We will try and work out a practical test, there’s a lot of demand for that -especially to measure the bifacial side. I’m a big fan of your channel and would love to collaborate with you. Thanks for the comment! -Tok
I'm glad @UpsideDownFork has seen this given his recent video. I've commented on quite a few of Heatables videos that the they are installing bifacial panels which are not going to result in any meaningful gain. They are designed for ground mount, car ports or perhaps a solar fence where the rear side can get a good amount of reflected light. Heatables said they will run a side by side comparison months ago, but I've never seen it. Basically they just want to keep it simple for themselves, advertise a product as premium and therefore worth paying extra for, and to lead people to believe they are getting a better performing system, when for most people they won't be.
Hi I liked your video, made me rethink my ideas on bifacial panels, I think the real question for us in UK is we need a panel to start working in lower light and continue to work through out the day, even on very cloudy days and summer peak is less important than what the same panels will do in December.
Thanks for your comment. These REA panels do claim to have superior low light generation, but I’ve not seen proof. I agree a certified low light panel would be brilliant! -Tok
@@spiritenergy_ukI've never really understood the efficiency aspect of panels. A 30% efficient 400w panel can do 400w's A 21% 400w panel can do 400w's. What am I missing or have misunderstood?
Thank you for the comparison review. I was just thinking on the same lines as you tbh so nice to get your opinion in detail. Too quality TH-cam channel And solar company keep up the good work .
There's a lot of marketing hype out there, with precious little in the way of transparency or impartial test data. Any video that can help shed light on the supposed merits of new technology is always welcome, so please continue to look into these.
One thing that never makes these videos is the bypass diode configurations. I understand half-module bypasses are fairly common, I'd be interested if any are more subdivided than this and whether this further mitigates the partial shading question.
Brilliant point. Video coming soon. See this video where we talk in detail about how we take that into account for system design…. th-cam.com/video/zLFvUKHETrQ/w-d-xo.htmlsi=eOpYCoXA6vrDe8I6
Heatable talk a lot about the low light performance of the Fusion2 cells compared to others - is this just related to them being n-type, or is there more to it? I looked in the PV*Sol database, hoping to find the low light performance curves, but there wasn't an entry for them.
They say it’s to do with the triple wafer design of the panel. The microinverter will also help a bit as it’s got a low minimum input voltage. Whether it makes a notable difference to annual generation is another question.
Check out Hoymiles microinverters. Some of them can have up to 6 panels connected, ideal for real small systems. And they can actually pull decent of amounts of power from modern panels. Unlike Enphase which seems stuck to the panel standard from 3 -4 years ago.
I've been wondering about bi-facial panels combined with solar reflective paint. There are several products that almost perfectly reflect a huge number of wavelengths of light to the point were the underlying roof is kept cooler than ambient temperatures. I'm not sure if solar/heat reflective paint would have a detrimental double heating effect on bifacial panels as they are warmed from both sides, or if they would just get a boost from the additional reflected light.
@@spiritenergy_uk Mounting solar panels closer to the asphalt surface may lead to a minimal contribution from albedo effect. Could this potentially affect the energy production from the panel's rear side? In the UK, does solar cells have chamfers on the corners?
It may be worth noting that even though the REA/Enphase micro system is clipping at 380w limiting even the basic 440w peak pannel output in summer, this system may be a different scenario in the winter months. This is what I want to find out. Double sided glass also seems beneficial in bifacial arays
This is correct. Over the course of the year microinverters tend to increase generation by 1-2%. Which isn’t enough to pay for themselves but they do help. -Tok
I like double-sided glass panels too, lower degradation, and an improved temperature curve, but there are far cheaper glass/glass panels on the market. JA Solar's Deep Blue 4.0s are very common in the market, are well priced, and also glass/glass. I'm hoping that Aiko will bring their glass/glass back-contact panels to the UK market when the third generation arrives (their second generation glass/glass panels seem to be common in the EU but the UK Aikos only have glass on the front).
