Are all panels basically the same now?

[TedM]

I'm looking at two different panels - both 500w and both about £80/panel with free delivery.  Is there likely to me any real difference between them?

(One is the LONGi Hi-MO X6 and isn't in stock, the other is a DMEGC and is in stock)

[Nickfromwales]

20 minutes ago, TedM said:

I'm looking at two different panels - both 500w and both about £80/panel with free delivery.  Is there likely to me any real difference between them?

(One is the LONGi Hi-MO X6 and isn't in stock, the other is a DMEGC and is in stock)

I’d buy glass / glass vs glass / foil, as these have much better longevity. 

[JohnMo]

1 hour ago, TedM said:

DMEGC

 

1 hour ago, Nickfromwales said:

glass / glass

If you are getting the bifocal version they are glass / glass. Also watch as I found the datasheet and actual panel size where different, datasheet saying they were bigger (long side) than actually size.

[Nickfromwales]

17 minutes ago, JohnMo said:

 

If you are getting the bifocal version they are glass / glass. Also watch as I found the datasheet and actual panel size where different, datasheet saying they were bigger (long side) than actually size.

If going in trays this is of vital importance. If on a rail system, not so much, but a very good point!

[SteamyTea]

If the panels are going on a roof, how does the bifacial part work?

[Nickfromwales]

1 hour ago, SteamyTea said:

If the panels are going on a roof, how does the bifacial part work?

It doesn’t. You just discount it. 

[SteamyTea]

30 minutes ago, Nickfromwales said:

It doesn’t. You just discount it. 

Be cheaper to buy non bifocal ones then.

[Nickfromwales]

12 minutes ago, SteamyTea said:

Be cheaper to buy non bifocal ones then.

Maybe cheaper, but not by much, to have a glass / foil panel with far less longevity. 

[Mr Blobby]

4 hours ago, TedM said:

I'm looking at two different panels - both 500w and both about £80/panel with free delivery.  Is there likely to me any real difference between them?

(One is the LONGi Hi-MO X6 and isn't in stock, the other is a DMEGC and is in stock)

 

Not all panels are the same.  Two differences I think, colour and size.

Some are all-black, and some have the wires showing.  The latter are cheaper.  AFAICS the panels you are looking at have the visible wires.  Then, in the all-black category, some, such as JA solar are emarketed as all black but up close you can see the wires.  The other, like the N type, from AIKO are all black with no visible wires.  Which I think look awesome, if that's relevant to you, and also not too expensive.

 

In terms of size, 1750 is traditional size.  500W panels tend to be bigger at 1950, but the power per area is not really any better.

 

39 minutes ago, SteamyTea said:

Be cheaper to buy non bifocal ones then.

 

Yes, I never understood how having cells on the underside of the panels to ostensibly acheive a higher power rating was anything but a scam.  

 

Edited Thursday at 15:20 by Mr Blobby

[Nickfromwales]

35 minutes ago, Mr Blobby said:

Yes, I never understood how having cells on the underside of the panels and giving a higher rating was anything but a scam.  

I think the cells are bi directional, so when you go glass / glass you inherit some degree of uplift if irradiance is bounced off something and hits the back / underside of the panels, and afaik there aren’t any panels / manufacturers where anyone would purposefully place cells on the rear.

 

You still get salespeople telling folk that light reflected by the moon can add to generation…….all of these idiots are dynamite lovers with a 2” fuse lol.

[JohnMo]

26 minutes ago, Nickfromwales said:

You still get salespeople telling folk that light reflected by the moon can add to generation

Maybe not - panel may generate something, but not enough to trigger anything to work like your inverter.

[Nickfromwales]

6 hours ago, JohnMo said:

Maybe not - panel may generate something, but not enough to trigger anything to work like your inverter.

We may need to conduct Buildhub's first ever exorcism.......... 

[sgt_woulds]

I don't know where this fear of foil backed panels comes from.  As long as you buy tier 1 panels (the most important thing when buying any solar panel), and don't mount them upside down (to collect the reflected light? 🙂) then there isn't much that will damage them.

 

I have a foil backed panel from 1982 mounted to my shed that is still perfectly fine and still producing its rated output.

 

But to answer the OP question, no they are not all the same.  You need to look for vertically integrated (tier 1) manufacturers, who make their own cells and assemble the panels themselves.    e.g. Tier 1 Solar Panels List 2025: Updated Manufacturers & Rankings – RENVU

 

Although I imagine it is rare now, I remember installing an early batch of no-name chinese panels that were so poorly made that the cells moved around behind the glass as we installed them.

