Pros and Cons of "premium" solar panels?

sidpost

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I'm new here but, not new to solar. I have been using a Midnite Solar KIDD charge controller to do things like put heat in electric water elements (keep fish warm overwinter in tanks) and the more classic charge batteries and use an inverter to run things.

I'm shopping for pallets of panels so my options are somewhat restricted due to availability. What I am trying to understand is what I get with premium names like Panasonic, LG, Kyocera, and others that I don't get with less familiar names from primarily China.

I get cosmetics for home roof installations, consumer name recognition, and generally top technical specifications. However, at ~$1/watt they are pretty spendy and I don't need the higher efficiency per square foot they offer over less efficient but equal watt panels.

I am in Texas so, heat effects are a consideration (thermal curves). Physical things like wind loading and hail seem to be well within industry norms so, no advantage or disadvantage there. Efficiency at 10, 20, or 30 years is something that is very hard to figure out from the information I have access to right now.

Then there is the price premium (apparently) for 144 cell 1/2 panels. Shading out or losing 1/2 a panel is certainly better than losing a whole panel but, I'm not convinced that is something with a lot of value for myself as I won't be installing them near trees, and dirt or grass debris won't be issues encountered very frequently, if at all.

I'm looking for ~10Kw per pallet so, given a little power loss for various reasons puts me in the 370W~400W range per panel. My other thought is simply to buy the Poly panel that is cheapest per Watt and just buy more of them but, that isn't a linear savings since mounting and placement costs will be higher for a larger panel count of less wattage (everything from mounting brackets to wire costs, etc.).

So, where is the "sweet spot" or range in solar panels today for someone like myself?

For a starting point of discussion, I'm looking at the Hyundai HiAS360HI 144 Cell Monocrystalline Solar Panel which runs $160 plus shipping.

TIA,
Sid
 

Hedges

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There are differences in quality, failure rate, production degradation over time. Various reports highlight failures observed, but they usually don't name bad ones, only good ones.

Look at used/surplus, for instance at SanTan Solar. Many of us have bought from them.

Panels are getting low enough in cost that mounting hardware and labor is starting to dominate. So buying cheapest may not save all that much. I'd say get a brand with reputation and track record.

The various clever layouts may work for specific situations. A panel consisting of two parallel strings of half panels, if connected series with other panels and partially shaded, would either knock out half the other panels current, or they would reverse bias it and all of its output would be lost. Typical panel with 2 or 3 diodes would only lose the shaded portion.
 

sidpost

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There are differences in quality, failure rate, production degradation over time. Various reports highlight failures observed, but they usually don't name bad ones, only good ones.

Look at used/surplus, for instance at SanTan Solar. Many of us have bought from them.

Panels are getting low enough in cost that mounting hardware and labor is starting to dominate. So buying cheapest may not save all that much. I'd say get a brand with reputation and track record.

The various clever layouts may work for specific situations. A panel consisting of two parallel strings of half panels, if connected series with other panels and partially shaded, would either knock out half the other panels current, or they would reverse bias it and all of its output would be lost. Typical panel with 2 or 3 diodes would only lose the shaded portion.

Thanks! One thing I like about the Hyundai panels is that they have the diodes to prevent the reverse bias. Hyundai is a recognized name so, I guess I'm good there.

Failure rate and production degradation are two issues that are not easily found. I suspect this is partly due to technology changing so fast relative to the service lives of the solar panels.
 

HRTKD

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Since you're in Texas, consider Mission Solar, which is based in San Antonio. Unfortunately, their website appears to be FUBAR at this time. I hope they are still in business.

Mission Solar is a subsidiary of OCI Enterprises, Inc, which in turn is a subsidiary of OCI Company Ltd, a South Korean company.
 

Hedges

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Here's a post with link to reports you can download on accelerated tests. It names names only for "Top Performers" in each category.
I don't find Hyundai in the 2020 report, didn't check the others.

SanTan has some new panels with full manufacturer's warranty, including REC and Seraphim (about $0.50/watt) which are included in the "Top Performers" list for some years.


Looks like they have a small quantity of the 370W Hyundai panels remaining:

So you found the Hyundai at SanTan? Contact him with the quantity you want and he'll probably give a discounted price.
I don't see warranty mentioned in the posting, but you can ask if it is provided by manufacturer.
I had shipping to a freight terminal rather than home for lower shipping cost, and they forklifted pallets into my pickup truck.


