Tesla Energy • Hacker News Board

Re: Tesla Energy

#461

Post by Florin_Andrei » Fri, May 01, 2015, 5:37 PM UTC

IanCal wrote: post #212

roel_v wrote: post #197

Earlier quoted context omitted.

" 4kW seems to be the maximum potential drain from the battery. That wouldn't power an oven… let alone anything else at the same time." 4kW is enough to power an entire home continuously, without thinking about energy use, even a large one with a home office with several people working in it + washing machine + oven + electrical stove at the same time . I have the data to prove it, too - 10 second interval power cons…

> I never had a load of more than 3.5kW Different issues over the pond, my kettle can draw 3kW :) Since so many of my countryfolk have something similar, this actually causes our energy production quite severe issues when popular TV shows finish. Often a 200-400 MW spike but at the end of the 1990 world cup semi final penalty shootout against Germany, there was a spike of 2.8GW. An interesting example of some of the…

> my kettle can draw 3kW

Pretty awesome for when you want that coffee ready in like 30 seconds flat, huh?

Re: Tesla Energy

#462

Post by butwhy » Fri, May 01, 2015, 5:38 PM UTC

KhalPanda wrote: post #417

For those interested in investing and finance, I have a question. Why would this news not cause Tesla's share price to go up? It seems generally well-received (well, as much of an indicator as 812 points on HN is). Surely that's a good sign? Or did the announcement not live up to the hype, causing people to dump stock?

Buy on the rumour, sell on the announce. Sharetrading 101.

Re: Tesla Energy

#463

Post by hammock » Fri, May 01, 2015, 5:43 PM UTC

NickM wrote: post #449

edwhitesell wrote: post #382

Earlier quoted context omitted.

I have the opposite problem: Living in Texas, my garage easily gets above 110F many days during the summer (it would be crazy to pay for A/C in it). But, I'm also not going to put the battery pack(s) "inside" my house (e.g. utility/laundry room).

But, I'm also not going to put the battery pack(s) "inside" my house (e.g. utility/laundry room). Why not? The whole point to making it wall-mounted is that it won't take up any substantial amount of space. A utility/laundry room seems like exactly the logical place that you would want to put it.

Fire hazard

Re: Tesla Energy

#464

Post by billions » Fri, May 01, 2015, 5:43 PM UTC

rhino369 wrote: post #454

ZoFreX wrote: post #261

This is a three-pronged stroke of genius: 1) Immediate benefits to just about anyone. If you have your own solar panels, you need this (or something like it). Even if you don't, you can benefit by drawing more power during cheaper off-peak times. 2) If lots of people get in on this, we'll have the storage capacity we need on the grid to be more dependent on renewable energy. Lack of storage capacity is one of the big…

1) You don't need this if you have solar. Most states and utilities have pretty favorable subsidies for "selling back" energy to the grid. The utility is credit the feeding back to the grid at 100%. This device will introduce efficiency losses and it is expensive. Unless you have extreme peak v. non-peak fees, I doubt this will save you money. Even at 20 cent difference, 7kW hours is a 1.40 a day. But that assumes th…

I see this product targeted at current tesla owners. A PowerWall driven supercharger in-house could reduce charge times by 80%. Today's 10 hour charge time is a huge inconvenience compared to a 10 minute gas station run.

Re: Tesla Energy

#465

Post by toomuchtodo » Fri, May 01, 2015, 5:43 PM UTC

eru wrote: post #201

toomuchtodo wrote: post #110

Earlier quoted context omitted.

> utilities would quickly erase any peak-vs-non-peak arbitrage opportunities. Probably right around the same time they're no longer necessary, as the cost of distribute solar continues to plummet. Its actually truly amazing how quickly the price continues to drop for panels each year.

Depends on country. I doubt you could ever run, say, Germany or Britain on locally produced solar power.

But you could run it on a combination of onshore wind, offshore wind, distributed solar, utility solar, and energy storage (ie Tesla's Utility Storage solution).

