Standard vs Bifacial Solar Panels: Is the extra cost WORTH it?

[@Aphova]

Great work and well done for producing data to test your claims. A few of my takeaways/points: - The performance gap was bigger than I expected. I'm impressed! - I'm no expert so I could be mistaken but if that's the DC-AC performance loss, Sunsynk is lying on their datasheet or something isn't quite right. - Please, please, please use zero-axis graphs when reporting data. You have a valid point, no need to tarnish your image by making it look bigger than it is by using an axis that starts at 70% of the bar chart. - It's a pity you couldn't test regular panels with the microinverters and REA panels with the string inverter as that would've provided solid evidence for both technologies independently but obviously that would have been impractical 😅 - Personally, I think you missed an opportunity to hammer home a hidden win there: the REA/Enphase system was 18% more productive in summer but a whopping 60% more productive in December, when electricity use is often higher. Great job though, the solar industry needs MUCH more of this kind of thing!

[@Heatable]

Hey, thanks for your comment! You make some great points. We would have loved to be able to test those scenarios separately too. Funnily enough we took the 60% uplift in December section out of the video as we weren't sure it would be a section viewers would be too interested about. Great to know you spotted that though!

[@gavjlewis]

Realistically you want a minimum of 10-12 panels for a efficient string inverter of 3.68kW. If you are looking at a small system (like these 5 panels) then micro inverters are a good call or look for a suitably sized string inverter with a low startup voltage. I guess the big question here is what installer decided 5 panels were a good idea when you could clearly get 10 panels on the roof, which not only boost the peak output but also the voltage in lower light conditions for earlier startups and later shutdowns.

[@PVOK232]

On the background shot it has 2 DC isolation points. My understanding is that this was a 10 panel system originally before they swapped 5 out to test. Unless I’ve got that wrong?

[@PVOK232]

Re watched it, it was 10 originally

[@gavjlewis]

@@PVOK232 Oh ok. But my points above still stand. You can't double a 5 panel systems data and say that's what a 10 panel system will be. As for panels it doesn't really matter if using string or micro your installer should be using type N panels now as they have massively dropped in price and are only a few pounds more expensive than standard type panels.

[@Heatable]

@@gavjlewis As we said in the test, this isn't the most scientific, just a test that we carried out for our own curiosities and found some interesting results to back up manufacturer claims!

[@BumbleBeeJBG]

Hope this video gets millions of views. More content like this.

[@MrRogerWild]

Hi Ben, great video! I can vouch that the REA bifacial panels with Enphase microinverters definitely outperform string panels as claimed by the manufacturer. I have plenty of comparison data to back this up. (As you know I have a spreadsheet for that 😂). One thing worth mentioning is that where the REA-Enphase combination truly excels is when installed on roofs with shading. The difference is significant-my shaded garage roof with REA/Enphase even outperforms my main roof with string panels, which is completely unshaded. 👍

[@Heatable]

Thanks Roger! We definitely see it dominate in shaded installs, yours is a great example of this!

[@sentyuk5322]

I would have preferred to have seen the panels for the sunsynk swapped out for REA too. Youhave the data for the standard sunsynk system, but what made the exphase better, the inverters or the panels 🤷‍♂️. It’s been said already that you handicapped the sunsynk somewhat by reducing the number of panels too.

[@zamankhan4444]

You didn't mention how much energy loss you would get converting ac to dc when charging batteries, in my opinion that's where hybrid inverters out perform micro inverters

[@Heatable]

Good point, we'd expect a 3-5% loss when AC coupling a battery system. Worth noting that with an AC coupled battery, you can supply more instantaneous power to the home.