@@WyndStryke I may get a single deep blue for a little balcony solar project I have in mind and I am currently researching. Going to look a little odd on a single door width juliet balcony but I can potentially fit a second as an awning/canopy above the front door, teamed up with an ecoflow microinverter as a "balcony solar" or "plug in solar" solution. Not sure yet, not had a chance to look into the voc limitations on that panel. the ecoflow can handle 2 400w panels (2x400 mppts, so cant combine for a single panel over 400w) a very interesting little system for anyone on shared ownership whos housing association is being a dick and not allowing them to fit big boy solar until they own the full 100% of the property :D
Bifacial might give you 1-2% on a roof. To get more you need them on an elevated ground mount with a reflective surface underneath and behind them. Of course with the microinverters you'll never see the maximum output as it's limited to the microinverter output.
The Neostar 2 makes claims on superior shade mitigation performance compared to other standard panels. Is this just unsubstantiated marketing, or are there physical differences that explain how these claims are achieved please? I’m getting these panels but can’t find anything to back up the marketing.
Genuine, I believe it is a side-effect of them being n-type back contact cells (related to the breakdown characteristics of the cell, which means that current can flow through them with reduced resistance even when shaded, resulting in both improved shading performance and reduced hotspots). Longi are in the process of developing similar back contact cells, and they are reporting very similar behaviour when a cell is shaded. My guess is that in the late-2025/2026 timeframe, you'll be seeing back contact cells appearing in many different panels.
@@WyndStryke Thank you, that’s very helpful. It’s very difficult being a consumer in the solar market, there is so much obvious marketing b/s that seeing the wood from the trees is nearly impossible unless one has a higher degree in micro electronics. If I had a solar install business, I would look to implement a survey process that includes measurement of actual light levels on the intended installation location so that one could provide objective recommendations based upon real data. A measurement device for the particular wavelengths needed on an extendable pole doesn’t seem beyond the wits of man.
The current models work off MCS irradiance data for the postcode. From looking at data from systems that we installed 15 years ago, that seems to be a bit conservative. We will make a video. I do agree there’s a lot of false information going around. That’s why we started this channel. Please do email me for any support. -Tok
@@spiritenergy_uk Thanks. I recoil at the idea of printed circuit boards (even if potted) and additional connections on a damp and cold and inaccessible British roof for 25 years and expecting them not to have failed or partially failed in that time. It’s an expensive repair just waiting to occur, even if replacements parts are available (which must approach zero likelihood). But, at the same time, there is nothing for the consumer to use to see if their specific shading situation requires electronic remediation to work. So in my situation I have a mixture of mature pine and deciduous trees that are 200 ft away so the sun passes either over the crowns or just under and between, depending upon the height of the sun. It is literally impossible for me to know if electronic mitigation is going to give me a 0, 2, 5, 10, 20 or 40% uplift, so when it comes to performing a risk vs benefit analysis I have zero data. It makes it even more complex when there are differing opinions and vested interests involved, the advice ranges from its essential to it will have negligible impact. It looks like you trade predominantly in the Home Counties, but we are in the NW. One question, if you were submitting a G99 for a system that incorporated a powerwall 3. Would you apply for the full 11kW even if the panel output only required 10kW, I would have thought it obvious to apply for the maximum and then negotiate down if the DNO raised objections. I’m a bit pissed with my installer that he didn’t apply for the full capacity as I would have assumed (in case I ever need to add to the system) and that didn’t even discuss with me first. Or am I being unfairly critical?
While this is very interesting theoretically what I would like to see is a test rig (pair of rails?) with different panels fitted and a side by side comparison of what they generate in the real world. Spec sheets are a bit like petrol car MPG or electric car range - subject to a degree of wishful thinking!