[TedM]

Ahhh, OK so DMEGC should be OK.

 

Are >500w [bifacial] panels actually better than 460w panels or are they just fudging the numbers from some potential generation from the rear?

 

In other words, spend slightly more on bifacial 500w panels or less on 460w panels?

[JohnMo]

Just now, TedM said:

Ahhh, OK so DMEGC should be OK.

 

Are >500w [bifacial] panels actually better than 460w panels or are they just fudging the numbers from some potential generation from the rear?

 

In other words, spend slightly more on bifacial 500w panels or less on 460w panels?

I have 500W (x2) and 460W (x12), suspect they travel down the same production line, get a test at the end and go in either one of several piles, depending on actual measured output.

 

Production from the panels is good. Seem nice solid ,well made panels.

 

Prices are going up daily, so do don't hang about in procrastination mode 

[Nickfromwales]

1 hour ago, sgt_woulds said:

I don't know where this fear of foil backed panels comes from.  As long as you buy tier 1 panels (the most important thing when buying any solar panel), and don't mount them upside down (to collect the reflected light? 🙂) then there isn't much that will damage them.

 

I have a foil backed panel from 1982 mounted to my shed that is still perfectly fine and still producing its rated output.

 

But to answer the OP question, no they are not all the same.  You need to look for vertically integrated (tier 1) manufacturers, who make their own cells and assemble the panels themselves.    e.g. Tier 1 Solar Panels List 2025: Updated Manufacturers & Rankings – RENVU

 

Although I imagine it is rare now, I remember installing an early batch of no-name chinese panels that were so poorly made that the cells moved around behind the glass as we installed them.

It’s not fear, it’s fact-based industry feedback that drives my comments. The foils micro-fracture over time, and that starts the process of degradation. Solarwatt stated (iirc) <0.5% degradation per annum and that was on the cell itself, as the cell and its connecting metals are hermetically sealed; this is largely the job of the foil in a glass / foil panel. 
 

Your 1982 panel is quite rare, I’d say nearly unique! Defo not a Friday panel if it’s suffered zero degradation in over 40 years. 

[sgt_woulds]

Its an ARCO panel.  Pre-production / hand assembled.  A real chunky monkey for back in the day - 42w!   Still putting out 16+volts.

 

I guess the modern foil quality has dropped, or, more likely, the larger panel sizes flex more and put more stress on all componants. 

 

The old 980x1650 formats with chunky frames, thick glass, and long-edge only clamping zones probably will last longer.

[SteamyTea]

Going to be equinox in about 50 minutes, more time to generate PV.

[TedM]

6 hours ago, JohnMo said:

Prices are going up daily, so do don't hang about in procrastination mode 

I was wondering about that and, as I am a fantastic procrastinator, I've gone and bought 5 x DMEGC All Black 515W Bifacial panels from PlumbNation as City Plumbing are out of stock of what id like and can afford.

The only downside I can see is that delivery takes 8 days ☹️

 

But I guess that gives me some time to run the cables as they need to go in/under the concrete yard base.

Edited Friday at 16:17 by TedM

[Alan Ambrose]

Guess I have to ask - why would panel prices be going up?

[BotusBuild]

Energy and transport cost increase being passed on?

[JohnMo]

59 minutes ago, Alan Ambrose said:

Guess I have to ask - why would panel prices be going up?

Maybe watch the news. Everything else is going up, looked earlier in the week, the panels I bought were £76 including vat, today £88, when I bought £67 and the prices dropped the next day.

[TedM]

On 20/03/2026 at 16:55, Alan Ambrose said:

Guess I have to ask - why would panel prices be going up?

A number of reasons I guess - but it seems the prices have already gone up since last week.  The panels I bought from Plumbnation at £82/each are now £92 at CityPlumbing!

[joth]

On 20/03/2026 at 17:57, BotusBuild said:

Energy and transport cost increase being passed on?

That and people panic buying PV because energy prices are going up. (Same way as SUV sales make a distinct drop whenever fuel prices increase).

Plus today's news that balcony solar will be legalised in the UK is only going to add to the short term spike in demand here.

 

[-rick-]

Also, the overbuild of supply from China is likely mostly resolved now and the Chinese government have stepped in to regulate the market there to limit overproduction. The £50 a panel price we saw a year or two ago was because a significant number of factories all came online at the same time and the market couldn't absorb the supply.