[@jetfu400]

these types of videos deserves more views. thanks a lot man

[@adon8672]

I know based on the anticedents of this channel that he'll not conduct a fair test. Is the 19-20% better performance due to the bifacial panels or due to the enphase micro inverters? Would you still get a 20% better performance if you'd swapped the enphase to the Qcell panels and the string inverter to the REA bifacial HJT panels? The string inverter has a higher start up voltage, in this case, 125V and it's at a disadvantage in your 5-panels test. Would you still get a 20% better performance if both string and enphase micro inverters were running on 10 panels instead of 5? If you had used certain string inverters like some from Tesla, Goodwe, SolaX, etc with MPPT tracking voltage and start up voltage around 60V, will the enphase still perform 20% better? Micro inverters have their places, especially in installations with extreme shading problems. Similarly, bifacial solar panels are best in ground mounts and other installations with at least one metre clearance behind the panels where reflected light can enhance their performance. You designed this dubious test to produce your desired results. it is sad that solar experts are willing to mislead their viewers and customers for selfish interests.

[@MrRogerWild]

As I understood it, I thought they were testing the bifacial panels and micro inverter as a combo against mono panels using standard hybrid inverters, even though the title said standard v bifacial panels I’m no expert like yourself, and I get your point about mixing the equipment to test and gather data on each component. Using more than five panels in a test would have been great, but given the space available on the roof, that looked challenging. When doing real-world testing, you can only use the environment given. I suppose even a 1x mono panel vs. 1x bifacial would still provide some comparison data. You are correct about the higher startup voltage when comparing inverters, but I suppose that’s the point. They were bench testing real-world conditions, not ideal test lab conditions. This provided equality, not equity, and customers just want to know what solutions give them the best return. Regarding my own system, I have both solutions: mono panels with a standard inverter on an unobstructed roof, which performs well when the weather is great, though not so much during the winter months, partially due to the higher startup voltage you mentioned. I also have REA/Enphase on my garage roof, which suffers from obstructions and shading. This is the main reason why I chose this combination over other solutions I researched. For me, this solution works well all the time, including cloudy days and even during winter months. While it doesn’t generate as much as in the summertime, given its less-than-ideal location, it always outperforms my string panels. As a combo, the REA setup performs much better than the standard panels and inverter, and as individual components, they are better too. However, when combined, they are superior together. I suppose the question I would ask myself when it comes to replacing the panels on my main roof is whether I would fit mono panels with a standard inverter or the REA combo. Based on my own personal data, I would definitely pay the extra and go for the REA/Enphase solution.

[@UpsideDownFork]

Start up voltage is too low on 5 panels for the 3.68kW inverter. 10 panels will see that SunSynk performing much better, starting up earlier and finishing later. It's a good test but not a fair one...unless youre only going to fit 5 panels on your roof. It would have been better to find a neighbour of your customer with an identical roof to have your enphase/REA system fitted and then compare 10 vs 10 in the real world. The extrapolation of data by doubling is not really valid im afraid. Anyway, good on you for putting your money where your mouth is and sharing a real world test 👍

[@ChickalataRUBY]

I have an 11 panel system, split across two roofs (5 + 6). I see a lot of houses with 4 or 5 panels on like mine, surely they don’t have two inverters to do this?

[@UpsideDownFork]

@@ChickalataRUBY smaller inverters or more likely, split across two strings on a single inverter. Both strings will still contribute to the startup voltage. Even shaded panels will still produce startup voltage. It's the current that increases dramatically with stronger sunlight.

[@smc812]

He could have also added together the Load and Grid number from Sunsynk to get the AC side of the export data, rather that suggesting the data is exaggerated. I get about 9% difference between in and out on my 5KW Sunsynk, but some of that power is going via the battery. I imagine your system without batteries will give you a smaller figure for inverter losses. Shame the Enphase doesn't show inverter losses on their side.

[@steve_787]

@@UpsideDownFork I asked Heatable the same question on what the drop in start up time was by halving the number of panels but they never responded. I'm not sure about you, but I'm not seeing the sort of losses from how the Sunsynk app reports production/export vs what Octopus pays you? Maybe something for a video on your channel, see what Sunsynk reports as exported vs what Octopus record?

[@UpsideDownFork]

@@steve_787 my sunsynk inverter consistently under reports the export by 5%. That's compared to both my generation and smart meter.

[@steve_787]

Just a question/thought, my understanding is that string inverters have a minimum start up voltage. Would reducing down from 10 5 panels have affected how early the string inverter would have fired up? Gains would be negligible but just curious. Great comparison though.

