I attended a Canadian Solar demo class on these bifacials and even their experts didn't do a better job explaining how good these panels compared to your explanation, Keep up the good work buddy.
Hello Dave, I wanted to say a massive thanks for all you have tough me regarding solar. I now have my system up-and-running. I changed plans several times as each video you posted made me re-evaluate. I now have 64 bifacial panels on 4 ground racks of 16 per rack. I have done as you suggested and placed two racks at 45 degrees from due South. One at 135 degrees SE and one at 225 degrees SW. The remaining two are due south. All have an azimuth of 36 degrees. The resulting performance is way beyond my expectations, interestingly, the SW panels produce half the power that the SE array produce in the early morning. This must be just from the back side of the SW panels. So pleased I changed my mind and went with the Bifacial panels. I also followed your advice and split the load on each of my two inverters by running racks 1 & 3 to the first and 2 & 4 to the second. I knew nothing about electrics before I embarked on this project, let alone solar! None of this would have been possible without the education you have given me. The clear and concise way you explain the process has been invaluable. I am in your debt. Keep up the good work. Regards, Richard.
Richard, thanks for the encouraging feedback! I love that you have taken all the things I've learned from my install and analysis and made a much better solution than I did for my original install. I'm so glad my information could make a difference for you!!
Hey Dave! Great video. I'm in New Mexico and I know a guy who did a neat trick with his bifacials. He mounted them as a pergola roof about 15 feet up. And on the ground he put down white concrete unnder the panels and white gravel 20 feet out from the panels. He said he saw a notable increase when he added it.
I picked manderins years ago ,and they had a white geo-textile pinned under the trees specifically to reflect light to the underside of the trees - and help the fruit rupen quicker , same thing really .. Wether you'd want thousands of acres of plastic fabric everywhere is another issue though ..
Thank you for another great video. I am installing a ground mount system right now. One thing you did not mention was Bifacial racking, I managed to change my order for racks that are specifically designed for Bifacial and have no supports crossing the back of the panel. They adjust to the panel size. I was also able to get new Longi 445W Bifacial panels for only a few €’s more than the same watt standard panels. Interestingly, the Bifacial come with a 30 year performance warranty as opposed to the standard Longi panels 25 years.
Thanks, good point! I did forget to mention the racking considerations. I think they can offer a longer warranty because they start at a much higher output with the backside boost and the backside glass is a better material then the typical back sheet.
That was the most comprehensive presentation I've ever seen! Although I'm not that great at math, I understood your explanation perfectly. Well done sir!
should lay your bifacials on there side. keep panels a little more vertical and step each row back the width of panel.[like a set of stairs] you should get a reflection from front of second and third rows plus less snow in winter. would be nice to see thanks. make your stand a just forward or back for summer or winter
Outstanding content. Conclusions on bi-facial panels I've had to piece together from a myriad of sources...almost all confirmed in one video. I think the only belief not specifically confirmed has to do with backside gain being able to heat panels enough to shed snow cover on the top side from the heat produced by power generation entirely from the back side. Ground-mount panels set to a steep winter angle for a lower sun should automatically shed snow early in the day and provide substantially more power than panels with cells only exposed to light from the snow-covered top side - all with no manual snow removal activity.
To get more benefit from the backside of the bifacial panels, you could apply something shiney ( foil on foam, foil tape, etc ) and mount it on plywood. Then install the plywood behind the bifacial panel mounting rack so that at peak sun reflection, the plywood+foil sun reflection hits back side of the bifacial panels.
I use twin 3120 watt bifacial arrays on dual axis trackers and during the summer I maxed out at just under 6700 watts. I placed the white granite rocks under my panels in order to catch as much reflection as possible plus my panels are elevated so I get reflective light from all angles.
It's nice to see an actual in depth comparison of bifacial to standard panels. I too live in ohio and plan on doing solar at home but im waiting on the paperwork side of things and ive missed out on panels and inverters so far because of it. But my plan is now to get 20 445watt canadian bifacials, two sungoldpower sp6548 inverters, 30kwh eg4 lifepower4 to run my whole house. The array is going to be mounted at 45° because i have a friend right down the road and he gets the best all around output at that angle and it should shed snow decent. Im going to have ac input with the inverters if/when my solar cant run the whole house in the summer bc the 3 ton ac unit. I use around 45-60kwh a day(summer) so im guessing it'll handle it.
I think the steeper angle is a good choice to maximize winter production. However, if your max consumption is in the summer, you may want to go with 30 or 40deg.
For best radiance, make sure the reflective material is curved [to gather more IR] and farther away from the back of panel. Ideal IR would be a hemi-spherical 'cup' that will be focused towards the center of the array.
Thank you for the insight. Im thinking about putting high quality reflector under my 400watt bifacial solar panel. Can you demonstrate this technique and show the difference, if any. 🤩 THX.
I used Canadian Solar 440 bifacials and put them above a galvalume metal building (low slope) roof, with a racking system that allows me to tilt up for winter, and down for summer, in both cases my panels are well above the metal roof. Being near the 49th parallel, the panels have sun Behind them for a good stretch of the year, and lots of reflection during winter. My best production ever is acturally January and February when it is cold, and lots of reflection from snow and metal roofing. Yeah those high production numbers are only for a few hours per day, but when you need every watt, this is important. I have seen over 115% of rated capacity on many sunny cold days. One thing to be careful with - Put your framing only inline with the panel edges: no strut running in the middle of the PV back side! keep all the wires and any conduit or wire way away from anywhere they can cause shadows!
You should do a video between micro investors, optimizers, and 1 charger/installer that you put in the house . Would love to know which one performs the best and gives you the best efficiency
Yes I had an idea as soon as I heard about by facial solar panels They make a paint that is so white. It actually keeps the surface underneath it 15° cooler than ambient temperature So simply paint the concrete slab underneath your solar panels with that ultra white paint and you would probably get a copious amount of bounce back
So one thing I read somewhere is that you should consider increasing the tilt angle from the ideal at your latitude by 5 - 8 degrees and also raise the mounts as high as you can. They also said that you should increase the ground area below the back of the panels you cover with something reflective, like white stones.
Since the power boost is going to have the biggest increase in mid summer it makes sense to adjust the tilt angle to favor winter production, that would result in a more even production throughout the year. Another advantage of bifacial! If you have a link to the information you read feel free to post it here. Thanks!
I wish you would have tried them with white metal roofing under them. We are building a net zero condo with a 3-12 pitch white metal standing seem roof. I'd like to try them.
Thanks for doing this research! It is interesting with bi-facial, half-cell, different bus bar designs, and microinveters how much better panels are with shade and how much more real efficiency they show. Those NEP 600s are clipped at 390W per PV input, you may have had more! I am looking at doing a similar system with AP Systems DS3s and the Aptos 440w bifacial from Signature Solar, which also may experience clipping! The one thing that I am still trying to figure out is racking, do you like your Ready Rack system? Would you have gone with this system if you were doing things over again? I'm looking to do a ground mount with 30 72-cell panels, I would love to have it seasonally adjustable tilt and don't care about aesthetics. However, it seems like tilt adds too much money and these static mounts are likely going to be the best bet.
I do like my racking system and I would go with it again. There is a single pole system with manual tilt adjustment one of my friends is installing that would do what you want, but it requires special equipment to drive the posts so it would be more expensive. I only connected one panel to each NEP microinverter so there was no clipping in my results. The BDM600X is capable of 580W output per inverter. I got the same result from the microinverter and the optimizers.
Great description and analysis. Considering these to refurb my ground mounted system. Season tilt for Lat 50 means they are almost vertical, slight hill and snow behind the panels would mean quiet a boost. Also -40'c has significant effect, watch out for your Voc Max!
@@ProjectsWithDave Yeah, I'm curious if the perform better in winter months too when they can get more light underneath from reflected snow. I live in Illinois, so really wind power would be a better option, but solar is going to be easier of an install and serve as an awning of sorts too.
Bifacials are highly recommended when installed on flat rooftops without tiles painted white and always installed on angle (this is the case for many buildings in southern Europe). They are very efficient when the surface behind them is reflective.
@@ProjectsWithDave In that case you stick with the normal half cut, mono PV. I mean, if racking costs double the money just to put some bifacials, it's better to avoid them. Watching your video experiment regarding panel orientation, I'm thinking of using a couple of big power output bifacials in EAST-WEST direction for harnessing sun early in the morning and late in the evening, especially during winter. That's I think is a more appropriate and efficient way to use these panels if you can't install them the right way.
Based on my most recent analysis, I think the best orientation would be SSE and SSW. You can see those results here: ruclips.net/video/J7xnY84Ch1E/видео.html
Man you must be super happy with yourself for producing such monster Size boys at the very least man KUDOS to you I would be and I have 10 410w bi Facial panels from signature solar I’m drawing a blank right now on the manufacture name but I have yet to mount them so when I seen this title I had to watch this asap thank you so much for taking the time to make these awesome info packed GEMs 💎 that anyone thinking about doing solar for themselves or others can’t go wrong starting with your content
GREAT video. I am in the process of upgrading two of my arrays to Q-Cell 480w bifacial panels. I have one array done and can say the performance of bifacial has def improved vs my older Renogy 100w panels...esp in low light (cloudy conditions). My arrays are all ground mounted.
They have short leads, so if you are not using a string inverter you may have to make lots of MC4 extension cords. Otherwise I have found them to be superior in almost every other way.
How about a reflective surface laying flat or at an angle reflecting sunlight back towards the back of the panels. In fact it might even work top side reflecting sunlight that might normally past the top side of panels back towards the panels.
Just found this video so I'm a little late to the party. But, I can attest the Blue Sun 460-bifacial panels are awesome. We put 12 on top of our barn with S5 Protea brackets above very light colored AG panel and the results are incredible. Actually a bit too good to believe. Last weekend, just before peak sun, with only 6 of the panels turned on, our Growatt inverter read it was receiving 122 watts @ 30 amps from the 6 panels. If that's truly the case, we're just over 600w per panel. I need to touch base with Signature Solar to see if that's even possible. Or possibly it's reading incorrectly. Either way, we're generating all the power we need. Thanks for making awesome videos!
My inlaw has a cliff wall in the front yard in the Berkshire mountains. Im moving there going to put those pannels in front mabe 10' and paint a reflective rock wall. Aney paint recommendations 😮
That’s all doesn’t matter. What are real numbers is a price to watt ratio, internal resistances (direct and back), and a durability of a surface. I’m sure it’s possible to find a 10% less expensive standard panel, or 10% more powerful for a same money. And to use a good mounting, wind proof, etc
Hi Dave Have you tried mounting the Bifacial panels vertically in the North south direction so they get morning sun on one side and evening sun of the other ? At first thought it doesn't sound intuitively correct but then who who would have thought you would get the results you did with Bifacials. It would hugely boost early morning and late evening production which is the most useful/useable times of day. You also get snow in winter which would help with the refection (I'm in KOPU New Zealand and only get a few frosts a year). Perhaps East West ?? who knows as they are new technology that is allowing a whole plethora of ideas
Yes, I have a test running now with vertical bifacial panels. So far, they have good morning and evening performance and on cloudy days they perform very close to the south facing panels, but overall, they still underperform the south facing 30deg panels.
@@ProjectsWithDave thank you for your reply. Much appreciated Immediately after I sent that question I 'discovered' alot more information online about them since you did that video 10 months ago and the orrigional German study "Smart Energy" published Aug 2022, where they do vertical bifacial panels to be able to use the ground for other purposes eg agriculture. There are lots of smart people out there coming up with all sorts of new ways of using things and with the internet to make it accessible it's amazing. I'm a 70y old ex research scientist (the ex just means no one is paying me now) but we never stop learning. I like your videos as you measure and calculate stuff in a robust manner that's consumer friendly (a big problem with alot of science). Virtical bifacial panels over water. Now that's an interesting one. Reflection and cool air, dual use of area for fish farms and dams ? The permutations are endless Thank you.
The solar space is fun to be in. As you said you never stop learning, and there is always something new to learn and experiment with when it comes to solar. The combinations are truly endless.... : )
Thanks! I live in the Okanagan, British Columbia, Canada. Orchard growers lay white plastic on the ground between the rows to reflect more light back up at the fruit. Might work for this too when you don’t have snow. I specify high albedo (white) roofing on flat roofs with bifacial solar arrays.
DuPont house wrat available in 9' x 200' rolls. Roll out and stake down under the bifacials. Not as reflective as snow, but it won't cover to top face.
I'm planning on dipping my toes in a small off grid system to keep the freezers and computers going and these panes are intriguing as I was thinking of installing them on a galvanized roof of a metal building. The south facing roof pitch is only 2 degrees so I would use a little more tilt on the panels to allow the morning and late afternoon sun to bounce off the shiny roof and onto the back of the panels.
If you plan to elevate the panels off the roof at a diverging angle, I think you will see a noticeable benefit from the reflection. I think you would need 18" to 24" at the back edge to see a significant contribution.
I did just that. My battery pack runs 2 full sized 24 cu ft self defrosting refrigerators, an old 24 cu ft upright freezer and a 5 cu ft chest freezer. I bought the Signature 410 watt bifacial panels last year not knowing what I was doing. I have 4 panels at 40 degree elevation on a roof deck, and another single 410 watt damaged panel on the roof with no back lighting. My sun exposure is far from ideal but better than nothing. In August, they work well from 10AM to 3PM. At this moment I am preparing to install 4 more on the roof. I have aluminum channel mounts and ran into the clamp problem. The panels are 30mm thick and the middle Tee clamps work just fine. The end clamps needed modification to hold tightly. Most clamps are made for 35mm to 50mm frame thickness. The panels are about 40x80 inches each. I mounted them horizontal lengthwise, 2 rows of 40x160 inches on that 40 degree home built triangulated frame. The low profile won't catch the wind like if the panel was mounted vertically. I got really good at making MC4 jumper wires after buying the cable kits and with strippers and crimping tool. The gender of + and minus outer sleeves with OPPOSITE gender inside contacts was confusing at first but I can do them in my sleep now. They were clever enough to make sure the internal + and minus crimped contacts are different sizes to make them goof proof. Remember PPP on the solar panel output wire... Panel Prick Positive ...the male end is positive. All solar panel MC-4 female connectors are negative. My batteries stay between 80% charge and 97% charge so far. That old upright freezer is a real energy pig and runs at about 480 watts. I have 2 chest freezers, 5 and 10 cu ft being tested right now and they run at about 77 watts each, far cry from the 1984 built freezer. Good luck!
Buy the solar you need now. Prices are cheap but they wont be for long. Bifacial panels when this was made is $200 plus, right now it is $120 for a 400 watt panel.
I have an idea about how to maximize light to both sides of bifacial cell. Put a long cylindrical parabolic mirror underneath the cells. Place cells in a line parallel to the cylindrical parabolic mirror with the back side facing into the mirror, front side directly facing sun. This arrangement allows for rotation of the parabolic mirror with the cells to always face the sun. I bet you could significantly improve performance. There are some challenges to overcome but idea is sound. This technique would also work with regular mono cells with front side facing down. I am working on a prototype so as to get some real values.
Maximizing bifacials ideas: Dolomite gravel as ground cover underneat, in the same fashion: Marble gravel under the panels, both reflect significantly more light from the ground. A even more expensive option is the white reflective paint used for road lines, tumble any rock in a bath of that paint and a highly reflective and durable ground cover will be produced.
@@tommak6516 only those last 15% or so of extra efficency you can squeeze out of the double sided panels. Been doing some trials for "winter electricity" with 90 degree "standing" panels and reflective white paint on the wall behind them, roughly 1.5 meters distance also the ground 0.5 in front and spacing them with 1.5 panel-width gaps to the next in the row (chucked up 10 of them for testing purposes against a barn wall painted in reflective paint roughly 3m up the wall) Panel size where 2.2mx1.2m (largest bifacials I could find).
@@tommak6516 Mirrors are optically grey, so less reflectance than white. Despite the perfect mirror image of coherent light rays, homemade mirrors are less optimal because of potentially damaging lensed specular high lights and unpredictable effect of shadows on current flow. We don't need to boil water here. And even if a perfect mirror would be able to be made cheaply and durably, the panels don't even need to see a perfect 1:1 picture of the sun. White coating is: cheap, can be found in many forms, easier to repair and maintain. This is a missed element.
Im looking at a simple ground RV install with a simple hinge on one side, a reflective surface on the other and hinged vertical for tilt.Then tilt them to the sun. Im hoping this simple clam shell will support them during storage but I fear the will be getting pretty heavy. I might need slightly smaller panels
The Mykonos postcards will never be the same once the greeks realise what perfect combo white roofs and bifacial panels are. Come and take your vacation photos before it is to late.
The issues with the pannel thiskness and cable length are a function of the manufacturer, not because they are bi facial . Aptos makes a bi facial with standard thickness and 1 meter cables, they just cost more than some odd commercial brands . You have to weigh the cost of cable extentions when pricing pannels , as the cabling costs can add up .
Would it be interesting to test with standing panels so that they get sunlight in the morning from the front andin the evening from the back side? the floor covered with aluminum zinc roof sheets. i could imagine that the output it is more than the normal south direction installation
Two-way Infinity mirror film it's freaking cheap you can wrap it around wood who cares if it gets hit by weather and you can make 4 ft by 8 ft sheets out of OSB board and direct the damn sunlight to it Make it so number one you can get the stuff at Amazon
Too bad you didn't test the down face of this biracial solar panel to its full extent, like with a smooth ultra white ground surface, ground- mounted high enough so that the down face gets reflected light not just from the back but also from the front, maybe try with a mirror film behind the panel to reflect even more light, get a fan under the panel to see if cool air benefits productivity, this kind of tests that come to mind with bifacial. Your huge wooden frame is also a big hindrance for bifacial panels. Better use thin flat metal just under the sides of the panel, so, customized to its size. And really, you should not even mention rooftop mounting for bifacial, when rooftop panels should be as thin as possible and ideally part of a weatherproof roof design rather than looking like roof warts on top of another roof. That second face won't get used at all, although your blocked face tests show that there is some extra efficiency, possibly because some light that manages to cross the topside gets reflected by the second sheet of glass at the bottom thus converting more electrons, or some other cause that would be interesting to know.
Have you thought about a mirror or a white reflector below your array. An array of mirrors would be a a lone off cost but radiator reflectors would be a good trial an these bifacial panels.
It's a scam. If people say it's a 100-watt panel and its only 80 walls on a best day than it not a 100-watt panel, it's an 80-watt panel. Don't lie to people just say it's an 80-watt panel.
