EEVblog #1233 - The Demise Of Solar Roadways

[Fungus]

SR4 panels are in!

Maybe we can change the thread title to "rebirth of solar roadways"?

[coppice]

Maybe we can change the thread title to "rebirth of solar roadways"?

An then back again next week when the new roadway dies?

[Domagoj T]

It's a stillborn anyway.
 

[floobydust]

At least they're working on improving them, but not sure who is paying for that? We all know the system is plugged-in using grid power 
Strange the epoxy reacted with the blue, white, yellow LED's.

[james_s]

Are the yellow LEDs the sort that uses a phosphor? The blue and white LEDs are both blue emitters, so perhaps the intense blue light is affecting the epoxy the same way UV from sunlight breaks down polymers?

[Domagoj T]

They are up and running. The pattern they are displaying is S, R, 4. Ingenious.

It appears that it's overcast in Sandpoint, but these new and improved LEDs still aren't particularly bright, even from above. Maybe SR5 will be revolutionary.

[Brumby]

I have to give it to them...  They keep on pushing - and you kinda hope they will be successful.  Shame our current understanding of physics and economics isn't aligned with their aspirations.

If nothing else, they will have put in a lot of effort that will show how well the idea doesn't work - effectively, that is.

[EEVblog]

The Solar Busway Graveyard! 

[floobydust]

What was the cause of death?

[EEVblog]

What was the cause of death?

Busses rolling over solar panels 

[floobydust]

What was the cause of death?

Busses rolling over solar panels 

In the graveyard, nothing looks busted up or destroyed. It's a very thick concrete substrate, so no flex issues like the other failed roadways. Unless those failed panels are in landfill, not the graveyard. The only other difference is the coating is gravel granules of something that obviously could not compete with a bus tire. Who'd have thought?

Are the yellow LEDs the sort that uses a phosphor? The blue and white LEDs are both blue emitters, so perhaps the intense blue light is affecting the epoxy the same way UV from sunlight breaks down polymers?

SR3 looks like they're using Cree XLamp leds, it looked like amber not "yellow" ?  The encapsulation caused trouble.
Cree XLamp Chemical compatibility
"Any VOCs present in an SSL system can diffuse into the gas-permeable silicone lens and encapsulants of the LED. Within the molecular structure of these silicone materials, the VOCs will occupy a free space in the interwoven silicone polymer. With subsequent exposure to high photon energy emitted from the LED, along with the heat from the lighting system and the environment, the volatile compounds trapped in the LED's lens or encapsulants can discolor. This discoloration of the trapped VOCs can degrade the light emitted from the LED. This discoloration tends to occur in blue, royal blue and white-light producing LEDs that use blue wavelength LED chips with yellow phosphors for spectrum conversion. This sensitivity to VOCs is not unique to one LED manufacturer but is a known problem for all types of blue, royal blue and white-light LEDs."

[nctnico]

What was the cause of death?

The segments don't seem to be damaged; it is just that the surface finish didn't stay on the panels. They probably repurpose the Solaroad segments after putting a new surface finish on them but this time likely in lane with lighter traffic first. AFAIK this was the first field test with heavy traffic so chances of problems occuring where high to begin with.

[EEVblog]

Ho, Ho, Ho, Merry xmas!

[floobydust]

Uh, they supposedly have a heater in the modules but all I see is a little hole in the snow 
Why don't we take it to the next level.
Invent superconducting solar roadways. They must be kept very cold.

[Domagoj T]

TF says that the lighter area around the panels looks like a dry patch from being heated.
I would offer a different hypothesis - it's salt they spread around in anticipation of the snow, hoping that would melt it.
In any case, it's not working.

[Domagoj T]

And we have a first failure. A bright pixel: