If you find this content helpful, consider using my affiliate links or sending a Super Thanks! Add future content suggestions below Thank You! SunGold Power Bifacial Solar Panels Affiliate Link: sungoldpower.com/collections/bifacial-solar-panels?ref=Projects%20With%20Everyday%20Dave Find Bifacial Solar Panel sources and discounts on my website: projectswithdave.com/solar-panels/ US made Sirius Bifacial Solar Panels: signaturesolar.com/12-87kw-pallet-sirius-pv-415w-bifacial-solar-panel-assembled-in-texas-elnsm54m-hc-415-up-to-539w-with-bifacial-gain-full-pallet-31-solar-panels-12-87kw-total-pallet/?ref=SALE Signature Solar ($50 off $500 or more discount Code "EVERYDAYDAVE"): signaturesolar.com/shop-all/solar-panels/?ref=SALE See more projects and get my FREE Solar Financial Calculator on my website ProjectsWithDave.com: projectswithdave.com/
I have noticed a significant difference in performance in snowy conditions with bifacial panels. You can see some results in this video: th-cam.com/video/YZWeCUzu0yQ/w-d-xo.html
Letting a bit of light through the panel could also be good if you wanna grow anything under them. It would block most of the really harsh sun while still allowing some sunlight through.
Great data and experiments ! What would be interesting is a similar experiment to determine true back-side contribution by blocking out the front of the panel with aluminum foil or whatnot, so that the actual rear contribution can be measured (along with your earlier modifications to the ground reflectivity). While some may think this is information overload, those of us who understand everything you are doing here are your true fans and are here *specifically* because of your rigorous scientific methods beyond what most anyone else on TH-cam is doing. Keep up the amazing work !
I would like to see results with a V-shaped N-S bifacial mount. Put reflector flat on the ground underneath, or maybe even tilted downward. Reflector is cheap, so there is no reason not to extend it well beyond the footprint of the panels. My expectation is a much flatter performance curve throughout the day: Early morning, the bottom side of one arm collects morning sun. Later in the morning the reflector kicks in; a little later, the afternoon-side arm too. Noon, both front sides are producing well. Afternoon is a reverse of morning. Of course the angle of the V needs tuning; I would start at 60 degrees. I liked your idea of using specular-reflective material to spread out the reflection. You could get significant backside collection even at noon.
Your trailer jack leg as the adjustable angle degree is great idea. I've seen this before and like seeing people be creative in winning problems. nice job Dave.
Great video Dave. Remember that the panels typically have a temp coefficient for both voltage and current, so your decrease in watts are pretty much spot on 👍🏼
Been thinking, possibly small fans or cooling system, can cool down the solar panels with re-made reconstructed bracket, with your reflector film, can contain more projectional output and cooling for less degrade from the cells. Just amazing ideas: Projects with Everyday Dave. lots of pontential.
What About Cooper Tubing for heat transfer with possible solution like liquid nitrogen or a cool mini fan to transfer the cooling effect or even water cooling for solar panels..
13:15 use mirrors to guide sunlight to the back panel, then set up some fans along the edge of the test panel to blow wind ACROSS the backside of the panel to keep the temps down.
I had used there Insta Flash Mount's on about 10 solar jobs, they work great. I use them on "flat" roofs as we as compost. the price for the "kit" cannot be beat for what you get.
That's great to hear, I'm glad you've had good experience with them. I'm curious what the long term durability will be for the soft sealant. How long have the systems been installed? Any leaks?
Very nice experimental results! That took a lot of work but I love the irradiance and temperature correlations. I've been specing out my DIY expansion project on a few bulk solar panel wholesalers and I was surprised to find so many bifacial and half-cut panels. Far more than were available two years ago. And indeed, prices are very similar between non-bifacial and bifacial panels for larger panels (400W+). Below 400W non-bifacial panels seem to be discounted far more heavily. There are some great prices out there. I've been scoping out the Hyundai 400W+ panels (dimensions fit my roof better than most of the other brands). Like the HiS-S410YH(BK)'s. -Matt
The options have improved dramatically over the past several years. It would take a significant discount for me to consider non-bifacial panels for a ground mount system. Bifacial panels have a significant advantage in cloudy weather when you need the power the most.
For bifacial panels I have seen older data (3+ years ago) suggesting using a minimum elevation of the front bottom panel edge of at least 42" and having minimal obstructions that reduced the light from reflecting off the ground under the panels. Having a reflective covering on the ground helps tremendously too. Racking that supports the panels on the long edge is far more efficient than using the conventional two tracks running the short way and blocking the rear. I would have liked to find a way to send you a photo of an (prototype) edge mounted Canadian Solar install.
I bought some Talesun 400w bi-facial panels that have no glass on the back. back in February 2024 signature solar had a sale for 25cent a watt on these panels before tariffs hit.