[@davemorris661]

Nice job. Been waiting for this. Just curious now this test was started a year ago what difference you’d get with new hybrid inverter tec. The hybrid inverters on the powerwall3 (60volt)and the sigenstor(100volt) have a lower start up voltage than the sunsync used(125volt). It’s all interesting stuff. Curious if the differences are panel based or inverter based.

[@Animosity6792]

Yeah that would be interesting to know. Either way they aren't going to get the best out of the SunSynk with only 5 panels!!

[@NathanJones-cq1dz]

One month on after having two installs with one being Jinko Neo 440 panels via string and the other REA with enphase 8 microinverters. Comparing generation per panel, the expectation was that the REA would perform 20% better but that is not what I am seing. If anything, I am seeing 20% less generation. The claims are that microinverters activate earlier and stay on longer. Again, this is not my experience. Overall I would recommend Heatable for service, I would however not go with the extra expense of REA and microinverters if I were to do it again.

[@agilani01]

What inefficiency is introduced when adding batteries to the enphase system as the DC is converted to AC and then back to DC to charge the batteries?

[@Heatable]

There was no batteries run on the test. There are various opinions from manufacturers would be losses of approx 3-5% would need to be factored. Worth noting that with an AC coupled battery, more power can be supplied to the home rather than limiting the hybrid inverters max output.

[@gosolxsolar]

1) You didnt mention if the Hybrid system is using optimizers? In the USA optimers are required for rapid shutdown by NEC. So, you would always have those with a string inverter and it could affect things. 2) Why are you pairing 420 watt panels with microinverters that output only 290 watts? The micros on my roof and those I install for customers output 386 watts per panel. So, virtually no clipping. But the panels will frequently output 350 watts continuously for hours. That would be 60 watts of clipping per panel. Yikes. 3) You cant realistically get a good comparison with 420 watt panels on one system snd 400 watt panels on the other and also have 1 be a hybrid and 1 use micros. Just too many different variables. You seem sincere and likeable, but sticking people with IQ 8's is troubling.

[@Heatable]

Thanks for the comments, in response - 1 - no optimisers, as not required in the UK. 2 - The panels are 400w, average irradiation here in the UK is 500-700 watts/m2 which is why the IQ7+ were a good match for the 400KWp panels. 3 - Both were 400w. Hope that helps

[@gosolxsolar]

The 395 watt Canadian Solar panels on my own personal roof north of Seattle has a similar weather pattern to the UK and regularly output between 320 watts and 350 watts for extended durations. Yes. The average output on some sunny days may very well be 290 watts, but so what? IQ7's are still clipping off lots of legitimate production.

[@vlodo001]

Good video, but the title of the video doesn’t match the content

[@Heatable]

Glad you enjoyed it, feedback noted :)

[@philipelliott5821]

Difference in cost of each installation??

[@davesoton20]

It would be good to see it with a plain string inverter but the only accurate way is to test with the same datalogger. I have it with Solis under reading its output so you can never compare two inverters accurately using their own data. Did you check the power factor on both systems? It would be interesting to see two sets of panels with either the same model string inverter or micro inverters so we can see the actual panel difference. The string will be more efficient as the system voltage increases.

[@Heatable]

Hey Dave - agreed! The next interesting test will be to investigate the real difference between the REA bifacial panels and the microinverter set up to see if it's just as impressive without the technology working together and how a hybrid inverter set up compares.

[@Stune5]

Nice to see some data to back up the theoretical claims. Worth pointing out the comparison is between 400w panels on the original install vs 420w panels on the newly fitted section so there should be a 5% uplift as a minimum. Good to see the results comfortably exceed that. I'm surprised we didn't see more clipping on the Enphase setup given the restrictive nature of the iq7's. I would be interested to know which day the data displayed at 8:58 was taken from? Generation from 5am to 8pm suggests a June or July day? Depending on the slope of the roof, clipping may be more likely an issue around the months of April, May, Aug and Sept so it would have been interesting to see samples of a few more days at varying times of year. Worth noting also the results with the latest gen of the REA panels they now sell and the iq8 inverters (especially if you upgrade to the HC model) would be a fair bit better than this too.

