Powerwall 2 and Integrated Solar • Hacker News Board

Re: Powerwall 2 and Integrated Solar

#151

Post by usrusr » Sat, Oct 29, 2016, 10:06 AM UTC

intrasight wrote: post #92

JoeAltmaier wrote: post #66

Earlier quoted context omitted.

Hm for that price I can install a natural-gas generator. Have power for days if necessary, full power on all circuits.

3 of my 4 adjacent neighbors have natural-gas generators. That gives you an indication of the power reliability here. Note that I don't blame the utility, and I'm not in some backwater ($1M+ homes around me). It's just that we really like our trees here, and sometimes a branch will break in a storm and take out the neighborhood. My gripe with the generators is they are noisy. A Powerwall would be silent and would han…

Falling branches don't cut buried power lines. This has everything to do with crappy infrastructure and nothing with love for trees.

Re: Powerwall 2 and Integrated Solar

#152

Post by beambot » Sat, Oct 29, 2016, 10:08 AM UTC

botty_throwaway wrote: post #135

beambot wrote: post #122

Earlier quoted context omitted.

Are you sure about those shipping costs to a residential address...? Professional installation? Process and guarantees from a reputable American OEM? Breakdowns and warranties? I think you're missing a lot of costs beyond the raw materials...

Regarding professional installation, those costs are not factored into the base price. It's an additional cost to both parent's DIY method and the Powerwall. As for reputable warranties against breakdowns, please check out the fine print of the Powerwall warranty terms and conditions. It's a '10 year warranty' with some very special legalese baked inside that may make you reconsider the cost premium commanded by guar…

I wasn't disagreeing with you... it is a luxury: peace of mind, being a patron of quality engineering, and having someone to call when shit breaks. Plus, good marketing helps. Seems like a good business strategy to me...

Re: Powerwall 2 and Integrated Solar

#153

Post by beambot » Sat, Oct 29, 2016, 10:11 AM UTC

rsync wrote: post #97

Animats wrote: post #78

The thing is cloud-connected, remote-controlled by Tesla. That presents a problem. Will the cloud service behind it last the life of the system? Most cloud services evaporate within five years.

"The thing is cloud-connected, remote-controlled by Tesla. " If your use-case is backup power in case of utility failure, how does that work ? If utilities fail, the network connection to the battery may also fail, right ?

It's not hard to imagine the solution: fall back to sane defaults like every other system not connected to the cloud.

Re: Powerwall 2 and Integrated Solar

#154

Post by jrv » Sat, Oct 29, 2016, 10:19 AM UTC

antmldr wrote: post #150

manav wrote: post #75

I haven't looked into it yet, but I'm curious about using utilizing my Teslas in case of emergency for power. With 75kwh+ each (leased so no concern about cycles) I don't think I'd need a powerwall at home.

Musk and JB got asked about this (I think at the 2016 AGM?). Their response was basically "yeah we get asked this a lot; No, because of the make up of the cells makes them inappropriate for the number of cycles."

That, plus they said that you'll often want to use the car at the same time as someone else uses electricity in the house.

Re: Powerwall 2 and Integrated Solar

#155

Post by TheSpiceIsLife » Sat, Oct 29, 2016, 10:21 AM UTC

extrapickles wrote: post #144

TheSpiceIsLife wrote: post #62

Earlier quoted context omitted.

From when I was reading more about solar cells I recall there being something about the distance from the conductor (the two stripes visible equidistant from the midline of the cell) being a problem especially with monocrystalline cells, which these appear to be. I think this was more a problem for cells that had the conductor fixed to the back of the cell. Google image search for monocrystalline solar cell and you'l…

I'm not sure you can even make a mono crystalline ingot eliptical. The process heavily relies on spinning the ingot while pulling it out of a silicon puddle which results in the round shape.

I've had a few moments recently where I've thought "how can it be I haven't thought to look this up on YouTube before now", and here we are.

I found this[1] video that explains how to grow a monocrystalline silicon ingot that weighs 440 pounds, and you're right it is spun as it's extracted from molten silicon.

