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Tesla Motors Announces a New Home Battery

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Re: Tesla Motors Announces a New Home Battery

#211

Post by engendered »

msandford wrote: post #203
engendered wrote: post #197

Earlier quoted context omitted.

It isn't just as valuable. Again, the wholesale market rate is significantly less than the subsidized tariff that they pay homeowners to feed back. To your final paragraph -- you essentially made up numbers and then demand that I refute them. 10. 14. 1.3e12. Refute that. The single and only reason this side discussion even happened is that I noted that some power companies will refuse to allow grid feed-in if you ins…

Did you even re-read what I wrote? Lead acid batteries cost about $100/kWh nameplate. But at 100% depth of discharge they wear out VERY quickly. We'll assume 50%. That means they cost $200/kWh in actual capacity. At 50% depth of discharge a lead acid battery will only get about 1000 cycles before it's not very useful anymore and needs to be replaced. $200 / 1000 cycles = $0.20 per kWh per cycle. That's the fixed cost…

Belligerent trolling? How utterly obnoxious.

You are inventing numbers from fantasy, and demanding retorts. What an astonishing bore, your inconsistent, incoherent point not in the least viable. Find a hobby.

Re: Tesla Motors Announces a New Home Battery

#212

Post by dm2 »

msandford wrote: post #190
engendered wrote: post #189

Earlier quoted context omitted.

And they'll achieve peak shaving in the process. Peak shaving is if you powered your own home off of your battery pack during peak times. The whole issue is that gamers -- who are essentially ruining "the commons" and pissing in the drinking well -- are instead abusing a system. Again, no home battery pack is helping the power company. The rates are hugely subsidized to encourage green energy. The people who abuse it…

You're right of course that it's not peak shaving, which is about shedding load. That was incorrect of me to state. But it is peak generation, which is just as valuable. > Again, no home battery pack is helping the power company. Please re-read my comment where I detail the economics of pulling power off the grid at low price and selling it back at high price is actually net-negative for the individuals doing so. Fro…

Peak generation... are you referring to Tea Time?

https://www.youtube.com/watch?v=UTM2Ck6XWHg

Re: Tesla Motors Announces a New Home Battery

#213

Post by Gravityloss »

IgorPartola wrote: post #114
jacquesm wrote: post #59

It's very hard to beat lead-acid on: - $/Wh - number of cycles - ability to be recycled at eol - loss of capacity over the lifetime of the battery (or beyond!) - safety It is easy to beat on - power density - weight - maintenance - mechanical stability (especially for fluid based cells) - installation cost (lead/acid requires a sealed enclosure venting to the outside to get rid of free oxygen and hydrogen) The same b…

Energy density is a big one. To store 5 kW * 24 hours (barely enough to power my house's essentials), I would need 286 of these ( http://www.amazon.com/VMAX857-Battery-Performance-minnkota-t... ). They are not small. Also, that would cost me nearly $32,000 in just batteries. My ideal setup for this would be something like 20 kW * 7 days. That would fill my basement pretty easily.

5 kW constant? Do you have the sauna on all the time?

Re: Tesla Motors Announces a New Home Battery

#214

Post by Sir_Substance »

dm2 wrote: post #209
Sir_Substance wrote: post #62

This still doesn't solve the essential problem with these batteries: They're about $20k each, and they only last about 4 years.

The Model S 85kW battery pack is estimated to cost $12,000 and is estimated to last 10+ years. The SolarCity Battery field-test uses 10kW Tesla batteries and is leased for $1,500 upfront and $15 per month. So, if the batteries degrade, it's Tesla/SolarCities responsibility to fix or replace them. The Gigafactory will likely reduce costs significantly. http://www.theverge.com/2015/2/13/8033691/why-teslas-battery... Es…

The list price for that pack according to these people is 44k.

http://www.greencarreports.com/news/1096801_tesla-model-s-ba...

It looks like you drank the tesla dealers coolaid:

http://my.teslamotors.com/forum/forums/tesla-model-s-85kw-ba...

Bad luck.

Re: Tesla Motors Announces a New Home Battery

#215

Post by sigkill »

brudgers wrote: post #201
SideburnsOfDoom wrote: post #44

Earlier quoted context omitted.

You can get energy out of a lithium battery several times, which puts it well ahead of tearing holes in the earth to mine coal. No, it's not permanently "off the grid" as it depends utterly on the whole industrial infrastructure, but it not continually tied to the grid like a power line running to a coal-fired power station.

TANSTAAFL. You can't get any energy out of a battery until you put energy in ... alas more in than out per the laws of thermodynamics.

Obviously TANSTAFL but the clear point here is you can burn coal only once. Solar panels + Li-ion can be reused atleast 500 times (assuming standard Li-ion batteries that crap out after 500 full cycles).

Re: Tesla Motors Announces a New Home Battery

#216

Post by dm2 »

Sir_Substance wrote: post #214
dm2 wrote: post #209

Earlier quoted context omitted.

The Model S 85kW battery pack is estimated to cost $12,000 and is estimated to last 10+ years. The SolarCity Battery field-test uses 10kW Tesla batteries and is leased for $1,500 upfront and $15 per month. So, if the batteries degrade, it's Tesla/SolarCities responsibility to fix or replace them. The Gigafactory will likely reduce costs significantly. http://www.theverge.com/2015/2/13/8033691/why-teslas-battery... Es…

The list price for that pack according to these people is 44k. http://www.greencarreports.com/news/1096801_tesla-model-s-ba... It looks like you drank the tesla dealers coolaid: http://my.teslamotors.com/forum/forums/tesla-model-s-85kw-ba... Bad luck.