Have you tried vertical panel cooling via running pumped water over both sides of the panel? You could have a reservoir under the panel and keep pumping water back up to the top and letting it flow down both sides. I bet this scales well if the same pump is cooling more panels at once, lowering the pump's power cost by distributing it over more panels.
Good stuff. You might try a simple misting system with or without a fan on the backside or frontside. I use a similar system for my AC to cool the condenser and it saves a considerable amount of power over the season. I have it automatically come on with s hall sensor/ss relay. Apparently this sort of thing is quite common is the southern US as AC units run pretty much continuously.
@ProjectsWithDave yes I use a mineral filter that I replace every year. It doesn't really use very much water, doesn't make a dent in my water usage bill. I use the water from my RO water filter for my garden. Suppose I could use that for the mist but the cost is not prohibitive so ya works great.
Thanks for doing this experiment. I Just installed by facial panels on a ground mount system with Tesla batteries. They are working beautifully. I wonder what they’re gonna do in the snow.
Although performance in the winter is much less than the summer, I know from experience you will get more power in the snow than you would be getting with standard panels. You can see some results in this video: th-cam.com/video/YZWeCUzu0yQ/w-d-xo.html
Awesome. Dave, thank you. This is exactly what I personally was asking for under one of your previous videos! You content is amazing and super helpful.
Thank you for this its really a very interesting and well executed testing process. I wonder if I could suggest a test query? In the United Kingdom we are seeing more bifacial panels being recommended and installed on Residential Roofs. Most roofs in the UK are a brown/terracotta Tile, grey concrete tile or natural Slate and the panels are installed at a distance around 6 inches from the roof. With the low "albido" effect of the roof substrate would it be possible to test your setup with both panels face up and with one with a backing placed about 6" from the panel? Backing consisting of something like roofing felt or similar low reflective surface?
Just a note about your performance summary at 12:00. Despite blocking the rear of the face up and face down panels the solar cells still allow light to pass through and some of this is picked up by the rear cells. From there all your stats are affected by this element. Assuming the two panels are exactly the same it would be more accurate to calculate the difference between face up @ 402W minus face down @ 254W and equate the difference of 148W (32%) as being the measurement of the benefit of the bifaciality. Unfortunately this is still only an approximation but certainly closer. This would give a "Theoretical Maximum" of 460W Rated + 148W Bifacial = 508W
I used black plastic on the cardboard blockers, and the blockers are placed against the glass. I think very little light is reflected back Bifacial panels placed close to a dark color roof, will give you very little gain. However, bifacial panels are not much more expensive and you don't have to worry about back sheet failures.
It would be a neat experiment to first run the cold water line, that goes to your water heater, through water pipes attached to a solar array for cooling them down. Would probably be better with non-bifacial panels so you can turn the backs into heat sinks. I wonder if the added cost would be worth it considering a reduction of power required for the water heater plus the increased productivity of the array. If you live in an area with water towers you don’t have to power the water flow, so the only expense is the heatsink mechanism and pipes.
There are systems that are designed to do that. I haven't run the math, but I suspect it would be hard to justify the added cost for the additional equipment.
Most panels have side to side mounting. Put a gap of 20% of panel width to allow more sunlight to get through to a white metal roof. Say 160mm. The gap may allow more cooling air flow. 😎 Many rooftop systems are on part of the roof, bunched together. Shorter mounting rails and fewer clamps and quicker to install. Sunlight on the metal below may increase heating below panels. So, temperature readings are needed. I am thinking of a sloping roof, a 100mm gap between panel and sloping metal roof. Also, would a forced airflow below the panel help keep the panels cool mid summer heat waves. ?????
13:19 - yes, it can work easily: mount the panel on the ground like you did, but only a stand for just 1 panel only Then use a foil to create a pond around and under the panel, but it needs big pond and not just 2 m around . If you have a wet acre somewhere else with a pond or so build it there and do the tests with a battery and solar charge controller. But, and there is a big but: be aware that the usual 3 diodes in those boxes somewhere on the back are NOT rated for this usecase . We have burned the panel through on the lake just 5 m from the waterline away. First it did not work that well and we forgot about the test that day. Next evening after the harvest was done that panel was dead and the diodeboxes had melted into whatever. Not sure if there were further damages cause it ended in the scrapyard. We tried that 2 years ago or so. Back then we had only 1 panel left and that was the end of our test period.
Usually you should get slightly over rated power from a panel when new? Rating is guaranteed for a number of years, which means they have to perform above specs when new. I usually measure 104-105% from a new panel.
@@ProjectsWithDave At what you should get on any clear day with a reasonable solar height. Can be more than 1000W per sqm. You get a solar panel, unpack it point it perpendicular to the sun and load it at the claimed amps on the sticker on the backside. There is no solar business tradition of overrating panels. If it is not delivering the nameplate power out of the box, it is faulty. Preferably should deliver a few percent more than nameplate power to be able to deliver the guaranteed power for the number of years stated in the warranty. UL 1703 certification specifies power rating and degradation.
