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

[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.

 

[Mark42]

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 its prediction or the most cost effective?

Good question.

I’m not in the slightest interested in predictions, only in results.

The ‘winner’ (if any) will be the panels which demonstrate a statistically-significant economic advantage, taking into account the whole-life cost of ownership. That’s why I need base retail costs.

I think a fair period on which to judge the result would be to use ten years as a basis for the calculations, extrapolating from one year’s data. My partner is a mathematician by training, so I’ll leave that stuff to her: statistical analysis is a black and unknown art to me.

 

[SRE]

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

Our telephone wire runs diagonally across our array (issues with BT moving it) we produced 15% more than PVGIS and PVSOL suggested we should over a year. The wire is approx 250mm from the panels at one end and 400mm at the other. I'd expected lower than anticipated generation particularly as we have Sharp panels but I can't really complain about the impact shanding has had.

 

[Mark42]

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

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.

Thanks, FB, for your intelligent analysis. All most interesting!

 

[whinmoor]

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

Interesting experiment. Looking forward to following progress. Could you provide links to the datasheets for the panels and inverter? Serious gamblers like to study form before putting down their hard earned cash ;-)
A few questions:

a) Could you tell us (roughly) where in the country this is happening?
b) What's the pitch of the roof? It looks pretty shallow to me - maybe only 20-25 degrees?
c) Will you intervene in any circumstances? Any cleaning planned? What if a flock of birds from the nearby trees mess all over one end of the array? Is it just tough?

 

[SRE]

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

I think a fair period on which to judge the result would be to use ten years as a basis for the calculations, extrapolating from one year’s data.

Mmm for someone not interested in predictions I can't quite see how an extrapolation from one year's data can be accurate - how do you know what the ongoing rate of degradation will be. Maybe HJ panels will degrade quickly in year one but have minimal degradation from 2 - 10 years.

My money's on HJ by the way ..... not scientific in any way ;-) I've just got other things to spend my cash on than top of the range branded panels.

 

[FB.]

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

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.

I was also trained as a scientist, so don't think I'm being awkward when I suggest that perhaps your local climate tends to have more sun at certain times of the day, so perhaps one of your systems will be slightly advantaged. Also the panels will prefer to be running cooler, so those with afternoon sun may have a small loss of efficiency due to the temperature usually peaking around 2.30pm (well, that's typical for when it peaks here).
I'm in East Anglia and both my "gut feeling" and local weather station data/observations suggest that my local area gets slightly more sun (and slightly stronger sun) in the mornings, whereas lunchtimes often cloud-over and afternoons often have hazier sunshine.

 

[FB.]

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

b) What's the pitch of the roof? It looks pretty shallow to me - maybe only 20-25 degrees?

That could put the quality of the panel's self-cleaning coating under test. The repellent coating alone might be a major performance factor unless the panels get a periodic cleaning (but on a realistic timespan).

 

[Mark42]

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

Interesting experiment. Looking forward to following progress. Could you provide links to the datasheets for the panels and inverter? Serious gamblers like to study form before putting down their hard earned cash ;-)
A few questions:

a) Could you tell us (roughly) where in the country this is happening?
b) What's the pitch of the roof? It looks pretty shallow to me - maybe only 20-25 degrees?
c) Will you intervene in any circumstances? Any cleaning planned? What if a flock of birds from the nearby trees mess all over one end of the array? Is it just tough?

I’ll get links to the form sheets in the morning – going to bed soon

1. It's no secret: North of Diss in Norfolk. Approx N 52° 27’ E 001° 08’
2. Yes, it’s shallow. 15 degrees. Sub-optimal, but all panels equally disadvantaged.

1. In that scenario, I would clean the birds' mess off. Unless of course it was equally spread over both sets of panels, when it would be a difficult call

 

[Vegelen]

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.

What are salesman there to do? Sell

Don't always believe what they tell you.

I am currently monitoring 2 systems: Suntech v Sanyo Hits

Suntech monocrystaline panels are outperforming Sanyo Hits in low light conditions by 10-15%, but underperfoming significantly in bright conditions (40%).

The latter conditions are when you preferentially want solar panels to outperform in preference to the former, but the ideal panel would ideally be good at both, which most panels are not.

 

[Mark42]

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

I was also trained as a scientist, so don't think I'm being awkward when I suggest that perhaps your local climate tends to have more sun at certain times of the day, so perhaps one of your systems will be slightly advantaged. Also the panels will prefer to be running cooler, so those with afternoon sun may have a small loss of efficiency due to the temperature usually peaking around 2.30pm (well, that's typical for when it peaks here).
I'm in East Anglia and both my "gut feeling" and local weather station data/observations suggest that my local area gets slightly more sun (and slightly stronger sun) in the mornings, whereas lunchtimes often cloud-over and afternoons often have hazier sunshine.

Bloody scientists: they always need to pick holes in each other’s hypotheses and experiments.

I love it!

That’s the way to discover the true reality behind false perceptions, and it’s what science and the search for truth is all about.

What you say is true: my experiment only applies within my local climatic conditions.

A more perfect experiment would be to repeat the exact-same set up in many different UK locations. But unfortunately my research budget does not run to that.

Perfection, as one so often finds in life, is an elusive phenomenon.

ps. I too have a gut feeling about this experiment, but I try not to think with my gut.