Micro-inverters/Optimisers, more expense & more potential failure in the future... Simply put, except for actual damage (golf-ball/hailstone etc...), will a solar panel potentially fail first or an optimiser ??? In vast majority of cases - the optimiser will fail before the solar panel, fit optimisers/micro-inverters to all panels & you will increase the probability of at least one (or more over time) failing. So you will likely have to erect scaffolding, remove a number of panels to gain access to the panel within the array, possibly in the middle than right at the edges, replace faulty optimiser & replace the rest of the panels you removed. (Chances of it being right at edge at fairly slim) This replacement cost, may be carried under warranty, but what time frame before approval to proceed & remedial work completed - for the sake of an optimiser/micro-inverter failing Ahhh - but the safety aspect, auto shutdown etc... Well you've just tripled the MC4 connectors with a Tigo, 2 on panel + 4 on Tigo = 6 MC4's instead of 2 If you replace ends of PV strings with matching Stäubli's, as recommended, then the panel should also be replaced with Stäubli's to match the Tigo's Stäubli MC4's. (Yeah, you could with the compatibility chart, but if so, then you wouldn't need to fit a Stäubli to either of the string on first/last panel as advised - in short, if you fit pairs of Stäubli's at panel ends, then you "should" replace all panel MC4's with Stäubli's, to match the Tigo's Stäubli's) Now you've done all that, everything Stäubli, you still have 6 connectors compared to 2 previously on each panel. No matter how good these Stäubli's are, however snug & watertight they were made, there is still a 3 fold increase in points of potential resistance. 10 panels, you go from 10 x 2 MC4's = 20, to 10 x 6 MC4's = 60 - that's 40 extra MC4 connectors... Admit, these are "connectors" that as a pair make half that as "connections" (So std there are 10 PV connections Vs 30 connections with Tigo'd panels) But no matter what, you've increased/tripled the weakest point in any array/string - the MC4 connector/connection Personally, in an ideal world, if possible avoid them on a roof array, mostly as optimisers will likely fail before the PV panel itself does (excluding actual panel damage from debris/golf-ball/hailstone & no optimiser can prevent that) DC arc prevention - clip cables frequently to keep all cable & especially MC4's off roof tiles & do not let them drape into the rails themselves - especially if using wide channel rail systems like K2. Do not allow the MC4 connector to sit in the channel of rail or drop into the surrounding frame of panel where it could sit in moisture/water. Clip the cable & especially the MC4's well up away from laying on tiles/roof/out of any rail-channel or slip into surrounding frame of panel- any of these areas where water can collect & potentially promote corrosion over time to MC4 Yes, could fit them on a lower install location, shed/garage/carport/angled wall mount - type of place where they could be replaced without needing a full scaffolding erected to gain access... Yes, if a carport/shed had some shading, then I probably would consider optimisers on some/perhaps all panels, but on a main roof of a house - I'd tend not to, or only on a few panels that might require it... I wouldn't kit out all panels on a 2 storey roof, that is just increasing the chance of one optimiser failing before a PV does (Bungalow might be different, as may not need a full scaffold structure erected to remedy any issues) Bi-facial panels - roof isn't going to see a massive potential gain Flat roof/angled wall mount - now you might see a bit more potential gain from a white wall reflecting to the underside, but a black/brown roof tile - maybe not much My own roof is SSE Gable with no shading - hence no optimisers Might put up another modest string on a wall/carport as a sort of solar porch covering, but slight risk of some shading from a neighbour's hedge so I might consider a few Tigo's I have acquired. If they need removal/replacing then it's an easy small ladder task, without needing to call scaffolding company back, but I'm a firm believer in less is more, or don't make things more complicated than need be To each their own, but that is my personal take on it all and the reasoning in my own case/roof/array/system
Very good info. Thanks for the comment! I would agree with pretty much everything. If they can be replaced (safely) with a ladder and the financials make sense then I would certainly go for them myself.
Thanks Tok - a very informative and insightful video on the latest and greatest with solar panel technologies 👍 Easily digestible too!
Thanks Gary!
Great desk analysis. Would love to see a practical test to back up some of the claims.
We will try and work out a practical test, there’s a lot of demand for that -especially to measure the bifacial side.
