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diy solar

diy solar

average solar panels for very cheap price or the super efficient ones for triple the price per watt?

rockwind1

Natural selection intervention specialist
Joined
Nov 19, 2020
Messages
85
Location
Az
obviously the low light production of the bifacials or high end panels is much better,, but they are way bigger and heavier for a diy project. meanwhile, a few extra cheaper panels are a 1/3 the cost. hmmmmm
 
True, but you also have to compare the degradation of the panel output over time. For example an REC Alpha panel is designed to retain 92% at year 25. Spec sheet lists this as 0.25% annual degradation. Lower cost panels can loose power at twice that rate or more.

This is why Price and Value are not the same.
 
True, but you also have to compare the degradation of the panel output over time. For example an REC Alpha panel is designed to retain 92% at year 25. Spec sheet lists this as 0.25% annual degradation. Lower cost panels can loose power at twice that rate or more.

This is why Price and Value are not the same.
Even at twice that rate of degradation, it would still be well above 80% production at year 25. For 1/3 the price, it's hard to argue the economy of the cheaper panels. Replace them entirely at the end of 25 years, and do it again in another 25 for the same price as the triple-priced panels...then do the math. Hmmm....75 years for the price of ? years?

To my mind, it's hard to rationalize why one piece of silicon would degrade much faster than another. Silicon is silicon, and solar radiation is solar radiation. The primary distinction between panels must be in their coatings...so if one becomes more opaque over time than another, that could account for the difference in productivity.
 
obviously the low light production of the bifacials or high end panels is much better,, but they are way bigger and heavier for a diy project. meanwhile, a few extra cheaper panels are a 1/3 the cost. hmmmmm
I think some people require the more efficient panels due to space limitations. They require a certain level of production, but have minimal space for it, thus necessitating a larger budget for the superior panels. If one has no space limitations, the pricier panels make less economic sense. There are also some people who just want the best of everything, and have the budget to get it--for them, economy is not a concern.
 
If you roof has to be changed out every 15 years or sooner to keep your insurance would you put the old panels up on a new roof?
 
I find the cost of installation is significant, not just the cost of the panels, but cost of racking, wire connectors etc.
For my installations, 400-550 watt panels = fewer connections,less wire, fewer panels to install; compared with 2x as many cheaper 200-250W panels.
It may be best to compare "all in cost" of arrays, ie total cost of - panels + racking + wire + connectors.

If you have roof mounted PV you may also need a Tigo for each panel = fewer large Wattage panels is fewer Tigo's
 
It really depends on physics as much as cost in my book. If you have acreage of south facing hillside on the plains, why pay the extra to save you 10 panels in your 100 panel array?

On the other hand, when you're trying to maximize space on your RV or your cabin in the woods, lots of cheap panels just don't fit and paying extra to get every last watt out becomes value.

Short answer? It depends...
 
I bought 200w cheap panels because they were on sale as I was supposed to be building a fun little project...... 2 months later I found better panels, cheaper at regular price.
So I think it also depends on your status in the universe. (I am also 95% guaranteed to be in the slowest checkout line at the store. My status is not very high)
 
obviously the low light production of the bifacials or high end panels is much better,, but they are way bigger and heavier for a diy project. meanwhile, a few extra cheaper panels are a 1/3 the cost. hmmmmm
Price per watt tends to favor the large panels. The amount of efficiency has reduced the size somewhat but the difference among most new panels is marginal when you are talking 20 =>23% efficiency. 1sqm being 200W versus 230W I would be suspicious of a 1/3 price difference as possibly being a false wattage representation.

Bifacials have additional real estate to work with and recently their price has been very reasonable even cheaper than standard panels.

Worse issue I have found for those of us off the beaten path is you can buy the smaller panels such as RV panels individually with free shipping but the larger panels you most often have to buy a pallet load with extremely expensive truck shipping. If you live where you can go pick up the panels yourself that issue goes away or sometimes the price of a pallet with shipping is still good enough to keep the watt price low.
 
I have loads of space, so buy based on Watts per £, if I was short on space then I would buy on efficiency.
 
obviously the low light production of the bifacials or high end panels is much better,, but they are way bigger and heavier for a diy project. meanwhile, a few extra cheaper panels are a 1/3 the cost. hmmmmm
But is it really better? It's a marketing game.

EG: ~30% more efficient at low light conditions doesn't mean much since the panels, regardless of technology, are producing less than 5% of thier rated output.
 
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Someone here on fb market place is selling 20 x 100w panels for $25 each.... I wonder if they realize how overpriced they are for 12 year old panels?
 
obviously the low light production of the bifacials or high end panels is much better,, but they are way bigger and heavier for a diy project. meanwhile, a few extra cheaper panels are a 1/3 the cost. hmmmmm
It's usually cost/W which matters most, but as already said you need to think racking, wiring, Voc vs inverter, available room, local weather, roof vs ground installation too. Panels are usually the cheap part, so savings aren't that big there.

Here in Finland I can get top of the line Bluesun bifacials (23,2% efficiency, N-type) around 0,17e/W including VAT 25,5% and home delivery so looking for cheaper panels is not worth my time. These are 650W and huge in size, but I already have their older 700W bifacials (22,8%, N-type), so I don't mind dealing with bigger panels. For my roof installation I went with P-type monofacials as I sourced them locally with similar price but didn't have to wait 2-5 months for delivery. For ground installation I'd go bifacial every time.
 
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My racking is going to cost around $100 per panel because of the wind and snow load.

Base of $200 + $100 per panel after the first one.
 

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