Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Tesla Energy

teslamotors.com

Post reply on HN
Print view View original

551–560 of 590 posts

Re: Tesla Energy

#551

Post by [deleted] »

nine_k wrote: post #379
ams6110 wrote: post #345

Earlier quoted context omitted.

I would guess for most people it would show an ROI number that is not conducive to sales. Also, what is the environmental impact of the manufacture of LI batteries at this scale? Lithium mining, processing, assembly, delivery... we can't just ignore that.

Lithium mining has relatively little environmental impact: it's mostly evaporation of lithium-rich brines. But lithium is still not cheap. I suppose that a different battery technology, with lower energy density per unit of weight, could be much cheaper with comparable efficiency. But Tesla only has expertise in lithium batteries, so some other manufacturer could use the momentum with a lower-cost offer.

[deleted]

Re: Tesla Energy

#552

Post by mikeash »

alkonaut wrote: post #510
voodoomagicman wrote: post #413

Earlier quoted context omitted.

The battery costs $3000 - that is likely a cap on the cost of the work involved in producing it.

You'd think, but that depends on how many times you can sell the same battery. As others have said, it's plausible that this is a way for Tesla to make use of used car batteries.

I really doubt that's true, just because it's too early for it. There are approximately zero used Tesla batteries available right now. The fleet is just too new. Maybe in another ten years.

Re: Tesla Energy

#553

Post by parasubvert »

rhino369 wrote: post #500
billions wrote: post #464

Earlier quoted context omitted.

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.

Doesn't Telsa already sell a product like that?

The home charger cable is capable of 240V/80A (20 kWh) connections.

Superchargers are around 363V/225A (90 kWh) but supposedly capable of 120 kWh.

http://www.autoblog.com/2013/02/01/hands-on-with-the-tesla-s...

So you're looking at 3 hours at home vs 45 minutes at a supercharger for a full charge. With the 10 kWh wall charger you might be able to cut 45 min off a home charge.

Re: Tesla Energy

#554

Post by warfangle »

dragontamer wrote: post #528
warfangle wrote: post #486

Earlier quoted context omitted.

A venting lithium ion battery isn't usually an electrical fire.

And what of all the molten wires that _were_ charging said battery?

Overcharging a battery isn't the only way to cause it to vent :)

Obviously there should be a physically separate circuit for cutting off power in the event of catastrophe. That's pretty much rule-of-thumb for large li-ion battery banks.

Re: Tesla Energy

#555

Post by URSpider94 »

bryondowd wrote: post #327
URSpider94 wrote: post #133

Earlier quoted context omitted.

I could do this today. With my current time-of-use electric rate, I pay an average of $0.25/kWh more for peak power than I do for off-peak [the differential is larger in the summer, smaller in the winter]. If I shift 8kWh per day, then I would generate positive ROI in less than five years. Your edit is spot-on. Utilities typically use natural gas "peaker" plants to meet mid-day spikes in demand, while nuclear plants…

Is 8kWh/day realistic? I'm curious, honestly wouldn't know. Seems like that would be charging and discharging 80% of the 10kWh battery's capacity every day. Would that affect lifespan? Also, it would seem to render the device less useful as a battery backup system during most of the day, since it would be mostly depleted.

My home uses about 1000 kWh per month, so shifting 8kWh per day of my in-house demand is feasible. However, there's really no correlation with my usage, since I can just push and pull that power from the grid, as if I had a solar or wind generator.

Lithium batteries are fairly tolerant of deep discharge, but yes, I would expect that the pack would be worn out after max 7-10 years if used like this.

Yes, using the pack like this would make it much less useful for battery back-up, but where I live (SF Bay Area), I haven't had an outage that lasted longer than 2 hours since we moved into our house, and this would cover the basics (probably everything but A/C) for that time. You could always split the difference, for example using 4 kWh per day -- this would pay still give you 6kWh+ of backup power and let you get the battery at half off or better.

Re: Tesla Energy

#556

Post by andor436 »

analyst74 wrote: post #549
andor436 wrote: post #471

Earlier quoted context omitted.

I also live in Michigan, and can tell you it will be a money loser for one major reason: the full cost of the system you install will be added to your local property tax valuation, as the state tax exemption on renewable energy equipment was nullified several years ago and never replaced. In my case I had $500 in taxes added to my annual bill, which outpaces the value of the energy I produce and creates an infinite p…

Does that mean when you sell your house, you will recoup the cost of the system? If that's the case, the system itself wouldn't be a non-refundable investment, and calculating ROI on it would be as silly as calculating ROI on your house.

Good point. It's unclear to me though. In some places (Hawaii, California, Germany) where there's huge acceptance of renewables and much shorter payback periods I believe a PV system would add value to a sale. Here in Michigan it's much less clear - plenty of my neighbors think it's ugly and an eyesore, or are somehow opposed to the whole concept. So I am pretty sure in the end it's a net zero here (no pun intended!)

Re: Tesla Energy

#557

Post by Dylan16807 »

kragen wrote: post #507
sswaner wrote: post #330

Earlier quoted context omitted.

Have you ever tried to bake in a solar oven? In anything less than ideal solar conditions baking either fails completely or takes a long time.

I admit that I haven’t! However, I think you’re talking about baking in a crappy solar oven, not baking in a solar oven in general. For example, http://www.solare-bruecke.org/infoartikel/Papers_%20from_SCI... describes a 3.4m² kilowatt prototype solar oven successfully used to cremate chunks of goat meat at temperatures of 800° to 900° in under an hour. Larger solar ovens (usually known as “solar furnaces”) can reach…

I could use an exotic molten-salt-backed oven, or I could pop in a third battery pack for $3500.

Re: Tesla Energy

#558

Post by DaniFong »

robot wrote: post #493
DaniFong wrote: post #492

Earlier quoted context omitted.

Wright brothers: focus on wings or controls or engines! you only have room for one! Apple: focus on hardware or software! Macs or iPods. You only have room for one. Edison: focus on lights or electricity! You only have room for one. Uber: focus on the driver network or the app! You only have room for one. It's not a hard and fast rule. The point of focus is to get you to prioritize what important, but something you n…

The problem with all of your examples is they still only sell one thing. Tesla now sells 2 things. That means sales, marketing team, strategy, support, for 2 things. Like, having 2 companies.

Another example, Standard Oil: don't just sell the oil. Refine it, and sell the kerosene, and the lamps, and also sell the gasoline, and when you're left with paraffins invent paraffin candles and sell those too...

Re: Tesla Energy

#559

Post by giarc »

edwhitesell wrote: post #526
giarc wrote: post #515

Earlier quoted context omitted.

I doubt many homes would have adequate fire separation between a garage and main home to make a difference between laundry vs garage.

It may not make much of a difference from the overall perspective of damage, but it certainly makes a difference in warning and escape time. Also, the chance of dangerous fumes while trying to escape is lower.

Depends on design. Garage could share a wall with a bedroom and the laundry could be on other side of the house or vice versa. I would say that garage may be the most obvious choice, but not always.

Re: Tesla Energy

#560

Post by JoeAltmaier »

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.

I live in Iowa. It gets to -20F some days in winter. This thing stops working at -4F. So inside is My only option.
Post reply on HN