I’m a big fan of your channel and would love to collaborate with you. Thanks for the comment! -Tok
I'm glad @UpsideDownFork has seen this given his recent video. I've commented on quite a few of Heatables videos that the they are installing bifacial panels which are not going to result in any meaningful gain. They are designed for ground mount, car ports or perhaps a solar fence where the rear side can get a good amount of reflected light. Heatables said they will run a side by side comparison months ago, but I've never seen it. Basically they just want to keep it simple for themselves, advertise a product as premium and therefore worth paying extra for, and to lead people to believe they are getting a better performing system, when for most people they won't be.
Hi I liked your video, made me rethink my ideas on bifacial panels, I think the real question for us in UK is we need a panel to start working in lower light and continue to work through out the day, even on very cloudy days and summer peak is less important than what the same panels will do in December.
Thanks for your comment. These REA panels do claim to have superior low light generation, but I’ve not seen proof. I agree a certified low light panel would be brilliant!
-Tok
@@spiritenergy_ukI've never really understood the efficiency aspect of panels.
A 30% efficient 400w panel can do 400w's
A 21% 400w panel can do 400w's.
What am I missing or have misunderstood?
Helpful comparison
Thank you for the comparison review. I was just thinking on the same lines as you tbh so nice to get your opinion in detail.
Too quality TH-cam channel And solar company keep up the good work .
Thank you!
There's a lot of marketing hype out there, with precious little in the way of transparency or impartial test data. Any video that can help shed light on the supposed merits of new technology is always welcome, so please continue to look into these.
One thing that never makes these videos is the bypass diode configurations. I understand half-module bypasses are fairly common, I'd be interested if any are more subdivided than this and whether this further mitigates the partial shading question.
Brilliant point. Video coming soon. See this video where we talk in detail about how we take that into account for system design….
th-cam.com/video/zLFvUKHETrQ/w-d-xo.htmlsi=eOpYCoXA6vrDe8I6
Heatable talk a lot about the low light performance of the Fusion2 cells compared to others - is this just related to them being n-type, or is there more to it? I looked in the PV*Sol database, hoping to find the low light performance curves, but there wasn't an entry for them.
They say it’s to do with the triple wafer design of the panel. The microinverter will also help a bit as it’s got a low minimum input voltage.
Whether it makes a notable difference to annual generation is another question.
Check out Hoymiles microinverters. Some of them can have up to 6 panels connected, ideal for real small systems. And they can actually pull decent of amounts of power from modern panels. Unlike Enphase which seems stuck to the panel standard from 3 -4 years ago.
I've been wondering about bi-facial panels combined with solar reflective paint. There are several products that almost perfectly reflect a huge number of wavelengths of light to the point were the underlying roof is kept cooler than ambient temperatures.
I'm not sure if solar/heat reflective paint would have a detrimental double heating effect on bifacial panels as they are warmed from both sides, or if they would just get a boost from the additional reflected light.
Doesn't the bi-facial get energized by rays passing through the panel and reflected back to the backside?
Hypothetically but not in reality. See the middle of the video where I talk about this.
@@spiritenergy_uk Mounting solar panels closer to the asphalt surface may lead to a minimal contribution from albedo effect. Could this potentially affect the energy production from the panel's rear side? In the UK, does solar cells have chamfers on the corners?
Great video - How does the Eurener Nexa 500W Bifacial compare?
It may be worth noting that even though the REA/Enphase micro system is clipping at 380w limiting even the basic 440w peak pannel output in summer, this system may be a different scenario in the winter months. This is what I want to find out. Double sided glass also seems beneficial in bifacial arays
This is correct. Over the course of the year microinverters tend to increase generation by 1-2%. Which isn’t enough to pay for themselves but they do help.
-Tok
I like double-sided glass panels too, lower degradation, and an improved temperature curve, but there are far cheaper glass/glass panels on the market. JA Solar's Deep Blue 4.0s are very common in the market, are well priced, and also glass/glass. I'm hoping that Aiko will bring their glass/glass back-contact panels to the UK market when the third generation arrives (their second generation glass/glass panels seem to be common in the EU but the UK Aikos only have glass on the front).
