Testing Gains From Bifacial Panels | Round 1

I am trying to select the best panels to mount with a ballast system on my flat roof. Since the membrane is white I would expect I should be able to harvest a bit more power from bifacial panels even when only mounted at a 10-degree angle. I will run a test to see what the actual gains are on a normal day with a mix of sun and clouds.

DISCLAIMER: This video is for entertainment purposes only. Also, this video and description contain affiliate links, which means that if you click on one of the product links, I’ll receive a small commission.

[everydaysolar]

DISCLAIMER: This video is for entertainment purposes only. Also, this video and description contain affiliate links, which means that if you click on one of the product links, I’ll receive a small commission.

[DialedN_]

The bifacials would benefit GREATLY from gaps between the panels to allow direct sunlight to pass between the panels and reflect back off of the roof. In this test there were no gaps.
Also because the front of the panels were resting on the roof you killed 100% of the light that would normally jump up from in front and refract directly onto the back. The front and the back of these panels should be lifted for max benefit.
I believe a solar pergola would be an ideal use case for bifacial solar panels. With the panels so high off the ground, they would benefit from reflected light from 360 degrees around.

[realeyesrealizereallies]

I have the Bifacial panels, two separate DIY ground mounts, that can follow the sun and tilt, with a mobile reflective system underneath, I have great results..35% gains in colder weather..Your panels are too close to the roof..Bifacial is better for ground mounts..

[gregc]

I think blue tape lets light through. Put a piece on a bright window and you should see light passing through it.

[phakeAccount]

There's been a lot of talk lately about vertical bifacial panels collecting more than your standard angled panels.

[Waldoe]

Bifacials shine in ground mounts or when elevated enough in a white rooftop. If you had lifted the bottom part, you might have seen 6-10% gains in that kind of day. The black frame does not help much either.

[Nifty-Stuff]

I like that you're doing these comparisons, but ya... more space between them and the ground/roof would be good. Also, please do these tests (or at least updates) on a sunny day.

[Bowhuntersgoxzx]

There are articles that state not to put Bifacial solar panels onto roofs of houses, the backs of panels will be too heavily shaded on the roof which kills most of the production from the back, as DialedN_07 said create some gaps between the Bifacials will help some but I would also suggest placing Mirrors or Chromed metal sheeting (online or from Lowes or Home Depot type stores) and place under the Bifacial panels gaps to reflect the sunlight to the back of the panels and they will pop. Ground Mounted with Bifacial panels is the way to go and put a layer of white gravel rock under them to reflect indirect sunlight to the back sides of the Bifacial panels or have gaps for sunlight between panels and lay down mirrors or chromed metal sheeting as I mentioned for the roof. Thin Chrome Metal Sheeting can be fairly inexpensive.

[mattsimon]

other users are testing them mounted vertical in a north/south mounting position to get better morning and evening results.

[PjotrII]

Youtube expert here! The Bifacial panels need light to bounce to gain a (usually 7-12%) maximum ~20((30))% increase. For that they might need to be "higher up" (from the roof so light bounces on the backside), there might need to be distance between panels (10-30 cm), so that light get "in under", 3) you can reflect light in behind by reflecting material (foil paper or some white painted plank).

[bsylvia]

I set up my panels on top of emergency Mylar blankets & it works great. Layout the blankets, secure them down with wooden strips on all of the ends, then set up the EcoFlow 220W Bifacial panels on top.

[mattsimon]

Really like these comparison vids - recently watched another similar vid where the creator also mentioned how much better solar production was when the ground is snow covered

[bobmonztr]

My PV2 is 2790 watts, 465x6 bi facial, feb19 pv2 was at 3162 watts . In thick clouds 465 becomes 105 watts. Thess #s are south facing 90 deg straight vertical ground mount with snow. 62 bonus watts per panel. With 27 panels that is 1674 watts as a bonus.
Jinko Solar JKM465M-7RL3-TV 465W, Bifacial

[ChrisSelling]

Great test setup and data. I might try the same test with one change, a 6-12 in. light gap between the panels. My understanding is the would allow more reflected light to reach the back side of the panels. The same gap at the head and toe of the panel may also aid in producing more reflected energy.

[AySz]

I'd be curious about a comparison where the panels are mounted vertically (e.g. 90 degrees, like walls or fencing) for applications where the area needs to be more passable. The first time I saw these, the researchers were giving examples of applications where tall farm equipment was running between aisles of crops.

[Teslavangelist]

I think bifacials shine most with vertical arrays. No shading if the ground, so allows max reflection of light, esp in snow or white ground material

[johntierney]

For a test, I would have gone with 2 vertical mounts. Put a tape and untapped panel on each vertical mount. And alternate the the front/back panel on each vertical.

[donaldhoudek]

The panels need to have more space and a reflective area under them. Something like using them as an awning for a patio with light colored things under it. The way you have them situated for this video, there is not enough area/light on the underside. After I install my white PVC privacy fence on my north property line, I will be mounting 15 bifacial panels in front of it. The area along the fence has a 4' border of white sea shells on the ground. The north property line has no issues with shade all day so that will be a great location for solar power production.

[russell]

Good job but at 10% you don't have any slope to expose back to light. This is probably not good for southern areas. In far north where mounting is at 45 degrees or more far more light would be availabe to back of panels. The sweet spot for these might be in north, vertical to get rid of lessened power when snow covered, as high on property as possible to be exposed to the sky as much as possible. Yes 30 feet up on a roof you get more sky exposure than in ground, especially if there are trees. Indeed, the brightest area of sky, greastest sky glow during the day is in the NORTH

[brucemurray]

Interesting. I think the wooden mount support blocked lots of light from getting to the back of the panels. Build some kind of standoff that would get them off the deck at least 6 inches especiall in the front. Good Luck.