Re: Tesla Energy

#466

Post by dpark » Fri, May 01, 2015, 5:44 PM UTC

TeMPOraL wrote: post #388

Shivetya wrote: post #248

Earlier quoted context omitted.

it isn't so much how many people charging, its the ability of people to charge where they live and the lack of ability to truly quick charge the battery. As in, damn the kids left the car unplugged and I have to work. even thirty minutes at a super charger is not a good solution. So it comes down to a compromise, a good range extender technology and batteries for the majority of driving. That until truly faster charg…

> As in, damn the kids left the car unplugged and I have to work. even thirty minutes at a super charger is not a good solution. I don't see this as something to worry about - it's just a household habit problem. Pretty much every new device introduces some, and people quickly adapt to use the device properly.

The argument is silly. The kids could also forget (or just not bother) to put gas in the car and leave it on empty. Yet strangely we manage to make do with gas-powered cars.

Re: Tesla Energy

#467

Post by chrisamiller » Fri, May 01, 2015, 5:46 PM UTC

bloaf wrote: post #453

chrisamiller wrote: post #431

A quick analysis of our local (St Louis) rates for an average (1700 sq ft) suburban house indicate that time shifting to get peak rate savings isn't worth it: Payback time on the 10kWh battery would be around 26 years, and on the 7kWh battery would be 33 years. So, at least in the midwest, I think you'd have to be either using a ton of peak energy or coupling the battery pack with solar to make the investment worth i…

Isn't that the idea though? Solar + battery + electric car = no gasoline, electricity, or natural gas bill. If the average car gasoline bill is $3000/year, electricity is $1000/year, and we demand a 5-year payback, we can spend at most $20,000 on a solar+battery+car system over what we would spend on a conventional gasoline-car and grid-house.

Yeah, that's the primary use, but there has been speculation here and elsewhere that a battery could be worthwhile just for exploiting the difference between peak and off-peak rates. This indicates that, at least for my area and usage, the answer is no, it's not worth it.

Re: Tesla Energy

#468

Post by danans » Fri, May 01, 2015, 5:46 PM UTC

willholloway wrote: post #286

Animats wrote: post #195

The wall mount surprised me, but 10KWh at the same density as the Model S battery should be only 155lb. That's not too bad, although you need a solid connection to the building structure. Having it above floor level is a good thing, since it won't be shorted out by minor flooding. If you get a new solar installation, installing one of these seems an obvious win. The solar installation already includes the inverters a…

As I've learned more about heat pumps I've been wondering why we all use air-source cooling for central A/C. We are cooling our condensers with hot summer time air when the temperature is much lower just four feet under the yard. The energy requirements would drop way down by cooling the condenser with a water ground loop. Ground loops are seen as expensive for installation, but I don't understand why. It's just plas…

I very briefly looked into this. It seems to be the same reason that simple and obvious things like solar water heating systems are so expensive in the US, but not elsewhere: Lack of awareness & low demand but few installers who target the eco/luxury niche product at a high price. These systems usually get installed only in high-end homes.

Re: Tesla Energy

#469

Post by saryant » Fri, May 01, 2015, 5:46 PM UTC

Thiz wrote: post #308

I predict Venezuela will be the biggest importer of powerwalls to cope with daily outages. Who knew oil-rich but impoverished countries would help fuel innovation.

Venezuela has almost no dollars. They don't have the money to import toilet paper much less multi-thousand-dollar battery installations.

Re: Tesla Energy

#470

Post by sfrigon » Fri, May 01, 2015, 5:47 PM UTC

uberdog wrote: post #406

sfrigon wrote: post #312

Earlier quoted context omitted.

Living in a region with cold weather, this is the kind of situation I would like to solve too. The problem is that a generator still has benefits over a battery, it can be refilled (i.e. when you lose electricity for a longer period).

Having lived through Hurricane Sandy in NYC: don't assume you can get gas to fill your generator in a disaster situation. Solar panels paired with a battery aren't dependent on a supply chain (that itself needs energy).

Yes, getting energy from a sustainable source of energy is the best way, but assuming you only use it for power outages once or twice a year, I am not sure it is worth the investment. Especially if you expect it to last a day/few days (if you are self sufficient for a few days you'd better do it all year long).