Tesla's "solar roof" Event - Hosted at Universal Studios

[Nigel Tufnel]

I'm going to order the powerwall and plan to have the solar roof installed instead of a standard roof top array. I wonder about the "indirect-sun side" of my roof issue. I wouldn't have the raised panels installed over that side of my roof, so would the Tesla roof be expected to produce more electricity since it'll pick up some energy from the "other side" of the roof? Or maybe the Tesla roofing panels can be installed with or without integrated solar cells?

 

[Garlan Garner]

Not in response to Jeffk and his funny joke. But to the AC-DC convo in general

I would like to know how AC is more dangerous than D.C. OHMS law doesn't care if it's AC or DC.

AC solar is much safer than DC.

AC is 120v to ground, 120/1000ohms is .12 amps. Ouch, with the exception of extreme conditions most people will be ok. See table below.

DC residential can be 600v to ground (Commercial 1000v to ground), 600/1000ohms is .6 amps. This is in the respiratory arrest, death range.

SolarEdge normalizes at 350vdc. This is above the let go range.

Solar Edge system shut down to 1V per panel with any disconnection or interruption.

For the internet savy....look up how many people have died putting up DC solar solutions. Come on... Does anyone have any good news?

 

[e-FTW]

Based on my current understanding, here are the pros and cons right now:

Pros:
1) The solar shingles look fantastic. Far better than anything I've ever seen before. They knocked this one out of the park.
2) Powerwall 2. Stats look great. Better load, bigger battery, integrated inverter, looks good. Pricing-wise, looks like a better deal than Powerwall 1.
3) The Tesla merger. Maybe just my opinion, but I feel a lot better with the idea of solar from Tesla/SolarCity than just solar from SolarCity. Among other things, it might greatly accelerate how quickly the tech becomes available in places it previously wasn't.

Cons:
1) Looks like it's got a ways to go yet before it's market ready, in terms of both product maturity and regulations.
2) Solar panel density. The fantastic aesthetics of the panels noticeably impacts panel density. And based on what I've read, they will still need the same set backs as traditional rooftop solar, so they lose a potential advantage there I thought they would have. I was hoping you might be able to get more solar on your roof with these as compared to traditional rooftop solar, but now I think it will actually be less.
3) Only good for houses needing new roofs.
4) General lack of information. There are still many unknowns.

Agreed on con #4. My question is this: no indication on how this is all connected, is there room required above the original roof for cabling and inverters?

 

[Garlan Garner]

Great to see that video. I have 24 SolarWorld panels and live where we have lots of snow. Buildings here need to be engineered for 240 pounds/sq.ft. roof load. Panels have survived one winter (several feet of snow on panels) with no problems. We'll see what this winter brings.

Amen, I go with history.

FOLKS...watch the live progress of the last 4 years of solar panels on my Chicago roof. I haven't swapped anything out or been up there once in the last 4 years.

 

[Owner]

My dream home used to be a straw bale home. However, the city doesn't allow them here.

I was briefly looking at straw bale also. The problem was that there was simply not enough data around it to get something that "innovative" built. The architect just didn't know what to do with it and said I would have to provide tons of data (mean spend tons of money) to prove to the planners that it would be earthquake safe and all of that.

If I were Elon rich, I'd definitely have done something more interesting. I built as unconventionally as I could but stuck to stuff that was already tested enough to be financially feasible.

 

[dhanson865]

The pics are real, the houses are not.

You can physically walk into those houses. They aren't holograms.

I guess you and I use the word "real" differently.

Sure they might not have working plumbing in the bathrooms and might have zero insulation but they are just as real as the homes in a new subdivision that a builder starts selling as 80% complete or whatever.

 

[Garlan Garner]

Agreed on con #4. My question is this: no indication on how this is all connected, is there room required above the original roof for cabling and inverters?

True - we

I was briefly looking at straw bale also. The problem was that there was simply not enough data around it to get something that "innovative" built. The architect just didn't know what to do with it and said I would have to provide tons of data (mean spend tons of money) to prove to the planners that it would be earthquake safe and all of that.

If I were Elon rich, I'd definitely have done something more interesting. I built as unconventionally as I could but stuck to stuff that was already tested enough to be financially feasible.

If I was Elon rich I would have a crayon box of Teslas.
One of every primary color.

 

[deonb]

So....people that live where there is terminal velocity...please don't get solar panels or Tesla's solar initiative. Is that good for everyone?

Or you could just tell that strawman of yours to stop lifting weights on the roof.

 

[Garlan Garner]

I currently have SolarWorld panels, and they claim to be pretty resident to hail:

Some of that is probably because the large surface can help distribute the energy of the impact. Single tiles might be more effected.

Even in the VTesal Weight drop video, the solar tile cracked, probably damaging the PV cel.

Fantastic video.

I wonder what the scientific explanation is on those super duper panels. My panels are obviously made the same way. I walk on mine while on the roof. Super Duper velocity hail hasn't done anything to them. Nothing.

 

[Garlan Garner]

Or you could just tell that strawman of yours to stop lifting weights on the roof.