Hi Dave, another great Video, I just received 21 CS 450 WATT panels from Santan, almost had the same unloading problem that you did. The truck driver had a powered pallet jack and almost run it off the back of truck, lucky I had my skid steer with forks and got under the pallet before he dumped it. I am building my own ground mount, and putting up a 31 foot car port and using one side of the verticals of carport structure to attach Unistrut @ 30 degree supports for my mounting rails to attach to . Won't get the best performance on back side, but can't beat the price for panels. Now I am looking for an Inverter, and leaning on using a Growatt 7.6 kw or 10Kw as to not get into clipping hybrid inverter, they seem most reasonable priced and have a battery backup option that can be added latter.
Using panels to serve as a roof and power is a great strategy. If your orientation isn't ideal, you won't likely make much use of the 10kW inverter. You will probably be fine with the 7.6kW.
It sounds like ground mount is a much better way to get production then rooftop. How about trying some reflective materials underneath the bifacials? Reflectors or mirrors.
I plan to try a white steel roof later this summer. Mirrors would likely be helpful, but delicate and hard to position. I was thinking mounting with a pond backdrop might offer good reflection.
I live above Loch Ness in Scotland and am currently building a house to rent out on my property, which I bought with planning for 3 houses. I have heard about bifacial panels and am going to buy some for my house, which I hope will run on solar power. I am going to put some kind of reflective material on the ground beneath the panels. Can't see why this wouldn't work! But maybe I'm wrong here..............
I ran a test a few days ago with reflectors for my vertical panels I will publish that most likely in August. You can get some idea of the increase in performance from reflection from this video with reflection off the snow: ruclips.net/video/YZWeCUzu0yQ/видео.html
@2:55 and THAT is one of the most common ways to LIE with STATISTICS. Graphs that zoom in on the end to magnify the difference. "you can clearly see just how much..." yeah... The only reason you can "clearly see" the difference is because you're not showing 75% of the graph, where they're THE SAME.
Thanks for your feedback. Dropping the bottom of a graph is not lying with statics. It is a common way to make the delta more visible. The scale on the side hasn't changed. Clearly you were able to understand the magnitude of the difference. My goal is to always show the actual data in as clear a manner as possible. I have no agenda or reason to try and show something that isn't true.
Can you try setting up a test with some type of reflector.. Like outdoor aluminum theremal insulation, white acrylic roof costing or cool metals roofing under the panel.. It might work great on flat roof in my opinion
Im wondering about the comparison between a standard panel that have a cooling system in the back vs bifacials. As we know, heat decreases panel efficiency.
I would guess a cooling system would cost much more for the boost in performance than the cost of bifacial panels or even just adding more standard panels.
I know this video is a year old, but if you're still looking for something highly reflective there's this grow film called Orca film. 94% reflective, 99% diffusion. Might be worth looking into.
What would harm putting mirrors (stainless steel) on the ground reflecting sun hitting them directly an reflecting up onto the back of theses BIFACIAL panels?… INCREASED production (A LOT), right ?
Based on my winter results, I don't think the cost would be justified. You can see the results from the reflected snow in this video: ruclips.net/video/YZWeCUzu0yQ/видео.html
I attended a Canadian Solar demo class on these bifacials and even their experts didn't do a better job explaining how good these panels compared to your explanation, Keep up the good work buddy.
Wow, thanks!
@@ProjectsWithDave it's worth test it out. Also, try spray painting gravel white and silver. Because it will reflect differently.
If you give me credit, please change remember to change my last name to Gardner. I am getting ready to do make it official soon.
Mirrors onthe ground
Hello Dave, I wanted to say a massive thanks for all you have tough me regarding solar. I now have my system up-and-running. I changed plans several times as each video you posted made me re-evaluate. I now have 64 bifacial panels on 4 ground racks of 16 per rack. I have done as you suggested and placed two racks at 45 degrees from due South. One at 135 degrees SE and one at 225 degrees SW. The remaining two are due south. All have an azimuth of 36 degrees. The resulting performance is way beyond my expectations, interestingly, the SW panels produce half the power that the SE array produce in the early morning. This must be just from the back side of the SW panels. So pleased I changed my mind and went with the Bifacial panels. I also followed your advice and split the load on each of my two inverters by running racks 1 & 3 to the first and 2 & 4 to the second. I knew nothing about electrics before I embarked on this project, let alone solar!
None of this would have been possible without the education you have given me. The clear and concise way you explain the process has been invaluable. I am in your debt. Keep up the good work.
Regards,
Richard.
Richard, thanks for the encouraging feedback! I love that you have taken all the things I've learned from my install and analysis and made a much better solution than I did for my original install. I'm so glad my information could make a difference for you!!
Cover sheets of plywood with reflective Mylar and arrange them low behind the bifacial panels to see how much more power it can generate.
Cement board won't rot
Best Buy a s*** ton of emergency blankets that are cheap as s***. Cover the ground in the back of the panel🤔
Hey Dave! Great video. I'm in New Mexico and I know a guy who did a neat trick with his bifacials. He mounted them as a pergola roof about 15 feet up. And on the ground he put down white concrete unnder the panels and white gravel 20 feet out from the panels. He said he saw a notable increase when he added it.
Nice idea! Thanks for posting.
I picked manderins years ago ,and they had a white geo-textile pinned under the trees specifically to reflect light to the underside of the trees - and help the fruit rupen quicker , same thing really ..
Wether you'd want thousands of acres of plastic fabric everywhere is another issue though ..
If the PVs were on a slanted mount on top of a roof I imagine colouring the roof white would increase panel efficiency AND cool the building.
Thank you for another great video. I am installing a ground mount system right now. One thing you did not mention was Bifacial racking, I managed to change my order for racks that are specifically designed for Bifacial and have no supports crossing the back of the panel. They adjust to the panel size. I was also able to get new Longi 445W Bifacial panels for only a few €’s more than the same watt standard panels. Interestingly, the Bifacial come with a 30 year performance warranty as opposed to the standard Longi panels 25 years.
Thanks, good point! I did forget to mention the racking considerations. I think they can offer a longer warranty because they start at a much higher output with the backside boost and the backside glass is a better material then the typical back sheet.
I've had my bifacials installed on our offgrid property for a little over 6 months, I'm getting much better performance than I expected.
That was the most comprehensive presentation I've ever seen! Although I'm not that great at math, I understood your explanation perfectly. Well done sir!
