mark42]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Q/ Why do people put expensive solar pv panels in poor locations, surrounded by trees with lots of shade potential?
A/ They act before they think.
To add insult to injury, they then install them with inverters not preferentially designed to work well in shady conditions. …

Really?

Well, a salesman told me that when you have potentially shaded conditions, you MUST buy the most expensive panels because they are designed to deal with the shade.

But I don’t care.

Because this is a real-world test, based on a real install, not a lot of unsubstantiated hearsay, or pushing of suppliers’ preferred systems.

Shaded or unshaded? Sahara desert or Norfolk? North or South or East or West? So what?

Here are two sets of massively-differently priced panels in a real location side-by-side. I’m not sure it’s been done before. Why not?

I’m expecting the ‘losing’ panel’s supporters to come up with all kinds or ‘Ah buts…’

eg ‘This is slightly shaded but ‘my’ panel would have been so much better in full sun.’ or vice-versa. Sorry, it’s all BS.

If anyone disagrees I suggest you also try an experiment so we can compare.

What’s the expression? Put your money where your mouth is?

 

[Markc]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Come in guys we've all seen far worse on here than this. As by reading later posts the trees will be pollarded (is this a word?) and shade will then be minimal. Anyone who thinks they can install with zero shade is diludded IMO anyway. Minimal shade here and not a bad installation at all. Very well thought out. And in REAL life conditions.

 

[FB.]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

I would expect, at recent prices (before the current panic buying) a 4kWp Sanyo-panel system to retail for around £12.5k and an equivalent Cheap Chinese-panel system to retail for around £9k. With the recent panic buying, prices may be 10% higher if you can actually find anywhere with stock of the make/model which you really want.
Prices assume that the only difference is the panels.
Other perceived levels of quality sitting somewhere between the two extremes.

 

[SRE]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

What's the definition of the winner? The one that generates more in comparison to it's prediction or the most cost effective?

 

[Mark42]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Such comparitive [sic] tests between 2 different solar panels are best done in installation locations with minimal shading issues to get a fairer test result.

Why?

You mean in the Sahara desert for example?

Clouds produce moving shade just as much as a tree branch. The UK has clouds sometimes.

A occasionally slightly shaded location is ideal for a real-world test.

 

[FB.]

Re: PV Panel War: Sanyo v. Hengji. The ultimate side-by-side long-term, real-world t

Really?

Well, a salesman told me that when you have potentially shaded conditions, you MUST buy the most expensive panels because they are designed to deal with the shade.

The recent snowfall gave me a chance to monitor the performance of my two strings of (cheap-ish) panels while some panels were covered (or part covered) by snow.

My conclusion was that a single panel which was covered by snow simply allowed its bypass dioides to channel the power around it, with a negligible loss of output to the others in the string, or to the rows of its own cells which weren't shaded.
One panel out of eight shaded seemed to result in only a fraction less than what I would have expected from the remaining seven panels.

However, diagonal shading across panels is very bad as the cells are arranged in lines (with bypass diodes often at the ends of each line). So if one cell in each line is shaded by a diagonal shadow, the whole panel is basically shut down. If the shadow - such as a telephone pole - extends diagonally across several panels, it shuts all shaded panels down. Any panel in the string which remains unshaded will continue to function normally. Clever orientation of the panels (landscape v portrait) could reduce the effect of shading by reducing the number of panels (or rows on a panel) in shade at any given time.