Good Video Dave! What is the weight difference between equal size bi facial & mono facial panels? You mentioned glass on the back side of the bi facial in the beginning of the video. When doing some simple math on glass weight, I come up with the bi facial possibly weighing 26 more pounds per panel over a mono facial. The reason I bring this up is because of the added weight to an older roof. This may not sound like much but when combined with high winds (such as Santa Ana winds in So Cal) this could be significant. Just think out loud here. Cheers
Yes, bifacial panels are much heaver. Not just a consideration for weight on the roof, but they are also more work to install. Also, you won't see a significant benefit with bifacial panels on a roof.
13:24 Make cheep mirrors by gluing mylar survival blankets to plywood, and set up a mirror array behind your solar panel array angled more steeply to reflect sunlight back under to the back face. Might not be *full* sun, but it’d be close. I would think that anyone living in a snowy environment would benefit the most from bifacial panels in the winter, with the shorter days, and reflective environment.
I really want to know what you guys are doing for ground Mount arrays for these bifacial panels I would really like to see some good comparisons between panels higher up in the air or closer to the ground according to this video i believe you just said that the panels perform better closer to the reflective surface like maybe marble chips white rubber roof tin a mirror or a reflective surface such as aluminum foil or maybe a old solar pool cover. What's everyone using for really cost-effective ground mounts that works the best for bifacials that are 400 + watts
I appreciate the conscientious data collection and analysis. Did I miss the part where you directly measured front and back working together (rather than blocked back and adding front and back separately). Nobody installs these with blocking on the back.
Great Video again. You never fail to impress. Question: if I had 10 panels facing Southeast and 10 panels facing Southwest (and don’t have micro inverters or optimizers) can I (and should I) connect some SE panels in parallel (or series) with some SW panels? Or should the SE panels be on a completely different string than the SW panels and be connected to a different MPPT?
You should make them separate strings connected to separate MPPT inputs. 20 panels would produce a voltage that was too high for most inventers anyway.
Wondering if the addition of small DC fans would be worth the trouble. I did a few calculations based on data here and guesses if the fans were very low cost them probably yes depending on how effective the cooling and longevity of the fans. If I can do it on the cheap I may try an experiment on one of my 3 arrays
You think you have it bad? My panels hit 70+C after a long hot day at 130PM. I guessed as much as I was designing the system so I specified 600w to 440w microinverters with a DC to AC of 1.38 in order to eliminate as much of the loss as possible. Doing so also allows me to hit peak at around 800w/m2.
Sounds like you did some planning to account for your weather conditions. People don't realize there is no one-size-fits-all solution when it comes to solar.
Hi Dave, I had a solar power system installed on my roof last year and am planning on expanding it with some bifacial panels. I have pretty much filled up the south facing part of my roof so the new array will have to go on the north facing side. It is a standing seam metal roof and is only sloped about 10°. I am wondering if it is worth putting the new panels on a rack mount that will get them up to the optimum angle for my area (San Antonio, TX), which is about 30°. That would mean mounting them at a 40° angle from that part of the roof. I also figure that will help get more light to the backside of bifacial panels. What do you think?
38* as max angle.. seems shallow for Canada That actually needs 45-50* plus 11* (adjustable) at the border areas.. and I'd only se bifacials on a tracking mount with a white background (roof or stone base (and no weeds)
Just wondering: if you did have a means of actively cooling a panel, as alluded to, why not direct additional sunlight through the front of the panel, rather than perhaps awkwardly directing it through the back side (i.e., towards the sun) in addition to through the front?
I wonder what would happen if you had a VERY white reflective panel behind these maybe 2 inches deep to defuse and reflect all the light let in between them to the back of the panel.
Hi Dave ! From your experience, solar tracker combined with bifacials that have a white / aluminium panel at aprox 50-70 cm distance, can produce the max from a PV system ?
I think you are right, but I don't know how to prove it definitively. It would take some kind of elaborate mirror system. I don't think I can do it justice. But who knows, I might try it some day just out of curiosity.
From the datasheet, the electrical parameter of the solar module is tested at STC condition, 1000W/m2 irradiance, 25 degreeC Cell temperature, 1.5 air mass. Any changes in the environment will affect the energy generation.
Hm, at 10 pannels these sre still 200$ a pop. Only worth it if you're really needing high energy density array. I think theres some 450- 500w panels for half that.