Thanks! Glad it was helpful!
should lay your bifacials on there side. keep panels a little more vertical and step each row back the width of panel.[like a set of stairs] you should get a reflection from front of second and third rows plus less snow in winter. would be nice to see thanks. make your stand a just forward or back for summer or winter
Outstanding content. Conclusions on bi-facial panels I've had to piece together from a myriad of sources...almost all confirmed in one video.
I think the only belief not specifically confirmed has to do with backside gain being able to heat panels enough to shed snow cover on the top side from the heat produced by power generation entirely from the back side. Ground-mount panels set to a steep winter angle for a lower sun should automatically shed snow early in the day and provide substantially more power than panels with cells only exposed to light from the snow-covered top side - all with no manual snow removal activity.
Thanks! Yes, come winter I will have results on snow, steeper angels and roof installations.
To get more benefit from the backside of the bifacial panels, you could apply something shiney ( foil on foam, foil tape, etc ) and mount it on plywood. Then install the plywood behind the bifacial panel mounting rack so that at peak sun reflection, the plywood+foil sun reflection hits back side of the bifacial panels.
I use twin 3120 watt bifacial arrays on dual axis trackers and during the summer I maxed out at just under 6700 watts. I placed the white granite rocks under my panels in order to catch as much reflection as possible plus my panels are elevated so I get reflective light from all angles.
Nice! What tracker do you use?
@@ProjectsWithDave I built them myself out of 4” drill stem, cost around $1,000 including the electronics.
Cool! Sounds like a great project!
It's nice to see an actual in depth comparison of bifacial to standard panels. I too live in ohio and plan on doing solar at home but im waiting on the paperwork side of things and ive missed out on panels and inverters so far because of it. But my plan is now to get 20 445watt canadian bifacials, two sungoldpower sp6548 inverters, 30kwh eg4 lifepower4 to run my whole house. The array is going to be mounted at 45° because i have a friend right down the road and he gets the best all around output at that angle and it should shed snow decent. Im going to have ac input with the inverters if/when my solar cant run the whole house in the summer bc the 3 ton ac unit. I use around 45-60kwh a day(summer) so im guessing it'll handle it.
I think the steeper angle is a good choice to maximize winter production. However, if your max consumption is in the summer, you may want to go with 30 or 40deg.
For best radiance, make sure the reflective material is curved [to gather more IR] and farther away from the back of panel.
Ideal IR would be a hemi-spherical 'cup' that will be focused towards the center of the array.
IR is waste in these types of panels - we want the visible spectrum. IR actually inhibits performance.
Excellent explanation!❤. Now I have made my mind to go with bifacial. greetings from Pakistan
Thank you for the insight. Im thinking about putting high quality reflector under my 400watt bifacial solar panel. Can you demonstrate this technique and show the difference, if any. 🤩 THX.
Yes, data coming soon.
I used Canadian Solar 440 bifacials and put them above a galvalume metal building (low slope) roof, with a racking system that allows me to tilt up for winter, and down for summer, in both cases my panels are well above the metal roof. Being near the 49th parallel, the panels have sun Behind them for a good stretch of the year, and lots of reflection during winter. My best production ever is acturally January and February when it is cold, and lots of reflection from snow and metal roofing. Yeah those high production numbers are only for a few hours per day, but when you need every watt, this is important. I have seen over 115% of rated capacity on many sunny cold days.
One thing to be careful with - Put your framing only inline with the panel edges: no strut running in the middle of the PV back side! keep all the wires and any conduit or wire way away from anywhere they can cause shadows!
Thanks for posting your actual experience!
You should do a video between micro investors, optimizers, and 1 charger/installer that you put in the house . Would love to know which one performs the best and gives you the best efficiency
I already have plans to do a back to back comparison with NEP Micro inverters and the SolarEdge optimizer system in the future.
How are they performing in the snow? Are you getting a lot of reflective light?
Great video Dave! A lot of helpful info here, especially for someone new trying to decide what works best for them.
Thanks! Glad it was helpful!
What about a reflective insulation foam board, with an air gap to let the heat out?
Yes I had an idea as soon as I heard about by facial solar panels
They make a paint that is so white. It actually keeps the surface underneath it 15° cooler than ambient temperature
So simply paint the concrete slab underneath your solar panels with that ultra white paint and you would probably get a copious amount of bounce back
So one thing I read somewhere is that you should consider increasing the tilt angle from the ideal at your latitude by 5 - 8 degrees and also raise the mounts as high as you can. They also said that you should increase the ground area below the back of the panels you cover with something reflective, like white stones.
Since the power boost is going to have the biggest increase in mid summer it makes sense to adjust the tilt angle to favor winter production, that would result in a more even production throughout the year. Another advantage of bifacial! If you have a link to the information you read feel free to post it here. Thanks!
What about water for the reflective back surface?
I wish you would have tried them with white metal roofing under them. We are building a net zero condo with a 3-12 pitch white metal standing seem roof. I'd like to try them.
I did! You can watch the video here: ruclips.net/video/mzqjCsZKUYQ/видео.html
It would be interesting to cover the ground with aluminum foil to see if it would reflect better than light-colored rocks.
I do have bifacials with white planes sheets under. They work 3 times better Then my Dad,s standard.
Nice! In every test I run they seem to do better. It's a game changer in solar technology.
Thanks for doing this research! It is interesting with bi-facial, half-cell, different bus bar designs, and microinveters how much better panels are with shade and how much more real efficiency they show. Those NEP 600s are clipped at 390W per PV input, you may have had more! I am looking at doing a similar system with AP Systems DS3s and the Aptos 440w bifacial from Signature Solar, which also may experience clipping! The one thing that I am still trying to figure out is racking, do you like your Ready Rack system? Would you have gone with this system if you were doing things over again? I'm looking to do a ground mount with 30 72-cell panels, I would love to have it seasonally adjustable tilt and don't care about aesthetics. However, it seems like tilt adds too much money and these static mounts are likely going to be the best bet.
I do like my racking system and I would go with it again. There is a single pole system with manual tilt adjustment one of my friends is installing that would do what you want, but it requires special equipment to drive the posts so it would be more expensive. I only connected one panel to each NEP microinverter so there was no clipping in my results. The BDM600X is capable of 580W output per inverter. I got the same result from the microinverter and the optimizers.