1. https://www.youtube.com/watch?v=aWVywhzuHnQ

Re: Powerwall 2 and Integrated Solar

#156

Post by jacquesm » Sat, Oct 29, 2016, 10:26 AM UTC

Loic wrote: post #118

Quick question for the people living in the US (Target customers of the Powerwall). What is your yearly power usage? On the website[0] they put for sizing 10kWh/day/BR. Which means 14600kWh/year for a 4 bedroom house. Here in Germany, working from home with a 4BR+office house, we are using 2550kWh/year. So, I suppose the Tesla sizing is to support a "peak day" usage, but still, I am surprised by the calculations. Thi…

The big difference is because of air conditioning and baseboard heating, two things that are relatively rare in Europe.

Re: Powerwall 2 and Integrated Solar

#157

Post by elorant » Sat, Oct 29, 2016, 10:28 AM UTC

Loic wrote: post #118

Quick question for the people living in the US (Target customers of the Powerwall). What is your yearly power usage? On the website[0] they put for sizing 10kWh/day/BR. Which means 14600kWh/year for a 4 bedroom house. Here in Germany, working from home with a 4BR+office house, we are using 2550kWh/year. So, I suppose the Tesla sizing is to support a "peak day" usage, but still, I am surprised by the calculations. Thi…

Athens, Greece here. 2BR house with 2 AC units and electrical heating. Around 5.500KWh/year.

Re: Powerwall 2 and Integrated Solar

#158

Post by olex » Sat, Oct 29, 2016, 10:32 AM UTC

Loic wrote: post #118

Quick question for the people living in the US (Target customers of the Powerwall). What is your yearly power usage? On the website[0] they put for sizing 10kWh/day/BR. Which means 14600kWh/year for a 4 bedroom house. Here in Germany, working from home with a 4BR+office house, we are using 2550kWh/year. So, I suppose the Tesla sizing is to support a "peak day" usage, but still, I am surprised by the calculations. Thi…

That's a very interesting number. Here a comparison, from Germany too: I used to live with 3 flatmates for several years in a 4BR apartment (165m²), our yearly usage averaged 5500-7000 kWh. That included heating water (electric boiler), but no room heating or air conditioning.

I've recently moved out into a 1BR, 63m² apartment, and am targeting 1500-2000kWh - don't have any usage numbers yet since it hasn't been long enough, but those seem realistic to me.

Re: Powerwall 2 and Integrated Solar

#159

Post by TheSpiceIsLife » Sat, Oct 29, 2016, 10:39 AM UTC

usrusr wrote: post #151

intrasight wrote: post #92

Earlier quoted context omitted.

3 of my 4 adjacent neighbors have natural-gas generators. That gives you an indication of the power reliability here. Note that I don't blame the utility, and I'm not in some backwater ($1M+ homes around me). It's just that we really like our trees here, and sometimes a branch will break in a storm and take out the neighborhood. My gripe with the generators is they are noisy. A Powerwall would be silent and would han…

Falling branches don't cut buried power lines. This has everything to do with crappy infrastructure and nothing with love for trees.

Good luck finding someone willing to pay to have squillions of kilometres of above ground power lines buried.

Sydney alone has 63,000 kilometres[1] of overhead power lines. One estimate puts the cost at $23.37 billion.[2]

1. http://www.smh.com.au/articles/2002/07/29/1027926858231.html

2. https://www.ipart.nsw.gov.au/files/7b5531d9-cf65-4b1b-ae7b-9...

Re: Powerwall 2 and Integrated Solar

#160

Post by chadcmulligan » Sat, Oct 29, 2016, 10:46 AM UTC

Roritharr wrote: post #148

martin_bech wrote: post #127

Earlier quoted context omitted.

They would have more than enough power, but you cant pull power out of a Tesla. That would make supercharging to good of a deal.

Never thought of a Tesla as a driving bucket of electricity.

It's a thing https://en.wikipedia.org/wiki/Vehicle-to-grid basically use all the car batteries as grid storage while they're sitting around