So with 1000 W/m2 irradiance the output is about 360 W. What is the panel efficiency then? I'm asking because you don't mention how much power each m2 of panel generates. Not sure, but when you show the graph when at minus 10-20 Celsius the efficiency is over 100% of nominal, you are talking about panel temperature, not air temperature. And when you have a very sunny day the panels will heat up to maybe 0 Celsius, or more. Finally, this increased output will affect only the situation when it's much colder and the wind is cooling panels down. Otherwise, it will take place only in the beginning of the cycle of very sunny day. With little sunshine the gain will be to small.
@@ProjectsWithDave maybe I missed something, but how 1 m2 can produce 400 W? It's close to the total panel output, with the surface close to almost 2 m2. PS You have a great channel, and a true talent for experimentation. I didn't finish my book on solar (maybe I will one day) - on main key topics, in big part for grid-level projects, economics, ecology and so on - but I wish I were watching your channel when I started, so many things are shown, not just described. Good luck!
@@денисбаженов-щ1б 3:00, the packaging shows SG-460WBG, google the datasheet. The Pmax @ STC is 460W, Dimension - 1994x1198mm, efficiency 19.3%. If you are too lazy to calculate or google it. Take note to account for that 2% reduction in power due to LID for modules using monocrystalline perc technology
I don't think the cost for these is justified based on very little return from the backside of the panel. I guess someone that had very limited roof space might benefit a little from them. These things are expensive.
I'd write about the 'How to make your own solar reflective paint' that reflects at the frequencies used by panels, but I know the comments never get read and you content creators only say "comment" to please The Algorithm. So no: DON'T look into it. And you just got another algorithm pleasing comment. Bully for you!
there is no dramatic increase in performanse rhe full video is nonsens. yes the make ~5% more if the panels are lift 2 meters over the groud in the air, aree this 5% importand onm any way if to get this is confusing stuff to do important??? no
🤨You need a lot more knowledge of physics, where the technology itself comes from. And with cheap thinking, cheap tests, your results are nothing, which you actually prove. The bad thing is that you expose people to things that you are not sure about, due to lack of knowledge. Joker: It's not about cables and electricity, which you understand more or less. But, you're on the right track. Keep going. Think about where you are wrong.
If you find this content helpful, consider using my affiliate links or sending a Super Thanks! Add future content suggestions below Thank You!
SunGold Power Bifacial Solar Panels Affiliate Link: sungoldpower.com/collections/bifacial-solar-panels?ref=Projects%20With%20Everyday%20Dave
Find Bifacial Solar Panel sources and discounts on my website: projectswithdave.com/solar-panels/
US made Sirius Bifacial Solar Panels: signaturesolar.com/12-87kw-pallet-sirius-pv-415w-bifacial-solar-panel-assembled-in-texas-elnsm54m-hc-415-up-to-539w-with-bifacial-gain-full-pallet-31-solar-panels-12-87kw-total-pallet/?ref=SALE
Signature Solar ($50 off $500 or more discount Code "EVERYDAYDAVE"): signaturesolar.com/shop-all/solar-panels/?ref=SALE
See more projects and get my FREE Solar Financial Calculator on my website ProjectsWithDave.com: projectswithdave.com/
Bifacial are awesome in the snow. In winter the combination of the cold and the extra watts makes up a little of the shorter/cloudier days.
I have noticed a significant difference in performance in snowy conditions with bifacial panels. You can see some results in this video: th-cam.com/video/YZWeCUzu0yQ/w-d-xo.html
Great analysis. I have a JA SOLAR 575W panel pifacial and I get 600W for 4 hours from 10am to 3pm.
So the total is 600W * 4 = 2400 ?
@dwicahyoariswinarto Yes..today I added the third panel and got 1930W from 9:30Am to 3pm
@@alimiran81 wow thats pretty cool you got more than written in spec.
575*3 = 1725
1930-1725 = 205
205/1725*100 = 11.88% more power
Letting a bit of light through the panel could also be good if you wanna grow anything under them. It would block most of the really harsh sun while still allowing some sunlight through.
Right! I think it would be great for some alternating glass/solar roof panels on a greenhouse.
Great point. Thanks
Great data and experiments ! What would be interesting is a similar experiment to determine true back-side contribution by blocking out the front of the panel with aluminum foil or whatnot, so that the actual rear contribution can be measured (along with your earlier modifications to the ground reflectivity). While some may think this is information overload, those of us who understand everything you are doing here are your true fans and are here *specifically* because of your rigorous scientific methods beyond what most anyone else on TH-cam is doing. Keep up the amazing work !
I would like to see results with a V-shaped N-S bifacial mount. Put reflector flat on the ground underneath, or maybe even tilted downward. Reflector is cheap, so there is no reason not to extend it well beyond the footprint of the panels. My expectation is a much flatter performance curve throughout the day: Early morning, the bottom side of one arm collects morning sun. Later in the morning the reflector kicks in; a little later, the afternoon-side arm too. Noon, both front sides are producing well. Afternoon is a reverse of morning. Of course the angle of the V needs tuning; I would start at 60 degrees.