[@Heatable]

Hi, thanks for the comment. Both were 400Wp panels. I'll check with the team on the 24 hour period data for you. The team are now installing the some of the ACM panels which are the 440Wp panels with the integrated IQ8HC's. We should have a video on this soon. :)

[@guywhoknows]

I see what you've done, but .... You have compared a string to a single panel track, one converting the other not. You also missed the cost difference and also the life span difference. Miss matched panels will run at the lowest for all of them with a string inverter. I can confirm there can be a big difference due to panels alone. Which would cause an issue with data. Now production and usability. Enphase does not have a battery, so you're not storing power to use later at night. This could be seen as adding to the cost of ownership, together with the higher price of the hardware. You could say you lose 15% for 50% more costs. Or we could just look at a 420w panel which only gets 290w usable... Stats will only look as good as you want them too. 😊 But for part systems, with AC coupled battery inverter... Going to be better than a sting inverter and offer flexibility and suitable for more complex installs.

[@SimonEllwood]

You could add another inverter and connect that to the battery. It would need to be AC coupled but would still allow charging from the sun and monitoring.

[@NathanJones-cq1dz]

Great comparison and looking forward to my installation of Fusions and IQ8's next week.

[@Heatable]

Thanks Nathan, looking forward to getting your system set up!

[@andy9841]

Great video, I wonder what the difference is between the Fusion 1 in this video and the Fusion 2 panels they sell now

[@Heatable]

This would be a great future test as the Fusion 2's we now use are 440W and we used IQ7+ microinverters, where as with the new IQ8 range, it would allow for more production with these higher output panels.

[@zerokelvin-273]

I have a question how old were the hybrid panels system what % of this difference could be attributed to old panel Vs new panel it's proven that efficiency is lost in the first years and then plateau until failure

[@Heatable]

HI, great question. The Hybrid panels were around 9 months old at the start of the test.

[@ChickalataRUBY]

Good video guys. I know why my inverter readings are way off to my smart meter now 😂 I have a string system which has two arrays, 5 panels on one and 6 on the other. Definitely going for micro-inverters on the new house.

[@Heatable]

Glad you liked it :)

[@tangent2658]

Frustratingly, because you have chosen to use different pannels with different technologies on each, we cannot see the difference in gains from just the microinverters compared to the hybrid. I get why you have done this, you are comparing your services to the rest of the market but my inner scientist is screaming ONE VERIABLE AT A TIME! :D :D One comparison I would love to see would be an REA system with microinverters pitched against a tesla powerwall 3 and its hybrid inverter. An even more interesting test would be north facing vs south facing with the REA and microinverters. There are some KZbinrs that have been going down the north facing expansion and results seem promising so far at 50% of peak generation or more and I believe that is without bifacial or microinverters. I'm very torn on the whole micro vs string aspect. Each micro being a potential point of failure that would presumably require scafolding costs to resolve, which I'm assuming the warranty wouldn't cover vs the costs of replacing an inverter at ground level covered by warranty. What I have found with the PW3 is that if its inverter fails you can just buy a new PW3 and use the old one as a battery expansion, which is an interesting scenario. Its all a bit mute for myself sadly as I'm trapped in a shared ownership nightmare where they will not allow me to install things like solar or heatpumps until I mortgage the other half of the property, which is a few years away at best, so I can probably get better data in that time. I may be able to get away with a battery system to use offpeak rates, however.

[@treeoflifeenterprises]

great to see bifacial is 20% more production, but what is the price difference? it would be good to compare cost of production/panel with microinverter based on 10yr lifespan to know if that 20% extra is cost effective. also useful to know that the batteries need to be charged so they don't break. making sure production is enough for that is another useful consideration to be aware of.

[@Heatable]

We might look at doing this as an extra video to give some more insight into how much more or less the system would cost over a 10 year period!