My panels seem to respond the same way that the panels in the video responded when 1 inch ice balls were shot directly at them above terminal velocity out of a cannon.

That's all I know. I don't have formulas or calculations......I just have all of the confidence in the world that they will CONTINUE to respond favorably in all weather conditions.

I would need to be able to buy and install one of the Tesla Cells to make the same statement about them.

 

[deonb]

That's all I know. I don't have formulas or calculations......

Evidently.

I just have all of the confidence in the world that they will CONTINUE to respond favorably in all weather conditions.

I would need to be able to buy and install one of the Tesla Cells to make the same statement about them.

That's all that Todd called for initially - to see how it holds up in a real world test against "hail at terminal velocity" ... aka: "hail under normal circumstances"... aka: "hail".

It's hard for people to instinctively know whether a heavy weight travelling slow would do the same damage as a small weight travelling fast. Tesla is not helping by not providing any context or details for their experiment.

 

[roblab]

.... is there room required above the original roof for cabling and inverters?

Since the glass shingle is fairly thick, I would guess that one could design the plugs and wires that would do the power out which would fit just along the top edge of each row of shingles. In case people don't know how shingles work, they overlap, and there's space under them as they fit above the lower rows. My main concern was more with how my 230 lb. resting on one foot right at the juncture would stress the shingle, and how the nails/screws would hold them without breaking the glass. I would guess that the inverters could be many feet away. My roof system (panels) runs 60 volts down to my patio closets where the inverters live. Several wire runs. But we don't know the power, or how they might be connected in series or parallel, so no facts, just conjecture. There is room for wire, though.

 

[3Victoria]

Jeesh, it was a short clip in a demo. patience is a virtue.

 

[Garlan Garner]

Evidently.

The point is....formulas don't explain everything. [obviously] That's what is evident here.

Live / Historical and videos are also evident.

 

[Garlan Garner]

Ohhh no Jeff. That's not good at all. I can't even watch that.

Can that please be taken down?

 

[Owner]

Ohhh no Jeff. That's not good at all. I can't even watch that.

Can that please be taken down?

I just reported it. Elephants are my favorite animal (not in a political sense), they are super smart.

 

[JeffK]

Ohhh no Jeff. That's not good at all. I can't even watch that.

Can that please be taken down?

Me either, I deleted it... But that's Thomas Edison for you! For someone, especially someone who works with electricity and solar panels to say they've never heard of AC being more dangerous than DC, that's just crazy. Poor Elephant. Edison was not a nice person.

 

[AudubonB]

...live where we have lots of snow. Buildings here need to be engineered for 240 pounds/sq.ft. roof load. Panels have survived one winter (several feet of snow on panels) with no problems. We'll see what this winter brings.

If that number you give - 240 lbs/sqft - is correct, it had better be referring both to live load and dead load (dead load here will refer to the weight of the roof and its structural members themselves - these don't change). There is NO WAY any code would call for 240 lbs live load; in fact, it probably would be close to impossible to build to that. I went way overboard in designing my big roof in Alaska - 12" centers with 18" engineered trusses - and that's good for about 150 lbs. live.

Put another way, to pile 240 lbs on a square foot of roof you would need to have - at a factor of 10" snow equaling 1" rain - 461 inches of snow on the roof, or 38 feet.

 

[mspohr]

If that number you give - 240 lbs/sqft - is correct, it had better be referring both to live load and dead load (dead load here will refer to the weight of the roof and its structural members themselves - these don't change). There is NO WAY any code would call for 240 lbs live load; in fact, it probably would be close to impossible to build to that. I went way overboard in designing my big roof in Alaska - 12" centers with 18" engineered trusses - and that's good for about 150 lbs. live.

Put another way, to pile 240 lbs on a square foot of roof you would need to have - at a factor of 10" snow equaling 1" rain - 461 inches of snow on the roof, or 38 feet.

Yes, it is a lot...
I just double checked the structural calculations on the detached garage we just built and the snow load is 245 psf (plus 15 psf dead load) at 6440 ft. elevation (Placer County, CA). Construction included steel I-beams.
We do end up some winters having 6 to 10 feet of snow on the ground. This is compressed from many storms so probably pretty dense. The roof can get 4 to 6 feet.

 

[AudubonB]

Nice code writing there: "15 lbs dead + 245 live" - I guess Placer Cty officials got a smoking great deal on I-beams made out of a fine Indestructium+Unobtanium alloy that they then sell to contractors, cuz there ain't no 15 lbs. of real material that can hold up itself plus 245 of live. No how no way.

I'll put it another way then put it to bed. In order to get 245lbs. of water on a square foot of your roof means you have 47 inches of rain equivalent on that square foot. Typically we figure 1 inch rain is equivalent to 13" snow; that can vary from 4" for super-packed snow (think on a road surface after many vehicles have driven on it); super-fluffy uncompacted Wasatch snow can be as much as 50 inches per inch of water.

Fun stuff - for years I was an Apaid NWS Weather Reporter at the Paxson Station. Had to read and report the data nine times every day, starting at 0545. They finally automated the station three years ago, meaning I lost the job but stopped losing my hair!