Diodes matter when some panels in a series string are partially shaded, so current from others in the string can push past them. For some brands, having partial shading when others are in full sun is said to be improper use, and the diodes aren't heatsinked well enough to take the current, will burn up.
Some panel designs have a layout meant to tolerate a shadow on the edge of all panels, like a commercial ground-mount array with one row partially shading the next. I avoided that for home use, because my shadows are from trees.

Double-check the voltage and current calculations for your inverter or SCC before ordering, make sure that fits and you can connect the right number of series strings. Since shipping costs more than a panel, you might order an extra in case you break one.
 

sidpost

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Thanks! Yes, SanTan is the primary vendor I have been in contact with.

They don't have many Seraphim panels in stock except for the singles you see on their website. Same for the Hyundai panels as well. They have very few options in pallet quantities.
 

jwelter99

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Also check out Northern Arizona Wind and Solar as they often have some good deals. I saw Rec panels for a pretty good price a couple weeks ago listed.
 

Hedges

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I think the new panels are leftovers from installs, which would explain limited quantities. Sometimes they have used panels from solar farms, so thousands. I've seen ads on eBay from other vendors as well. One vendor had panels from a solar farm he said experienced a grass fire, which damaged some panels. The undamaged panels were being sold by the pallet, not very old.
 

tanoshimini

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I paid ~$135/ea (incl. shipping) for two pallets of Hyundai HiAS370HI panels, 54 in total. I bought them off a seller on ebay, no troubles, beautiful panels. I had a little problem with the shipping company (UPS freight), who misrouted the panels, but once that was sorted out...
 

Hedges

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Gift horse and all that? It says the shipping was free :ROFLMAO:

I've received truck shipment from UPS, Fed Ex, Estes, CST.
Generally works out fine. Biggest hassle has been when a shipper specified "direct signature required", which prevented me from requesting a hold at the terminal. Had to wait for failed delivery, then sender could make the request. For truck shipments I request hold at terminal in advance.

I see a similar but not identical panel series from Hyundai listed in the following report.
It is a top performer for some tests, but not "PID" which I'm learning about. "Potential Induced Degradation"
Apparently P-type silicon cells hold up better if negative terminal is grounded. N-type hold up better if positive grounded.
Some panels are more resistant to the damage than others.
An un-grounded PV array like for a transformerless inverter will have half the panels at the less-ideal bias relative to ground.

See if you can figure out which type of cells these are, and try to use them in the less harmful configuration.



I've been running SunPower, AstroPower, and Sharp panels all on a transformerless inverter for a year.
I'm migrating the SunPower to a positive grounded inverter, the others to negative grounded (like they were for the previous years.)
 

tanoshimini

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Gift horse and all that? It says the shipping was free :ROFLMAO:
I know, right? ;)

I see a similar but not identical panel series from Hyundai listed in the following report.
It is a top performer for some tests, but not "PID" which I'm learning about. "Potential Induced Degradation"
Apparently P-type silicon cells hold up better if negative terminal is grounded. N-type hold up better if positive grounded.
Some panels are more resistant to the damage than others.
An un-grounded PV array like for a transformerless inverter will have half the panels at the less-ideal bias relative to ground.
Interesting... I’ll be running these with enphase microinverters, so I wonder if that negates the issue to a degree?

See if you can figure out which type of cells these are, and try to use them in the less harmful configuration.

This is a dead link for me. :(
 

Hedges

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Try the links given here. I had registered (free) to access, then Snoobler provided a link to .pdf


Yes, floating on an Enphase, maybe half the panel will be above vs. below ground by Vmp/2, not very much. Not nearly as bad as + or - 600V to 1000V.

My new inverters (ca. 2011) have a GFCI fuse that can provide either positive or negative grounding, makes it easy.
But I can't mix strings of different types while using bias polarity to completely eliminate the issue.

Apparently more of a problem at higher temperatures, maybe humidity, some encapsulation materials more than others, also voltage.

I wish the reports put names and numbers together, including poor performers. Maybe if I was a paying customer? (There's that gift horse, again.)

Speaking of "gift horses", our govt. got the bright idea of paying people to take horses (because we have too many wild & free ones.) As soon as they receive "title", you know what happens. More profitable than running livestock, they said.
 
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