[@treeoflifeenterprises]

@@Heatable great, thanks

[@RS.Outdoors]

Is it possible for an average 2 bedroom end terrace house with say 8 south facing panels to generate enough electricity that you don't have any bills other than the standard charge. Looking at cost of systems to lower my bills for when I retire to keep my monthly bills as low as possible due to pension limitations. After watching reams of videos still cant see if it is worthwhile.

[@steve_787]

Would all depend on how much energy you already use and how much that costs you. I use a lot of elec (9000kWh pa inc. EV charging) so my 18 panel system I hope to cover 2/3 of my usage. I'll then able to take advantage of the battery to charge overnight on the cheap 7p/kWh rate during the less sunny months to avoid peak rate prices. Couple that with the current export rate of 15p/kWh and selling a good chunk of the production, my net bill for the year should be zero and hopefully cover off some, if not all, of my standing charge. But I'll still have a gas bill. My system was £11500 (not a straight forward install as it was over 5 roof faces) and depending on what happens with energy tariffs over the years I'll break even in 5-7 years. The way I see it is that I'll be paying for electricity anyway, so if I could finance the system to match my current monthly costs then I may as well. Then one day I'll be saving £200pm over night and won't look back.

[@embracefoundationuk]

You'd need a battery and off-peak charging in winter to maximise your immediate return on investment. Don't forget, the value of your property will increase if you install solar/batteries.

[@Heatable]

Hey, as Steve's commented below, it does depend on how energy you'll be using. If you know how much energy you use currently, you can put this in when you get a quote (link above) and it can tell you how much you'd be saving or estimate it for you.

[@omsval1485]

How would you stop the clipping, and would it be worth the upgrade because I’m guessing it only clips a few days in summer

[@MrSeanUK]

I have the Enphase IQ8AC micro inverters which do around 360w peak. I had clipping on 24 of the 31 days of July. I guess using smaller panels is the only way to stop the clipping but it's hard to know what the best option is.

[@omsval1485]

@@MrSeanUK Smaller panels would probably mean more inverters for the same size system.. for 6-7 days of energy, it’s probably not worth it

[@davemorris661]

@@MrSeanUK I don’t think the clipping losses would be too much over the year. I’d just like to see it with good panels like the Aiko Neostar with a lower start up voltage hybrid inverter like the ones in the power wall 3 or even the sigenstor with at least 6 panels per string.

[@embracefoundationuk]

I love watching your content, however, the title of the video is misleading. Is this about the panels or the different inverters? You could have undertaken two more variations on this test by mixing the panels with each inverter type.

[@Heatable]

Hey, thanks for the comment! It's about both, ideally we would have had the opportunity to test an REA panel with a hybrid inverter and microinverters and then a standard panel with micros and a hybrid inverter too. To get a fair test they would have to be next to each other, so it just wasn't possible at that time.

[@embracefoundationuk]

@@Heatable is the cost difference greater than 20%?

[@talpolano4549]

Next test make bifacial be install in an elavated level so that can reflect more on the back side

[@shaneclk9854]

A battery being off for a year breaks it? That's bad rep for sunsync they should replace the battery

[@electricandlspower]

It was probably loose. the one next to it is not fully installed.

[@davideyres955]

Can you have the micro inverters inside the house?

[@Heatable]

Hey David, the microinverters go under the panels on the roof.

[@Animosity6792]

Those bifacials are uuuugly! What model number of REA panels are they??

[@Heatable]

These are the very first model we had over a year ago. Shortly after we started the test, they had a glow up and are all black panels now (so look a lot nicer).

[@mr.hamiltom5440]

This is absolute garbage from a scientific point of view. It is also very misleading for the uninformed.

[@Heatable]

As we stated in the video, we did this for ourselves but after finishing the test we thought it would make an interesting video to show the difference when you combine Bifacial panels and microinverters and compare the results to standard panels and a hybrid inverter. Definitely not the most scientific, but by no means misleading...

[@armandvermeulen2947]

Sunsynk still better

[@jonbraathen2232]

The test is inaccurate. You should have same types of panels on both inverters to compare, of course the older one sided panels performs less than the newer doublesided ones. Its not the inverters fault. Test is rubbish.