@@WyndStryke I may get a single deep blue for a little balcony solar project I have in mind and I am currently researching. Going to look a little odd on a single door width juliet balcony but I can potentially fit a second as an awning/canopy above the front door, teamed up with an ecoflow microinverter as a "balcony solar" or "plug in solar" solution. Not sure yet, not had a chance to look into the voc limitations on that panel. the ecoflow can handle 2 400w panels (2x400 mppts, so cant combine for a single panel over 400w) a very interesting little system for anyone on shared ownership whos housing association is being a dick and not allowing them to fit big boy solar until they own the full 100% of the property :D
Bifacial might give you 1-2% on a roof. To get more you need them on an elevated ground mount with a reflective surface underneath and behind them. Of course with the microinverters you'll never see the maximum output as it's limited to the microinverter output.
Precisely.
The Neostar 2 makes claims on superior shade mitigation performance compared to other standard panels. Is this just unsubstantiated marketing, or are there physical differences that explain how these claims are achieved please? I’m getting these panels but can’t find anything to back up the marketing.
Genuine, I believe it is a side-effect of them being n-type back contact cells (related to the breakdown characteristics of the cell, which means that current can flow through them with reduced resistance even when shaded, resulting in both improved shading performance and reduced hotspots). Longi are in the process of developing similar back contact cells, and they are reporting very similar behaviour when a cell is shaded. My guess is that in the late-2025/2026 timeframe, you'll be seeing back contact cells appearing in many different panels.
@@WyndStryke Thank you, that’s very helpful.
It’s very difficult being a consumer in the solar market, there is so much obvious marketing b/s that seeing the wood from the trees is nearly impossible unless one has a higher degree in micro electronics.
If I had a solar install business, I would look to implement a survey process that includes measurement of actual light levels on the intended installation location so that one could provide objective recommendations based upon real data. A measurement device for the particular wavelengths needed on an extendable pole doesn’t seem beyond the wits of man.
The current models work off MCS irradiance data for the postcode. From looking at data from systems that we installed 15 years ago, that seems to be a bit conservative. We will make a video.
I do agree there’s a lot of false information going around. That’s why we started this channel.
Please do email me for any support. -Tok
@@spiritenergy_uk Thanks.
I recoil at the idea of printed circuit boards (even if potted) and additional connections on a damp and cold and inaccessible British roof for 25 years and expecting them not to have failed or partially failed in that time. It’s an expensive repair just waiting to occur, even if replacements parts are available (which must approach zero likelihood).
But, at the same time, there is nothing for the consumer to use to see if their specific shading situation requires electronic remediation to work. So in my situation I have a mixture of mature pine and deciduous trees that are 200 ft away so the sun passes either over the crowns or just under and between, depending upon the height of the sun. It is literally impossible for me to know if electronic mitigation is going to give me a 0, 2, 5, 10, 20 or 40% uplift, so when it comes to performing a risk vs benefit analysis I have zero data.
It makes it even more complex when there are differing opinions and vested interests involved, the advice ranges from its essential to it will have negligible impact. It looks like you trade predominantly in the Home Counties, but we are in the NW.
One question, if you were submitting a G99 for a system that incorporated a powerwall 3. Would you apply for the full 11kW even if the panel output only required 10kW, I would have thought it obvious to apply for the maximum and then negotiate down if the DNO raised objections. I’m a bit pissed with my installer that he didn’t apply for the full capacity as I would have assumed (in case I ever need to add to the system) and that didn’t even discuss with me first. Or am I being unfairly critical?
While this is very interesting theoretically what I would like to see is a test rig (pair of rails?) with different panels fitted and a side by side comparison of what they generate in the real world. Spec sheets are a bit like petrol car MPG or electric car range - subject to a degree of wishful thinking!
