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

[ohmman]

I'm assuming this is true for Southern California also. And with the global warming we have seen already the last few winters are noticeable warmer here making any hail even rarer.

I would think the warmer winters would make for more precipitation in the form of thunderstorms instead of generic atmospheric rivers (like this great one we're in right now). There are some thunderstorms today, for instance. Those will increase the chance of hail. Not sure either way, but that's just my overall logic on how warmer winters will affect it. Of course, if we keep getting ridging in the Pacific, we'll have no precipitation at all, and maybe that's more what you're describing.

You're definitely right about the Sierras, though. Here's Tahoe in August 2014:

:

 

[InTheShadows]

What needs to be solved?

No, AC is more dangerous than DC... Now when combined, ACDC has big balls and is on a highway to hell.

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.

 

[Skotty]

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.

 

[mspohr]

Ordering now open at Tesla Powerwall. Takes a credit card. I gave Tesla $1,000 for a deposit for 2. Shows up on my credit card as "TESLA MOTORS DEPOSIT".

From the order page, which allows quantities of 1-9 (with $500 deposit required for each):

The above installation and supporting hardware estimate is fixed regardless of number of powerwalls ordered, and the rest are times the number of PowerWalls reserved.

Tip: copy the URL (screenshot if your URL shows) for the "Thank you for your order" text. It has an "EN"# that might be important. But, it immediately showed up in MyTesla, so no problem there.

Now, in Tesla.Com MyTesla:View attachment 200499

Here's the email I got:


Attached to that email is a "Powerwall Order Agreement" that I skimmed thrice and still don't understand. I'll start parsing it at some point later when it begins to matter more to me.

---

More info at Our solar roof has integrated solar you can’t see | SolarCity

and @TeslaMotors is tweeting pics of the roofs.

Can you DIY?
Can't be that hard to nail it to the wall and wire it. My electrician should be able to do it for less.

 

[mspohr]

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.

The problem with AC is that the frequency interferes with cardiac conduction leading to fibrillation and death.

 

[Garlan Garner]

Sure, but we don't know what kettle bells those were. Could be 5 lbs - could be 100 lbs.

A 5 lbs kettle bell falling 1 meter will have an impact force of 220 N
A 1" hail stone weighing 2 oz at terminal velocity (68mph) will have an impact force of 277 N

Once the kettle bell gets to 10 lbs, it will generally hurt more. HOWEVER - the largest hailstone ever recorded (8 inches / 1.94 lbs) would have exceeded 110mph and had an impact force of 12788 N - which would be equivalent to dropping a 286 lbs kettle bell 1 meter.

ok Deonb. This is hilarious to me.

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?


I've had them for 4 years in Chicago through snow wind and hail.....check out the "live" progress of my panels on the link below. I know there is some way on the internet to look up when my panels were hit with terminal velocity hail in the last 4 years.....however they are just fine.

 

[JeffK]

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.

You can also google Edison's Animal electrocution trying to prove Tesla's AC was dangerous. There's a great deal of information describing why AC is more dangerous than DC.

Also one thing to keep in mind regarding solar is that there's no such thing as AC solar... Solar panels are DC. Whether or not they have a built in inverter is another story.

Batteries are DC not AC.

Solar installations are low voltage... the high voltage happens between a dc-dc converter and an inverter.

 

[AudubonB]

"My Indestructo-Roofing material held up just fine. Too bad my house collapsed."

 

[Krugerrand]

To be honest with you....I thought the test was a failure for the solar roof. Why in the world would you put up a video of your product cracking.

 

[liuping]

Well I've seen hail destroy car sheet metal, blow out tempered glass...I'm not sure I'm going to believe that until I see them fire up the testing guns.

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.

 

[Owner]

4) General lack of information. There are still many unknowns.

I'm very much struggling with this one. It sounds like to me that they made some really nice looking shingles. But they haven't figured out the wiring yet.

So how can Tesla claim this will be cheaper to install than a traditional roof??? If they have not finished the wiring yet and have ZERO real world installs, that is a huge claim. Dow had a product in this space but discontinued it after 5 years.

I'm not doubting that there is some technology behind it but I'm not believing the hype until there is real data. Powerwall was oversold to be useful, but it only makes sense in limited markets. I am not a fan of hype, or cool technical products that don't deliver real measurable benefits in real world situations.

 

[electracity]

[QUOT

You can also google Edison's Animal electrocution trying to prove Tesla's AC was dangerous. There's a great deal of information describing why AC is more dangerous than DC.

Also one thing to keep in mind regarding solar is that there's no such thing as AC solar... Solar panels are DC. Whether or not they have a built in inverter is another story.

Batteries are DC not AC.

Solar installations are low voltage... the high voltage happens between a dc-dc converter and an inverter.