Great description and analysis. Considering these to refurb my ground mounted system. Season tilt for Lat 50 means they are almost vertical, slight hill and snow behind the panels would mean quiet a boost. Also -40'c has significant effect, watch out for your Voc Max!
Sounds like a good application for bifacials.
You're channel is so underrated
Be interesting to see if the BiFacial panels shed snow quicker since they're likely to heat up quicker in lower light conditions.
I'm also very curious, I'll let you know when I get the results.
@@ProjectsWithDave any updates ?
@@ProjectsWithDave Yeah, I'm curious if the perform better in winter months too when they can get more light underneath from reflected snow. I live in Illinois, so really wind power would be a better option, but solar is going to be easier of an install and serve as an awning of sorts too.
In India bifacial solar price is Rs.24.30 or $0.28 per watt . With free home delivery service
Wow, that's a great deal!
@@ProjectsWithDave yaa bro 👍🏻😉 . (Waaree solar company)
Bifacials are highly recommended when installed on flat rooftops without tiles painted white and always installed on angle (this is the case for many buildings in southern Europe). They are very efficient when the surface behind them is reflective.
I imagine that would be much better than mounted flat on a roof, but it would require more racking equipment to achieve that.
@@ProjectsWithDave In that case you stick with the normal half cut, mono PV. I mean, if racking costs double the money just to put some bifacials, it's better to avoid them. Watching your video experiment regarding panel orientation, I'm thinking of using a couple of big power output bifacials in EAST-WEST direction for harnessing sun early in the morning and late in the evening, especially during winter. That's I think is a more appropriate and efficient way to use these panels if you can't install them the right way.
Based on my most recent analysis, I think the best orientation would be SSE and SSW. You can see those results here: ruclips.net/video/J7xnY84Ch1E/видео.html
@@ProjectsWithDave Yup, I know...
Man you must be super happy with yourself for producing such monster Size boys at the very least man KUDOS to you I would be and I have 10 410w bi Facial panels from signature solar I’m drawing a blank right now on the manufacture name but I have yet to mount them so when I seen this title I had to watch this asap thank you so much for taking the time to make these awesome info packed GEMs 💎 that anyone thinking about doing solar for themselves or others can’t go wrong starting with your content
Thanks, I appreciate that! It is a lot of work to take all the data and produce meaningful results, so I'm glad it was helpful for you.
GREAT video. I am in the process of upgrading two of my arrays to Q-Cell 480w bifacial panels. I have one array done and can say the performance of bifacial has def improved vs my older Renogy 100w panels...esp in low light (cloudy conditions). My arrays are all ground mounted.
Yes, I think the cloudy performance is the best selling point. Those are the times when you need the boost.
I just added 13kw of q cell 480w bf to my offgrid system they are great panels. 36kw of pv now
Harmony Estates
what then is the drawback for bifacial (except for slightly more weight)? i checked two stores, they sell bifacial as much as the normal panel.
They have short leads, so if you are not using a string inverter you may have to make lots of MC4 extension cords. Otherwise I have found them to be superior in almost every other way.
@@ProjectsWithDave thanks!
Thank You for All that you are doing for our Planet Earth.... Peace.. Shalom.. Salam.. Namaste .. 🙏🏻 😊 🌈 ✌ 🌷 ☮ ❤🕊
How about a reflective surface laying flat or at an angle reflecting sunlight back towards the back of the panels.
In fact it might even work top side reflecting sunlight that might normally past the top side of panels back towards the panels.
Just found this video so I'm a little late to the party. But, I can attest the Blue Sun 460-bifacial panels are awesome. We put 12 on top of our barn with S5 Protea brackets above very light colored AG panel and the results are incredible. Actually a bit too good to believe. Last weekend, just before peak sun, with only 6 of the panels turned on, our Growatt inverter read it was receiving 122 watts @ 30 amps from the 6 panels. If that's truly the case, we're just over 600w per panel. I need to touch base with Signature Solar to see if that's even possible. Or possibly it's reading incorrectly. Either way, we're generating all the power we need. Thanks for making awesome videos!
Thanks for the feedback! I'm glad they are working well for you. You would not be getting 600W from 460W panels. Probably no more than 529W best case.
My inlaw has a cliff wall in the front yard in the Berkshire mountains.
Im moving there going to put those pannels in front mabe 10' and paint a reflective rock wall. Aney paint recommendations 😮
That’s all doesn’t matter. What are real numbers is a price to watt ratio, internal resistances (direct and back), and a durability of a surface. I’m sure it’s possible to find a 10% less expensive standard panel, or 10% more powerful for a same money. And to use a good mounting, wind proof, etc
Hi Dave Have you tried mounting the Bifacial panels vertically in the North south direction so they get morning sun on one side and evening sun of the other ?
At first thought it doesn't sound intuitively correct but then who who would have thought you would get the results you did with Bifacials.
It would hugely boost early morning and late evening production which is the most useful/useable times of day.
You also get snow in winter which would help with the refection (I'm in KOPU New Zealand and only get a few frosts a year).
Perhaps East West ?? who knows as they are new technology that is allowing a whole plethora of ideas
Yes, I have a test running now with vertical bifacial panels. So far, they have good morning and evening performance and on cloudy days they perform very close to the south facing panels, but overall, they still underperform the south facing 30deg panels.
@@ProjectsWithDave thank you for your reply. Much appreciated
Immediately after I sent that question I 'discovered' alot more information online about them since you did that video 10 months ago and the orrigional German study "Smart Energy" published Aug 2022, where they do vertical bifacial panels to be able to use the ground for other purposes eg agriculture.
There are lots of smart people out there coming up with all sorts of new ways of using things and with the internet to make it accessible it's amazing.
I'm a 70y old ex research scientist (the ex just means no one is paying me now) but we never stop learning.
I like your videos as you measure and calculate stuff in a robust manner that's consumer friendly (a big problem with alot of science).
Virtical bifacial panels over water. Now that's an interesting one. Reflection and cool air, dual use of area for fish farms and dams ?
The permutations are endless
Thank you.
The solar space is fun to be in. As you said you never stop learning, and there is always something new to learn and experiment with when it comes to solar. The combinations are truly endless.... : )
Thanks! I live in the Okanagan, British Columbia, Canada. Orchard growers lay white plastic on the ground between the rows to reflect more light back up at the fruit. Might work for this too when you don’t have snow. I specify high albedo (white) roofing on flat roofs with bifacial solar arrays.