The best solar panel is the one that faces the sun
Micro-inverters/Optimisers, more expense & more potential failure in the future...
Simply put, except for actual damage (golf-ball/hailstone etc...), will a solar panel potentially fail first or an optimiser ???
In vast majority of cases - the optimiser will fail before the solar panel, fit optimisers/micro-inverters to all panels & you will increase the probability of at least one (or more over time) failing.
So you will likely have to erect scaffolding, remove a number of panels to gain access to the panel within the array, possibly in the middle than right at the edges, replace faulty optimiser & replace the rest of the panels you removed.
(Chances of it being right at edge at fairly slim)
This replacement cost, may be carried under warranty, but what time frame before approval to proceed & remedial work completed - for the sake of an optimiser/micro-inverter failing
Ahhh - but the safety aspect, auto shutdown etc...
Well you've just tripled the MC4 connectors with a Tigo, 2 on panel + 4 on Tigo = 6 MC4's instead of 2
If you replace ends of PV strings with matching Stäubli's, as recommended, then the panel should also be replaced with Stäubli's to match the Tigo's Stäubli MC4's.
(Yeah, you could with the compatibility chart, but if so, then you wouldn't need to fit a Stäubli to either of the string on first/last panel as advised - in short, if you fit pairs of Stäubli's at panel ends, then you "should" replace all panel MC4's with Stäubli's, to match the Tigo's Stäubli's)
Now you've done all that, everything Stäubli, you still have 6 connectors compared to 2 previously on each panel. No matter how good these Stäubli's are, however snug & watertight they were made, there is still a 3 fold increase in points of potential resistance.
10 panels, you go from 10 x 2 MC4's = 20, to 10 x 6 MC4's = 60 - that's 40 extra MC4 connectors...
Admit, these are "connectors" that as a pair make half that as "connections"
(So std there are 10 PV connections Vs 30 connections with Tigo'd panels)
But no matter what, you've increased/tripled the weakest point in any array/string - the MC4 connector/connection
Personally, in an ideal world, if possible avoid them on a roof array, mostly as optimisers will likely fail before the PV panel itself does (excluding actual panel damage from debris/golf-ball/hailstone & no optimiser can prevent that)
DC arc prevention - clip cables frequently to keep all cable & especially MC4's off roof tiles & do not let them drape into the rails themselves - especially if using wide channel rail systems like K2. Do not allow the MC4 connector to sit in the channel of rail or drop into the surrounding frame of panel where it could sit in moisture/water. Clip the cable & especially the MC4's well up away from laying on tiles/roof/out of any rail-channel or slip into surrounding frame of panel- any of these areas where water can collect & potentially promote corrosion over time to MC4
Yes, could fit them on a lower install location, shed/garage/carport/angled wall mount - type of place where they could be replaced without needing a full scaffolding erected to gain access...
Yes, if a carport/shed had some shading, then I probably would consider optimisers on some/perhaps all panels, but on a main roof of a house - I'd tend not to, or only on a few panels that might require it...
I wouldn't kit out all panels on a 2 storey roof, that is just increasing the chance of one optimiser failing before a PV does
(Bungalow might be different, as may not need a full scaffold structure erected to remedy any issues)
Bi-facial panels - roof isn't going to see a massive potential gain
Flat roof/angled wall mount - now you might see a bit more potential gain from a white wall reflecting to the underside, but a black/brown roof tile - maybe not much
My own roof is SSE Gable with no shading - hence no optimisers
Might put up another modest string on a wall/carport as a sort of solar porch covering, but slight risk of some shading from a neighbour's hedge so I might consider a few Tigo's I have acquired.
If they need removal/replacing then it's an easy small ladder task, without needing to call scaffolding company back, but I'm a firm believer in less is more, or don't make things more complicated than need be
To each their own, but that is my personal take on it all and the reasoning in my own case/roof/array/system
Very good info. Thanks for the comment!
I would agree with pretty much everything. If they can be replaced (safely) with a ladder and the financials make sense then I would certainly go for them myself.