I liked your idea of using specular-reflective material to spread out the reflection. You could get significant backside collection even at noon.
Your trailer jack leg as the adjustable angle degree is great idea.
I've seen this before and like seeing people be creative in winning problems.
nice job Dave.
You have a really good channel. Thank you.
Thanks! I am glad you find the content helpful.
Wow this was an amazing set of tests. Got my subscribe for sure.
Great video Dave. Remember that the panels typically have a temp coefficient for both voltage and current, so your decrease in watts are pretty much spot on 👍🏼
Been thinking, possibly small fans or cooling system, can cool down the solar panels with re-made reconstructed bracket, with your reflector film, can contain more projectional output and cooling for less degrade from the cells. Just amazing ideas: Projects with Everyday Dave. lots of pontential.
The amount of used energy to cool down the panel won't be enough to cover the additional energy gained due to lower cell temp.
What About Cooper Tubing for heat transfer with possible solution like liquid nitrogen or a cool mini fan to transfer the cooling effect or even water cooling for solar panels..
13:15 use mirrors to guide sunlight to the back panel, then set up some fans along the edge of the test panel to blow wind ACROSS the backside of the panel to keep the temps down.
I had used there Insta Flash Mount's on about 10 solar jobs, they work great. I use them on "flat" roofs as we as compost. the price for the "kit" cannot be beat for what you get.
That's great to hear, I'm glad you've had good experience with them. I'm curious what the long term durability will be for the soft sealant. How long have the systems been installed? Any leaks?
@@ProjectsWithDave I'm curious what the long term durability will be for the soft sealant as well!
Thanks 👍 🎉 it amazes me that people are still assembling ground mounts using mono facial panels 🤔
It's not just the improvement in performance, but you don't have to worry about all the possible issues that come with failed back sheets.
Very nice experimental results! That took a lot of work but I love the irradiance and temperature correlations. I've been specing out my DIY expansion project on a few bulk solar panel wholesalers and I was surprised to find so many bifacial and half-cut panels. Far more than were available two years ago.
And indeed, prices are very similar between non-bifacial and bifacial panels for larger panels (400W+). Below 400W non-bifacial panels seem to be discounted far more heavily. There are some great prices out there.
I've been scoping out the Hyundai 400W+ panels (dimensions fit my roof better than most of the other brands). Like the HiS-S410YH(BK)'s.
-Matt
The options have improved dramatically over the past several years. It would take a significant discount for me to consider non-bifacial panels for a ground mount system. Bifacial panels have a significant advantage in cloudy weather when you need the power the most.
For bifacial panels I have seen older data (3+ years ago) suggesting using a minimum elevation of the front bottom panel edge of at least 42" and having minimal obstructions that reduced the light from reflecting off the ground under the panels. Having a reflective covering on the ground helps tremendously too. Racking that supports the panels on the long edge is far more efficient than using the conventional two tracks running the short way and blocking the rear. I would have liked to find a way to send you a photo of an (prototype) edge mounted Canadian Solar install.
You can get ahold of me to send a photo through my website here: projectswithdave.com/projectswithdave.com/about/
You're giving 1000wh information to my 100wh brain lol.. Overload 🤯
😂
I bought some Talesun 400w bi-facial panels that have no glass on the back.
back in February 2024 signature solar had a sale for 25cent a watt on these panels before tariffs hit.
That's a great deal! Cheaper than used panels.
Have you tried vertical panel cooling via running pumped water over both sides of the panel? You could have a reservoir under the panel and keep pumping water back up to the top and letting it flow down both sides. I bet this scales well if the same pump is cooling more panels at once, lowering the pump's power cost by distributing it over more panels.
Good stuff. You might try a simple misting system with or without a fan on the backside or frontside. I use a similar system for my AC to cool the condenser and it saves a considerable amount of power over the season. I have it automatically come on with s hall sensor/ss relay. Apparently this sort of thing is quite common is the southern US as AC units run pretty much continuously.
You would need to have mineral free water for that or you would end up with a haze on the panels over time. Do you use the runoff to water the garden?
@ProjectsWithDave yes I use a mineral filter that I replace every year. It doesn't really use very much water, doesn't make a dent in my water usage bill. I use the water from my RO water filter for my garden. Suppose I could use that for the mist but the cost is not prohibitive so ya works great.
Thanks for doing this experiment. I Just installed by facial panels on a ground mount system with Tesla batteries. They are working beautifully. I wonder what they’re gonna do in the snow.
Although performance in the winter is much less than the summer, I know from experience you will get more power in the snow than you would be getting with standard panels. You can see some results in this video: th-cam.com/video/YZWeCUzu0yQ/w-d-xo.html
Awesome. Dave, thank you. This is exactly what I personally was asking for under one of your previous videos! You content is amazing and super helpful.