Thanks for the info! The parallels between managing reflected light for both solar production and plant growth is very interesting.
DuPont house wrat available in 9' x 200' rolls. Roll out and stake down under the bifacials. Not as reflective as snow, but it won't cover to top face.
The most obvious solution would be (angled) mirrors under the panels for maximum reflection.
I have read white reflects well also.
I'm planning on dipping my toes in a small off grid system to keep the freezers and computers going and these panes are intriguing as I was thinking of installing them on a galvanized roof of a metal building. The south facing roof pitch is only 2 degrees so I would use a little more tilt on the panels to allow the morning and late afternoon sun to bounce off the shiny roof and onto the back of the panels.
If you plan to elevate the panels off the roof at a diverging angle, I think you will see a noticeable benefit from the reflection. I think you would need 18" to 24" at the back edge to see a significant contribution.
I did just that. My battery pack runs 2 full sized 24 cu ft self defrosting refrigerators, an old 24 cu ft upright freezer and a 5 cu ft chest freezer. I bought the Signature 410 watt bifacial panels last year not knowing what I was doing. I have 4 panels at 40 degree elevation on a roof deck, and another single 410 watt damaged panel on the roof with no back lighting. My sun exposure is far from ideal but better than nothing. In August, they work well from 10AM to 3PM. At this moment I am preparing to install 4 more on the roof. I have aluminum channel mounts and ran into the clamp problem. The panels are 30mm thick and the middle Tee clamps work just fine. The end clamps needed modification to hold tightly. Most clamps are made for 35mm to 50mm frame thickness.
The panels are about 40x80 inches each. I mounted them horizontal lengthwise, 2 rows of 40x160 inches on that 40 degree home built triangulated frame. The low profile won't catch the wind like if the panel was mounted vertically.
I got really good at making MC4 jumper wires after buying the cable kits and with strippers and crimping tool. The gender of + and minus outer sleeves with OPPOSITE gender inside contacts was confusing at first but I can do them in my sleep now. They were clever enough to make sure the internal + and minus crimped contacts are different sizes to make them goof proof. Remember PPP on the solar panel output wire... Panel Prick Positive ...the male end is positive. All solar panel MC-4 female connectors are negative.
My batteries stay between 80% charge and 97% charge so far. That old upright freezer is a real energy pig and runs at about 480 watts. I have 2 chest freezers, 5 and 10 cu ft being tested right now and they run at about 77 watts each, far cry from the 1984 built freezer. Good luck!
installing 530watts*6 Bifacial panels in my indian home now as ongrid. (background is less when they install structure!).
Buy the solar you need now. Prices are cheap but they wont be for long. Bifacial panels when this was made is $200 plus, right now it is $120 for a 400 watt panel.
I have an idea about how to maximize light to both sides of bifacial cell. Put a long cylindrical parabolic mirror underneath the cells. Place cells in a line parallel to the cylindrical parabolic mirror with the back side facing into the mirror, front side directly facing sun. This arrangement allows for rotation of the parabolic mirror with the cells to always face the sun. I bet you could significantly improve performance. There are some challenges to overcome but idea is sound. This technique would also work with regular mono cells with front side facing down. I am working on a prototype so as to get some real values.
Typo ?What would “HAPPEN”…….
I hate these self editing programs !!!
230cad for a 445w panel!!! wow! i'm in Sweden and the one place i know that sells panels charge 593cad for a 360w half cut panel! insane!
Maximizing bifacials ideas: Dolomite gravel as ground cover underneat, in the same fashion: Marble gravel under the panels, both reflect significantly more light from the ground. A even more expensive option is the white reflective paint used for road lines, tumble any rock in a bath of that paint and a highly reflective and durable ground cover will be produced.
I was planing on polished aluminum sheets, but this paint made me re think
The thought of something reflective under the panels is so obvious why was it not tried? What are we missing?
@@tommak6516 only those last 15% or so of extra efficency you can squeeze out of the double sided panels. Been doing some trials for "winter electricity" with 90 degree "standing" panels and reflective white paint on the wall behind them, roughly 1.5 meters distance also the ground 0.5 in front and spacing them with 1.5 panel-width gaps to the next in the row (chucked up 10 of them for testing purposes against a barn wall painted in reflective paint roughly 3m up the wall) Panel size where 2.2mx1.2m (largest bifacials I could find).
@@tommak6516 forgot to mention this is at 56 degrees North latitude, further south this will have to be recalculated for different sun heights ofc.
@@tommak6516 Mirrors are optically grey, so less reflectance than white. Despite the perfect mirror image of coherent light rays, homemade mirrors are less optimal because of potentially damaging lensed specular high lights and unpredictable effect of shadows on current flow. We don't need to boil water here. And even if a perfect mirror would be able to be made cheaply and durably, the panels don't even need to see a perfect 1:1 picture of the sun. White coating is: cheap, can be found in many forms, easier to repair and maintain. This is a missed element.
Half cut should be vs Half cut. Good testing and experimenting but not ideal. Thanx for sharing.
I always recommend bifacial, it gives me more buffer on yearly energy output
Im looking at a simple ground RV install with a simple hinge on one side, a reflective surface on the other and hinged vertical for tilt.Then tilt them to the sun. Im hoping this simple clam shell will support them during storage but I fear the will be getting pretty heavy. I might need slightly smaller panels
are you there sales person.. you should be...
No, but I guess if you make a good product you don't have to pay sales people : )
Is it possible to get a pdf file of the calculated results from the information shown in this video?
It will be interesting if you use mirror on the back of the bi facial panel if you can get full performance from the back of it
I never heard of solar DC optimizer. How do I get it?. To get sun reflect to the back, use a glass and foil at the bottom. Thank me later if it works.
The Mykonos postcards will never be the same once the greeks realise what perfect combo white roofs and bifacial panels are. Come and take your vacation photos before it is to late.
There are no "regular panels" at this stage of the solar industry because there are few, if and, recognized standards in the US.!.!.!.!.
The issues with the pannel thiskness and cable length are a function of the manufacturer, not because they are bi facial .
Aptos makes a bi facial with standard thickness and 1 meter cables, they just cost more than some odd commercial brands .
You have to weigh the cost of cable extentions when pricing pannels , as the cabling costs can add up .