Typically in series with 350v DC coming off the roof. This is what concerns firefighters.

 

[dgpcolorado]

Did you incorporate any PassivHaus tenets (air-tightness, high insulation, air heat exchanger) ?

No, that stuff is mostly newer than when I built my house eighteen years ago. I did wish I could get a heat recovery air exchange system but they weren't commercially available at the time, so far as I was aware, and I was on a tight budget, with wildfire safety the highest priority (the exterior walls are made from concrete and steel). I don't even know if heat recovery air exchange systems are easily available now. Since I have radon in the house — lots of uranium in the sedimentary rocks here — it would be nice to circulate outside air during the seven months of heating season (the rest of the year I can have the windows open much of the day). Although I'm not sure if it would be practical to retrofit an air exchange system into the house.

 

[S'toon]

Yes, as much as possible the home is passive. I don't have to use A/C unless it is really hot for multiple days. I have clearstory windows that can cool the house down at night.

The winter I do need heat as the sun is not out every day and there is not that much sunlight hitting the house to truly heat the whole thing. I have an acre of land but not a huge spread where I could take advantage of the sun to heat the whole thing, and there is a 100+ year heritage oak also on the southern side. So I couldn't go truly passive as the lot would not allow it.

But it is radiant floor heating running off of natural gas.

100% passive is quite hard for most people. There is someone in town who built their house without heat and I think they are nuts. They did put in one large fireplace in the middle of the whole house. All I could think was "that's a ton of pollution open wood fire" but somehow it is LEED certified. I would not be comfortable in a house that is 55 degrees all day long. I can't imagine them being able to resell the thing and having to retrofit a real heating system.

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

Last year I went to a talk given by a talk by a young couple who built a new passive home. Never heard of them before then. Now a solar powered passive home, possibly with geo-thermal heating/cooling.

 

[JeffK]

[QUOT


Typically in series with 350v DC coming off the roof. This is what concerns firefighters.

Yeah, I'm too old. I was thinking of the old fashioned installations

 

[jimmyjohn]

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

Last year I went to a talk given by a talk by a young couple who built a new passive home. Never heard of them before then. Now a solar powered passive home, possibly with geo-thermal heating/cooling.

Any interest in rammed earth?

 

[InTheShadows]

You can also google Edison's Animal electrocution trying to prove Tesla's AC was dangerous. There's a great deal of information describing why AC is more dangerous than DC.

Also one thing to keep in mind regarding solar is that there's no such thing as AC solar... Solar panels are DC. Whether or not they have a built in inverter is another story.

Batteries are DC not AC.

Solar installations are low voltage... the high voltage happens between a dc-dc converter and an inverter.

I'm a NABCEP certified solar installer and OSHA 30 certified. All DC solar installations with the exception of DC off grid are high voltage (meaning over 50v to ground). The panels are strung in series to 400-1000 volts.

There are AC solar panels. We install them. Sunpower makes them. They have a microinverter built right into the solar panel. The requirements for installing an AC based solar system dramatically less than a DC based system. This is why code now requires rapid shutdown and the DC conductors to be in metallic conduit. Those requirements do not exist for AC systems and the reasons are safety.

I know nothing about the experiments you are talking about. That may be true for the same voltage and resistance. However we are talking about voltages that are 3x+ what you deal with in an AC system.

I will willing grab a live 120v AC circuit with no PPE. There is no way I would do the same with a 400vdc residential solar string, let alone 800-1000v.

I do know for certain that .6 amps DC is much more likely to stop the heart than .1 amp AC.

 

[mspohr]

I'm a NABCEP certified solar installer and OSHA 30 certified. All DC solar installations with the exception of DC off grid are high voltage (meaning over 50v to ground). The panels are strung in series to 400-1000 volts.

There are AC solar panels. We install them. Sunpower makes them. They have a microinverter built right into the solar panel. The requirements for installing an AC based solar system dramatically less than a DC based system. This is why code now requires rapid shutdown and the DC conductors to be in metallic conduit. Those requirements do not exist for AC systems and the reasons are safety.

I know nothing about the experiments you are talking about. That may be true for the same voltage and resistance. However we are talking about voltages that are 3x+ what you deal with in an AC system.

I will willing grab a live 120v AC circuit with no PPE. There is no way I would do the same with a 400vdc residential solar string, let alone 800-1000v.

I do know for certain that .6 amps DC is much more likely to stop the heart than .1 amp AC.

Sorry for the off track question but do you have any experience with the AP Systems microinverters?
APsystems Microinverters – APsystems USA | Leading the Industry in Solar Microinverter Technology

 

[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.

Then make sure your insurance covers your panels / cells before you put them up.

 

[mspohr]

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.

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.