Thanks, I'm glad you found it useful! I do listen to the request in the comments. I can't do them all, but I do what I can.
Thank you for this its really a very interesting and well executed testing process.
I wonder if I could suggest a test query?
In the United Kingdom we are seeing more bifacial panels being recommended and installed on Residential Roofs.
Most roofs in the UK are a brown/terracotta Tile, grey concrete tile or natural Slate and the panels are installed at a distance around 6 inches from the roof.
With the low "albido" effect of the roof substrate would it be possible to test your setup with both panels face up and with one with a backing placed about 6" from the panel?
Backing consisting of something like roofing felt or similar low reflective surface?
Just a note about your performance summary at 12:00.
Despite blocking the rear of the face up and face down panels the solar cells still allow light to pass through and some of this is picked up by the rear cells.
From there all your stats are affected by this element.
Assuming the two panels are exactly the same it would be more accurate to calculate the difference between face up @ 402W minus face down @ 254W and equate the difference of 148W (32%) as being the measurement of the benefit of the bifaciality. Unfortunately this is still only an approximation but certainly closer.
This would give a "Theoretical Maximum" of 460W Rated + 148W Bifacial = 508W
I used black plastic on the cardboard blockers, and the blockers are placed against the glass. I think very little light is reflected back
Bifacial panels placed close to a dark color roof, will give you very little gain. However, bifacial panels are not much more expensive and you don't have to worry about back sheet failures.
Good work Dave, Ill look into sungold. Jim
Very informative, much more practical data than what is provided by manufactures,
The specs don't really tell you what you can expect in the real world. I like to test with actual parts in the actual place.
It would be a neat experiment to first run the cold water line, that goes to your water heater, through water pipes attached to a solar array for cooling them down. Would probably be better with non-bifacial panels so you can turn the backs into heat sinks. I wonder if the added cost would be worth it considering a reduction of power required for the water heater plus the increased productivity of the array. If you live in an area with water towers you don’t have to power the water flow, so the only expense is the heatsink mechanism and pipes.
There are systems that are designed to do that. I haven't run the math, but I suspect it would be hard to justify the added cost for the additional equipment.
I have 8 panels 440w topcon ntype biracial, they are great
Biracial?
@@SamPowell-s3g I think that was a typo!
Mirror Mirror on the wall how much power will you give? Sungold sounds like great company to work with.
Most panels have side to side mounting.
Put a gap of 20% of panel width to allow more sunlight to get through to a white metal roof. Say 160mm.
The gap may allow more cooling air flow. 😎
Many rooftop systems are on part of the roof, bunched together.
Shorter mounting rails and fewer clamps and quicker to install.
Sunlight on the metal below may increase heating below panels.
So, temperature readings are needed.
I am thinking of a sloping roof, a 100mm gap between panel and sloping metal roof.
Also, would a forced airflow below the panel help keep the panels cool mid summer heat waves. ?????
I did some testing on a white metal roof, you can see it here: th-cam.com/video/mzqjCsZKUYQ/w-d-xo.html
13:19 - yes, it can work easily: mount the panel on the ground like you did, but only a stand for just 1 panel only
Then use a foil to create a pond around and under the panel, but it needs big pond and not just 2 m around .
If you have a wet acre somewhere else with a pond or so build it there and do the tests with a battery and solar charge controller.
But, and there is a big but: be aware that the usual 3 diodes in those boxes somewhere on the back are NOT rated for this usecase .
We have burned the panel through on the lake just 5 m from the waterline away.
First it did not work that well and we forgot about the test that day. Next evening after the harvest was done that panel was dead and the diodeboxes had melted into whatever. Not sure if there were further damages cause it ended in the scrapyard. We tried that 2 years ago or so. Back then we had only 1 panel left and that was the end of our test period.
WOW! 😯😮
a W shaped reflector 2x the width of panel will work for full back side sun... best for cold winter output
I've done some testing with mirrors, but the results weren't as good as I hoped. I might try it anyway.
Usually you should get slightly over rated power from a panel when new? Rating is guaranteed for a number of years, which means they have to perform above specs when new. I usually measure 104-105% from a new panel.
At what solar irradiance?
@@ProjectsWithDave At what you should get on any clear day with a reasonable solar height. Can be more than 1000W per sqm. You get a solar panel, unpack it point it perpendicular to the sun and load it at the claimed amps on the sticker on the backside. There is no solar business tradition of overrating panels. If it is not delivering the nameplate power out of the box, it is faulty. Preferably should deliver a few percent more than nameplate power to be able to deliver the guaranteed power for the number of years stated in the warranty. UL 1703 certification specifies power rating and degradation.
