Tesla Energy • Hacker News Board

Re: Tesla Energy

#181

Post by miratrix » Fri, May 01, 2015, 7:34 AM UTC

ChuckMcM wrote: post #138

Nice, that came in lower than I was expecting. I was thinking $5K for the 7kWh unit. Of course that is the "installers" price so who knows what those folks will consider the 'retail' price. My wife still has her solar installer certification so we could presumably get one that way. It also makes for a really interesting opportunity for grid tied solar inverters. Now you want the inverter to power the house first, the…

On the grid tied solar inverter front - the spec sheet says the battery voltage is 350~450 V, so we're looking at 108 lithium ion cells (25 x 18650 cells?) at 400 VDC nominal. This is quite different from typical lead acid battery pack voltage of 12, 24, or 48VDC that's used for battery backup storage, so a lot of existing solar battery storage infrastructure may not even work... this means that people may need to buy a whole new set of supporting hardware to integrate this into the existing solar systems instead of being able to update the software on existing hardware.

Lithium Ion also has quite a different (and much less forgiving!) charging cycle that requires much more monitoring of things like temperature, though I'd imagine a lot of that would be built-in as a safety mechanism directly into the Powerwall.

What I've heard is that National Electrical Code becomes much more stringent on battery systems greater than 48V, with the line drawn at 48V due to it being used widely in the phone landline system. I'm not sure how true that story is, but I'd imagine extra care is probably warranted. 10kWh is about 9kg of TNT. :-)

Re: Tesla Energy

#182

Post by yakuzanobu » Fri, May 01, 2015, 7:35 AM UTC

spiritplumber wrote: post #79

Funny that something called Tesla Energy brings back direct current to the home. I wonder how many people will catch that.

Or Tesla laughing from beyond the grave at the fact that a company named after him is getting the credit for bringing DC to the home?

Re: Tesla Energy

#183

Post by yason » Fri, May 01, 2015, 7:36 AM UTC

ChuckMcM wrote: post #138

Nice, that came in lower than I was expecting. I was thinking $5K for the 7kWh unit. Of course that is the "installers" price so who knows what those folks will consider the 'retail' price. My wife still has her solar installer certification so we could presumably get one that way. It also makes for a really interesting opportunity for grid tied solar inverters. Now you want the inverter to power the house first, the…

But you might not want someone to vandalize or steal the battery either which can happen if it's outdoors. Maybe it would be best to put it in a separate shed with lock or something.

Re: Tesla Energy

#184

Post by ekianjo » Fri, May 01, 2015, 7:37 AM UTC

rdl wrote: post #179

ekianjo wrote: post #178

Great, except that all these nice batteries are produced with extremely toxic processes, involve heavy metals, and consume a whole bunch of fossil fuel during their production. Hardly a good case for the environment when you factor everything together.

Lithium-Ion batteries aren't all sweetness and light, but it's not a particularly dirty process compared to Ni-Cd, and certainly you have to factor in benefits of reduced generation.

> have to factor in benefits of reduced generation

Well the outcome really depends on how long they last before you need to replace them. Plus you have the take in account the recycling cost (for the environment as well).

Re: Tesla Energy

#185

Post by will_hughes » Fri, May 01, 2015, 7:38 AM UTC

CamperBob2 wrote: post #161

TaylorAlexander wrote: post #109

Earlier quoted context omitted.

People say that, but from what I've heard there is plenty of lithium in the world to increase use 20% every year for 30 years before we need to get more creative in how we mine it. That's a huge total increase and means that electric cars totally are scalable. Do you have information supporting the idea that electric cars aren't scalable? My understanding is that they definitely are scalable.

Charging is where the scaling problems come in. If everybody in your neighborhood plugs in their Tesla at their home at night and/or at their office during the day, it will likely cause brownouts and blackouts in areas with grid service that's already marginal for current demand. Hence Musks's interest in load-shifting technology.

Utilities have existing techniques for distributing that load. They already work with smelters and other large power users to coordinate their power demands.

In some places utilities are offering discounted electricity prices if the car charging infrastructure is hooked up to their smart metering/control system. This allows the company to signal when cars should start/stop charging.

There's no reason they can't work with car makers to introduce two way signalling between the charging infrastructure and the grid - the car can tell the grid that it needs to use X kW by Y time, and the grid can communicate the current permitted load.

Potentially with some option for the customer to pay a premium to charge immediately at a higher rate.

Re: Tesla Energy

#186

Post by will_hughes » Fri, May 01, 2015, 7:39 AM UTC

ChuckMcM wrote: post #138

Nice, that came in lower than I was expecting. I was thinking $5K for the 7kWh unit. Of course that is the "installers" price so who knows what those folks will consider the 'retail' price. My wife still has her solar installer certification so we could presumably get one that way. It also makes for a really interesting opportunity for grid tied solar inverters. Now you want the inverter to power the house first, the…

Outdoors you're going to need to heat and cool it more - you want those cells kept within a fairly narrow range to keep the lifespan up.

Re: Tesla Energy

#187

Post by will_hughes » Fri, May 01, 2015, 7:42 AM UTC

GigabyteCoin wrote: post #167

frakkingcylons wrote: post #5

A notable beta user: AWS will be running a 4.8 megawatt hour pilot program with Tesla's batteries in the us-west-1 AZ (Northern California). Hopefully this allows AWS and other hosting providers to use intermittent, renewable sources of energy more often. EDIT: I'm guessing AWS will be using a cluster of 48 power packs (100 kilowatt hours each).

This might be a reason to move your production environment out of us-west-1 for a few years. I wouldn't want any experiments going on around my main servers.

I imagine that these are on the grid side of their existing UPS/Generator systems, rather than part of it.

Re: Tesla Energy

#188

Post by eatmyshorts » Fri, May 01, 2015, 7:46 AM UTC

colinsidoti wrote: post #51

One thing that might go overlooked: Load shifting could, in theory, lower electric bills such that there's ROI without solar panels. --- Edit for why: On-demand power is expensive. "Spinning up" additional power during the day is more expensive than having certain types of power generation running all the time. In theory, pumping power into a battery at night during non-peak hours will cost less than consuming direct…

Yep. This is targeted at ERCOT as much as it is targeted at the home consumer.

http://www.greentechmedia.com/articles/read/Bring-on-the-ene...

Re: Tesla Energy

#189

Post by tarmigan » Fri, May 01, 2015, 7:47 AM UTC

(Posting from my phone after the event). If you are excited about this and want to work on it then please email me at tcasebolt@teslamotors.com. We are very excited about the technology and future!

Re: Tesla Energy

#190

Post by tarmigan » Fri, May 01, 2015, 7:47 AM UTC

(Posting from my phone after the event). If you are excited about this and want to work on it then please email me at tcasebolt@teslamotors.com. We are very excited about the technology and future!