NON of this matters. What is the $$$/WAT ? IMO
use white landscaping pebbles to increase ground reflection
Try some white quartz gravel under the bifacial panels
Consider a second solar array behind the first for a reflective surface, for more utilization (suns reflection) of the rear bifacial panel.
You need to fix your graph the %80+ are about %50 graphically
Would it be interesting to test with standing panels so that they get sunlight in the morning from the front andin the evening from the back side? the floor covered with aluminum zinc roof sheets. i could imagine that the output it is more than the normal south direction installation
Two-way Infinity mirror film it's freaking cheap you can wrap it around wood who cares if it gets hit by weather and you can make 4 ft by 8 ft sheets out of OSB board and direct the damn sunlight to it Make it so number one you can get the stuff at Amazon
Put something reflective on the ground behind them, or just paint the ground white. That should increase the irradiance
Too bad you didn't test the down face of this biracial solar panel to its full extent, like with a smooth ultra white ground surface, ground- mounted high enough so that the down face gets reflected light not just from the back but also from the front, maybe try with a mirror film behind the panel to reflect even more light, get a fan under the panel to see if cool air benefits productivity, this kind of tests that come to mind with bifacial. Your huge wooden frame is also a big hindrance for bifacial panels. Better use thin flat metal just under the sides of the panel, so, customized to its size.
And really, you should not even mention rooftop mounting for bifacial, when rooftop panels should be as thin as possible and ideally part of a weatherproof roof design rather than looking like roof warts on top of another roof. That second face won't get used at all, although your blocked face tests show that there is some extra efficiency, possibly because some light that manages to cross the topside gets reflected by the second sheet of glass at the bottom thus converting more electrons, or some other cause that would be interesting to know.
Best thing is with Sun from the back the snow will melt
I'm planning to place aluminium foil sheets for reflecting light for back side.
Do mirror on back side😂, I'm. In Russia Saint-Petersburg
Have you thought about a mirror or a white reflector below your array. An array of mirrors would be a a lone off cost but radiator reflectors would be a good trial an these bifacial panels.
It's a scam. If people say it's a 100-watt panel and its only 80 walls on a best day than it not a 100-watt panel, it's an 80-watt panel. Don't lie to people just say it's an 80-watt panel.
Could you try laying mirrors behind them that are not shaded by the panels and are angled toward the back of the panels.
Maybe try spreading white sand on the ground under your array for back reflection,
Why did you spoil your useful information by using a lie that the price of solar is going up ?
Use plywood on the ground around your array and paint it with the white solar reflective paint
Great Vid thanks for taking the time to give us the great breakdown in real world situations
Thanks! No problem 👍
Um mirrors? To increase photon exposure to backside of panels.
Put mirrors or al foil on back floor and try or just reflective paint .
just low grade white plastic fences from home depot or lowes on ground for reflection
What if you put reflectors behind it?😊
Hi Dave, another great Video, I just received 21 CS 450 WATT panels from Santan, almost had the same unloading problem that you did. The truck driver had a powered pallet jack and almost run it off the back of truck, lucky I had my skid steer with forks and got under the pallet before he dumped it. I am building my own ground mount, and putting up a 31 foot car port and using one side of the verticals of carport structure to attach Unistrut @ 30 degree supports for my mounting rails to attach to . Won't get the best performance on back side, but can't beat the price for panels. Now I am looking for an Inverter, and leaning on using a Growatt 7.6 kw or 10Kw as to not get into clipping hybrid inverter, they seem most reasonable priced and have a battery backup option that can be added latter.
Using panels to serve as a roof and power is a great strategy. If your orientation isn't ideal, you won't likely make much use of the 10kW inverter. You will probably be fine with the 7.6kW.
try a mirrored surface facing the back side of the panel.
It sounds like ground mount is a much better way to get production then rooftop.
How about trying some reflective materials underneath the bifacials?
Reflectors or mirrors.
I plan to try a white steel roof later this summer. Mirrors would likely be helpful, but delicate and hard to position. I was thinking mounting with a pond backdrop might offer good reflection.
Build near waters edge or over water, that will give you more reflection.
If you install the panels over water you will have a significant increase.
I live above Loch Ness in Scotland and am currently building a house to rent out on my property, which I bought with planning for 3 houses. I have heard about bifacial panels and am going to buy some for my house, which I hope will run on solar power. I am going to put some kind of reflective material on the ground beneath the panels. Can't see why this wouldn't work! But maybe I'm wrong here..............
I ran a test a few days ago with reflectors for my vertical panels I will publish that most likely in August. You can get some idea of the increase in performance from reflection from this video with reflection off the snow: ruclips.net/video/YZWeCUzu0yQ/видео.html
@2:55 and THAT is one of the most common ways to LIE with STATISTICS. Graphs that zoom in on the end to magnify the difference. "you can clearly see just how much..." yeah... The only reason you can "clearly see" the difference is because you're not showing 75% of the graph, where they're THE SAME.
Thanks for your feedback. Dropping the bottom of a graph is not lying with statics. It is a common way to make the delta more visible. The scale on the side hasn't changed. Clearly you were able to understand the magnitude of the difference. My goal is to always show the actual data in as clear a manner as possible. I have no agenda or reason to try and show something that isn't true.
Can you try setting up a test with some type of reflector.. Like outdoor aluminum theremal insulation, white acrylic roof costing or cool metals roofing under the panel.. It might work great on flat roof in my opinion
I'm currently testing on a white metal roof. Results will come in a few months.
great video
Thanks!
Im wondering about the comparison between a standard panel that have a cooling system in the back vs bifacials. As we know, heat decreases panel efficiency.
I would guess a cooling system would cost much more for the boost in performance than the cost of bifacial panels or even just adding more standard panels.
I know this video is a year old, but if you're still looking for something highly reflective there's this grow film called Orca film. 94% reflective, 99% diffusion. Might be worth looking into.
Thanks!
What would harm putting mirrors (stainless steel) on the ground reflecting sun hitting them directly an reflecting up onto the back of theses BIFACIAL panels?… INCREASED production (A LOT), right ?
Based on my winter results, I don't think the cost would be justified. You can see the results from the reflected snow in this video: ruclips.net/video/YZWeCUzu0yQ/видео.html
maybe you can use some aluminum plates to refract the sunlight
How about putting a mirror or a sheet covered with tin foil
One can use mirror to reflect light on the back of the solar panels.