Good Video Dave! What is the weight difference between equal size bi facial & mono facial panels? You mentioned glass on the back side of the bi facial in the beginning of the video. When doing some simple math on glass weight, I come up with the bi facial possibly weighing 26 more pounds per panel over a mono facial. The reason I bring this up is because of the added weight to an older roof. This may not sound like much but when combined with high winds (such as Santa Ana winds in So Cal) this could be significant. Just think out loud here. Cheers
Yes, bifacial panels are much heaver. Not just a consideration for weight on the roof, but they are also more work to install. Also, you won't see a significant benefit with bifacial panels on a roof.
@@ProjectsWithDaveWhy are bifacial panels also more work to install?
13:24
Make cheep mirrors by gluing mylar survival blankets to plywood, and set up a mirror array behind your solar panel array angled more steeply to reflect sunlight back under to the back face. Might not be *full* sun, but it’d be close.
I would think that anyone living in a snowy environment would benefit the most from bifacial panels in the winter, with the shorter days, and reflective environment.
I that isn't as effective as you would think, I did some testing with it in this video: th-cam.com/video/xD1MT-ek05w/w-d-xo.html
@ I guess that makes sense; it’s easy to forget that there is no such thing as a perfect mirror, and losses accumulate rapidly.
Great panels for a pergola!
They're definitely a good choice for that!
Thanks
COOP
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I really want to know what you guys are doing for ground Mount arrays for these bifacial panels I would really like to see some good comparisons between panels higher up in the air or closer to the ground according to this video i believe you just said that the panels perform better closer to the reflective surface like maybe marble chips white rubber roof tin a mirror or a reflective surface such as aluminum foil or maybe a old solar pool cover.
What's everyone using for really cost-effective ground mounts that works the best for bifacials that are 400 + watts
I appreciate the conscientious data collection and analysis. Did I miss the part where you directly measured front and back working together (rather than blocked back and adding front and back separately). Nobody installs these with blocking on the back.
The front and back together was the the chart that says "With Bifacial Gain": 7:47
@ProjectsWithDave thanks. Appreciate your work.
Great Video again. You never fail to impress. Question: if I had 10 panels facing Southeast and 10 panels facing Southwest (and don’t have micro inverters or optimizers) can I (and should I) connect some SE panels in parallel (or series) with some SW panels? Or should the SE panels be on a completely different string than the SW panels and be connected to a different MPPT?
You should make them separate strings connected to separate MPPT inputs. 20 panels would produce a voltage that was too high for most inventers anyway.
How did you verify the shadow effect on the back side of the panels?
What kind of verification are you looking for?
A sunny winter day with snow on the ground will be a big day for these panels.
Yes, snow makes a noticeable improvement in performance. I measured it in this video: th-cam.com/video/YZWeCUzu0yQ/w-d-xo.html
Wondering if the addition of small DC fans would be worth the trouble. I did a few calculations based on data here and guesses if the fans were very low cost
them probably yes depending on how effective the cooling and longevity of the fans. If I can do it on the cheap I may try an experiment on one of my 3 arrays
You think you have it bad? My panels hit 70+C after a long hot day at 130PM. I guessed as much as I was designing the system so I specified 600w to 440w microinverters with a DC to AC of 1.38 in order to eliminate as much of the loss as possible. Doing so also allows me to hit peak at around 800w/m2.
Sounds like you did some planning to account for your weather conditions. People don't realize there is no one-size-fits-all solution when it comes to solar.
Hey Dave, what part of the state are you in?
You could have a heat pump powered by the panels and cooling the panels as well.
I keep seeing this but don't understand how this can be done.
Hi Dave, I had a solar power system installed on my roof last year and am planning on expanding it with some bifacial panels. I have pretty much filled up the south facing part of my roof so the new array will have to go on the north facing side. It is a standing seam metal roof and is only sloped about 10°. I am wondering if it is worth putting the new panels on a rack mount that will get them up to the optimum angle for my area (San Antonio, TX), which is about 30°. That would mean mounting them at a 40° angle from that part of the roof. I also figure that will help get more light to the backside of bifacial panels. What do you think?
good work dave, recently will prowse got my interest in bifacial. he concluded as you to white reflector . consider white canvas or ? under , . Jim
38* as max angle.. seems shallow for Canada That actually needs 45-50* plus 11* (adjustable) at the border areas.. and I'd only se bifacials on a tracking mount with a white background (roof or stone base (and no weeds)
Can i use my septic system to cool down solar panels of they are positioned in my leech field?
What is the transmittance on the panels?
Just wondering: if you did have a means of actively cooling a panel, as alluded to, why not direct additional sunlight through the front of the panel, rather than perhaps awkwardly directing it through the back side (i.e., towards the sun) in addition to through the front?
Many big solar players have tried it and it does not justify the amount of energy consumed to cool the panel vs extra generated from being cooled.
I wonder what would happen if you had a VERY white reflective panel behind these maybe 2 inches deep to defuse and reflect all the light let in between them to the back of the panel.
