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Powerwall 2 and Integrated Solar

powerwall.tesla.com

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Re: Powerwall 2 and Integrated Solar

#191

Post by Klez1993 »

usrusr wrote: post #178
Klez1993 wrote: post #166

Earlier quoted context omitted.

"They're also charged to full capacity or depleted to empty a lot of the time." Does it affect battery life if I keep my phone charged even if it's at 100% ? (My phone is charging during the night, so it will be at 100% for a long time and keep charging). If it reaches 0%, how does that impact battery life compared to reaching 20% and charging up ? I never looked up these things but it might influence how I charge al…

Modern batteries deteriorate from heat and from the time they spend at the extremes of their charge cycle. As a general rule of thumb, you would get the lowest amount of wear by keeping the battery as close to 50% as possible all the time, only charging higher than that right before use and just enough to make it comfortably to the next charging opportunity. One of the worst things to do to a battery (not as bad as a…

Thanks! Will definitely try to adjust how I charge my devices.

Re: Powerwall 2 and Integrated Solar

#192

Post by pjc50 »

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…

I have a solar installation which makes it slightly harder to work out what I've actually used - I know what I've generated, and what I've paid for, but since the metering isn't net that doesn't quite let me work out actual usage.

I have however got a very nifty graph of my solar generation (3.8kW roof system, 56N Scotland): https://flatline.org.uk/daystats.html

What I think you can see if you poke about the graph is that solar is very variable in practice. There are days in summer when it doesn't break 500W at all, and in winter there's basically nothing for a couple of months.

I'm happy with the installation and its return in feed-in-tariffs, but I wouldn't consider going off-grid unless I had to and had space to put up a wind turbine.

Edit: my heating and cooking energy comes from mains natural gas, as well; currently this is far cheaper than electricity. Might be useful to include that in comparisons.

Re: Powerwall 2 and Integrated Solar

#193

Post by drcross »

espadrine wrote: post #177
Yaggo wrote: post #140

Earlier quoted context omitted.

We use heat pumps as well in Northern Europe, but to transfer heat from outside to inside. You can get even five times more heat for the invested electricity compared to direct (resistive) electric heating. The best winter optimized air-to-air pumps work down to -20 °C (-4 °F) with efficiency ratio over 1. For example, I heat my entire house with a single heat pump through the year. Our average electricity bill is ~1…

I heard great things about heat pumps efficiency-wise, but that their downside were noise. However, that information is dated because I haven't looked into it in a long time. Has that improved? I'd expect the market in Scandinavia to be much more developed than in my country.

I would also like to hear about heat pumps. A lot of information is either white papers or scienceless consumer information, with no middle ground.

Re: Powerwall 2 and Integrated Solar

#194

Post by Two9A »

gregn610 wrote: post #182

X-post from reddit as it might get an answer here... http://m.imgur.com/pgskG9q?r This LNG ship got me wondering about a battery equivalent, charged up in a desert solar farm and shipped to a major city. I get 16 Powerpacks per 40ft container 5100 containers per Panamax ship =81600 powerpacks per ship At 95kWh per pack = 7752MWh per ship ( based on powerpack v1) So is that like two Hinckley C nuclear reactors worth o…

Fully Charged interviewed the CEO of SunAmp recently: https://www.youtube.com/watch?v=9upXeTMHUqE

One of their new projects is to ship heat, stored in phase-change material, from a generation plant to central Bristol on a barge full of SunAmp cells. So it's a similar concept, shipping heat batteries instead of Powerpacks.

Re: Powerwall 2 and Integrated Solar

#195

Post by forgetsusername »

swampthinker wrote: post #4

Solar panel roofing tiles have been around for a long time. I wonder what this will do different? Pricing? Or perhaps they are relying on brand strength alone. Edit: I understand the urge to downvote because I'm not singing praise, but I promise I'm not trying to be overly pessimistic or critical of what Tesla is doing. Fact of the matter is, solar tiles have been done before, and failed miserably.

>but I promise I'm not trying to be overly pessimistic or critical of what Tesla is doing

The fact that you have to apologize for this on HN nowadays is hilarious. I agree. Both solar panels (and to a lesser extent solar roofing tiles) and the powerwall are have a lot of competition.

The idea looks good, though. I didn't catch pricing details in the presentation?

Re: Powerwall 2 and Integrated Solar

#197

Post by catawbasam »

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…

Our family of 4 in a 4BR house lives in the humid SE USA. We use about 5000 kWh/year. Our efficiency report says we use roughly half as much as comparable households.

Re: Powerwall 2 and Integrated Solar

#198

Post by sambe »

I'm not following the calculations, maybe I'm sleepy. "can power a two-bedroom home for a full day". They say that is 20kWh (it doesn't change when you say sockets vs entire home...). They say the battery is 14kWh and only recommend one. Huh?

Re: Powerwall 2 and Integrated Solar

#199

Post by pasiaj »

dabeeeenster wrote: post #162
dirtyaura wrote: post #147

Earlier quoted context omitted.

Interesting to compare different countries. Helsinki, Finland here. Roughly 2100kWh/year. 2 people, a flat with 2 rooms + kitchen. We have district heating. Several laptops in the house, frequent home cooking, most lights are LED based, no sauna inside the apartment. We don't pay any attention to manually saving electricity, i.e. turning off lights etc. Our electric company provides a comparison report on their web s…

'no sauna inside the apartment' Finnish problems

To give context: there are about 5,5 million Finns, and about 2-3 million saunas in the country.

Re: Powerwall 2 and Integrated Solar

#200

Post by maxerickson »

btian wrote: post #81
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.

For the price of a natural gas generator I can get 14kWh battery based storage and I can go off-grid if I want, that's terrific.

A $5000 natural gas generator can run an air conditioner as long as you like. A Powerwall might last an afternoon.

A $1000 generator will provide plenty of power to run everything other than HVAC.

Neither will get you off grid, but neither will a Powerwall until you spend a lot more on solar.

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