This clearly states that the cost for a replacement 85kW battery will be $12,000.

http://www.teslamotors.com/blog/2013-model-s-price-increase

"We have received many requests for a Battery Replacement Option. We are happy to now offer this option for all three battery variants. This option will provide you a new battery anytime after the end of the eighth year at a fixed price. Prices are as follows: $8,000 for the 40 kWh battery, $10,000 for the 60 kWh battery, and $12,000 for the 85 kWh battery. You will be able to purchase this additional option through your MyTesla page in the near future."

I can't imagine that they would raise the price by 4 times. Where is the source for the $44,000 listed on the article you mentioned?

If there are 7,000 18650 batteries in a Tesla S battery pack and it's reasonable to assume that Tesla can produce (Gigafactory) these for $1 then the $12,000 seems perfectly reasonable. The current estimate for the cost of 18650s for Tesla is less than $2.

It's already been stated that the cost of a battery pack is less than a quarter the cost of the car, so the $44,000 is nothing but false. http://www.technologyreview.com/news/516961/how-tesla-is-dri...

Re: Tesla Motors Announces a New Home Battery

#217

Post by balabaster »

CamperBob2 wrote: post #179
innguest wrote: post #148

Earlier quoted context omitted.

It's BS as you rightfully detected but that doesn't stop the State cheerleaders above from giving us 1001 reasons why this is bad and we must protect the lives of electrical workers, firefighters, and even the lofty goal of protecting the hand-wavy "public commons" itself! Yeah, it's not the power company's fault for endangering the lives of their workers, it's our fault, you and I regular Joes, for daring to want el…

This doesn't make any sense. There are almost certainly provisions in the law for backup generators to be connected to the service panel with a transfer switch, either manual or automatic. The idea is that when the generator is powering the house, the powerline service is completely disconnected, and vice versa. This is standard stuff, part of every electrical code I've ever heard of. If a state legislature doesn't a…

Agreed

Re: Tesla Motors Announces a New Home Battery

#218

Post by jacquesm »

glabifrons wrote: post #210
msandford wrote: post #122

Earlier quoted context omitted.

Not necessarily! We don't know how deep the battery is being discharged. But we can make a guess. 4 * 365 = 1400 cycles. http://www.mpoweruk.com/images/dod.gif According to that chart (which is an approximation of course) 1400 cycles corresponds to about a 40% depth of discharge. Which isn't terribly shallow. The other variable is the discharge rate, and the higher it is relative to battery capacity the worse the eff…

I've wondered for years why people always gravitate towards Li-Ion cells when talking about a home storage battery. Li-Ion's advantages are far, far less important for a dwelling. Weight doesn't matter... you won't be moving them. Size doesn't matter nearly as much as it does in a vehicle... losing a few inches off an entire wall in a garage won't really be an issue for most people. Edison cells are incredibly durabl…

They may seem to be low tech but the electrodes are works of art and manufacturing them is a lot more expensive than a lead-acid battery of comparable capacity. They charge slower too, but they'll stand up to abuse better than every other rechargeable battery tech. I looked at them for a long time before settling on regular lead-acid, cost and finding an inverter that would charge these properly were the major factors.

Re: Tesla Motors Announces a New Home Battery

#219

Post by easp »

msandford wrote: post #116
engendered wrote: post #97

Earlier quoted context omitted.

>you can't even live 'off the grid' in a grid tied system I can't find any references for your stated claim about Connecticut, however it seems deeply illogical given that a generator (which surely aren't banned), solar panels, wind, etc, all have the potential of feeding energy back to the grid in an outage. Which is why there are regulations and home inspections and all of that, to ensure that the appropriate safet…

> where some users are trying to game the system by charging a big battery array during low cost hours, and then "selling" it back to the grid during peak hours (at inflated, subsidized prices). The idea that a utility wants a heads-I-win-tails-you-lose kind of situation is annoying at best and downright infuriating at worst. If they're willing to sell power for $X now and willing to buy it later for $Y, what does it…

The idea that some people fetishize disruption and heads-you-loose, tails-I-win situations baffles me. The utility has expenses beyond the cost of power generation. They don't exist to provide a subsidy to cool upstarts. They provide critical infrastructure for those cool upstarts and everyone else.

There are certainly a lot of perverse incentives and inefficiencies in the current model. Even so, its either ignorant, childish, or intellectually dishonest to act like it is outrageous that a utility has a simplified pricing model that doesn't accommodate the outliers among the outliers (residential customers with large solar and battery installations), or that their overall pricing allows margin for cost recovery and profit on power they deliver, whatever the source.

Re: Tesla Motors Announces a New Home Battery

#220

Post by easp »

jerf wrote: post #46
PanMan wrote: post #37

What would be the advantage of these LiPo batteries over traditional lead-based batteries? In car's, I understand weight (and volume) are really important, but for stationary usage these seem way more expensive / Wh stored?

I'm also curious about their lifetime. My laptop batteries are pretty weak after three or four years. It's much easier to justify $thousands as a one-time purchase than $thousands/year. For many of its applications, this is going to have to beat a generator. Which, come to think of it, probably means that if they're pitching this as a way off the grid it is precisely because it won't be even remotely competitive with…

For a given generation of lithium battery cell and management technology, there is the option of trading off between capacity and durability.

Field-replaceable laptop batteries are engineered as a consumable, and runtime, weight and charging speed are given priority over long life. Laptops with integrated batteries make a somewhat different tradeoff, but still assume that battery replacement will be a maintenance expense for some users. In both cases, the expected average lifetime of the laptop itself is also a factor, which I'd guess would be about 5 years, max.

Packs for laptops make different tradeoffs vs packs for a car, or home power storage. From memory, based on some back of envelope calculations, tesla trades 15-20% of nominial capacity of the cells in their auto packs for >=4x or greater durability. Packs for home energy storage would probably make similar tradeoffs, and might get more life with less aggressive charging rates.

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