I tried the Mylar, but it wasn't as dramatic as I anticipated. Only a few watts improvement: 4:44
water misting or cooling fans for cooling off the panels
Deve I have a question.if you can help me with my power bank
Hi Dave ! From your experience, solar tracker combined with bifacials that have a white / aluminium panel at aprox 50-70 cm distance, can produce the max from a PV system ?
8:06 isnt that 25 deg temp for penal themselves not the ambient temp? doesnt matter anyways, im just asking, great video btw🎉.
Yes, the test without the back side blocked had panel temperatures around 25deg C.
Why don't you do a reflective array behind the panel that redirects full sun to the backside of the panel?
I'm considering a test for that concept.
Try mirror behind the panels
Sum of front and backside power doesn’t seem likely to ever achieve the max of them together. But I’d be happy to be proven wrong! 😅
I think you are right, but I don't know how to prove it definitively. It would take some kind of elaborate mirror system. I don't think I can do it justice. But who knows, I might try it some day just out of curiosity.
4:05 aaaaaand...warranty voided. That was a load bearing sticker
I should have mentioned in the video you can't remove the sticker before inspection. Most inspectors will want to see the specs.
Well done! Thank you
My bifacial 600w can generate 820w of peak power
820-600 = 220
220/600*100 = 36.66% more power 😮
Do you put it on roof or ground?
Hummm a manufacturer lying about the performance to sell more stuff, never heard that from everywhere before.
Can’t you just install 2 regular panels, one facing up, one down?
Use some on the roof of a chicken coop, wonder if they would be beneficial for a roof of a green house.
If you are interested in limiting the sun load in the greenhouse you could alternate glass and solar panels.
Wait a monut, i thought panels output per square meter is 220w if panel has 22% efficieny.
What i am missing guys?
From the datasheet, the electrical parameter of the solar module is tested at STC condition, 1000W/m2 irradiance, 25 degreeC Cell temperature, 1.5 air mass.
Any changes in the environment will affect the energy generation.
Hm, at 10 pannels these sre still 200$ a pop. Only worth it if you're really needing high energy density array. I think theres some 450- 500w panels for half that.
Do I have a project for you good sir. Where do we message you?
You can reach me through the about page on my website: projectswithdave.com/about/
So with 1000 W/m2 irradiance the output is about 360 W. What is the panel efficiency then? I'm asking because you don't mention how much power each m2 of panel generates.
Not sure, but when you show the graph when at minus 10-20 Celsius the efficiency is over 100% of nominal, you are talking about panel temperature, not air temperature. And when you have a very sunny day the panels will heat up to maybe 0 Celsius, or more. Finally, this increased output will affect only the situation when it's much colder and the wind is cooling panels down. Otherwise, it will take place only in the beginning of the cycle of very sunny day. With little sunshine the gain will be to small.
The power per square meter for the front and back independently is in the graph at: 14:23
@@ProjectsWithDave maybe I missed something, but how 1 m2 can produce 400 W? It's close to the total panel output, with the surface close to almost 2 m2.
PS You have a great channel, and a true talent for experimentation. I didn't finish my book on solar (maybe I will one day) - on main key topics, in big part for grid-level projects, economics, ecology and so on - but I wish I were watching your channel when I started, so many things are shown, not just described. Good luck!
@@денисбаженов-щ1б 3:00, the packaging shows SG-460WBG, google the datasheet. The Pmax @ STC is 460W, Dimension - 1994x1198mm, efficiency 19.3%. If you are too lazy to calculate or google it. Take note to account for that 2% reduction in power due to LID for modules using monocrystalline perc technology
I don't think the cost for these is justified based on very little return from the backside of the panel. I guess someone that had very limited roof space might benefit a little from them. These things are expensive.
You can get bifacial panels for less than $0.30/Watt depending on the brand: signaturesolar.com/all-products/solar-panels/?ref=SALE
Bifacials really shine during cloudy or hazy days.
@@ProjectsWithDave But you are using the Sun Gold Power 460W bifacial solar panels for your review.
I'd write about the 'How to make your own solar reflective paint' that reflects at the frequencies used by panels, but I know the comments never get read and you content creators only say "comment" to please The Algorithm.
So no: DON'T look into it.
And you just got another algorithm pleasing comment. Bully for you!
there is no dramatic increase in performanse rhe full video is nonsens.
yes the make ~5% more if the panels are lift 2 meters over the groud in the air, aree this 5% importand onm any way if to get this is confusing stuff to do important???
no
🤨You need a lot more knowledge of physics, where the technology itself comes from.
And with cheap thinking, cheap tests, your results are nothing, which you actually prove.
The bad thing is that you expose people to things that you are not sure about, due to lack of knowledge.
Joker: It's not about cables and electricity, which you understand more or less.
But, you're on the right track. Keep going.
Think about where you are wrong.