Mar 9, 2011
benji4 Still less than in Europe or Japan though even at $6.52!�
Mar 9, 2011
Todd Burch Whuh oh. All of this is making that 300 mi pack look better and better. Might have to do some convincing of my other half...�
Mar 9, 2011
Iz Good analysis Todd. I find myself in a similar position. The 300-mile pack is a stretch from a $ position.
In addition to the long-term fuel savings we should also factor in parts & maintenance not required for an EV. Conversely, have to add in the cost of a charger, if planning to use level II at home.�
Mar 9, 2011
ckessel To make a fair comparison though on fuel costs, the costs for electricity to charge should be included as well as similar analysis of rising electricity rates over the years. Granted, it's going to favor EV's by a big margin, but it's still relevant if we're talking total cost of transportation.�
Mar 9, 2011
Doug_G On the other hand, gas prices are likely to be even more volatile and on an upward swing. Peak oil production will guarantee that, even if unrest in the middle east doesn't.�
Mar 9, 2011
ckessel For me, as much a stretch as the 300 mi pack might be, I think it makes the most sense. As the article dpeilow noted, the cheapest range/$ is with the 300 and even if I don't need 300 now, the 300 gives me the longest level of use before degradation would force me to buy a new battery. At the 230 level, getting near 70% capacity starts being a real issue for day trips to the coast or to my parents place 2 hours south. With the 300, I could avoid fully charging in range mode and have only 70% after degradation and still likely have the range I'd require most of the time. It might very well last me until fast charging infrastructure is in place, in which case my need for serious range drops even further. There's the very distinct possibility an initial 300 mile could last me until it's ability to hold a charge just completely falls off a cliff.�
Mar 9, 2011
Todd Burch Personally, I'm just planning on using my 240V outlet that's already in my garage, which I think is 15A(?). That gives 240V * 15A * 85% charging efficiency = 3.06 kW. If I drive 80 miles a day, that's 345Wh/mi * 80 mi = 27.600 kWh per day...which would require 9-ish hours of charging...something I can easily do overnight almost every night. If I can't, then I have that big battery as a buffer.
If I find a need I can always get a charger later, but I'm having a hard time envisioning scenarios where I'd need it.�
Mar 9, 2011
Todd Burch In my numbers, I bumped my personal electricity cost by 25% from its current value as an estimate...not sure how accurate that is, but I did at least consider it. I think it won't make a huge difference in the end...the majority of the cost is from the battery itself, not the electricity.�
Mar 9, 2011
drbradfo Your 240V outlet is likely a 30A circuit for a dryer. So you can chop the charge time in half.�
Mar 9, 2011
bolosky I think that we're all missing an important point with regard to the battery pack degradation. Degradation is due to two things: calendar life and use (and environmental conditions, but I'll just assume those are constant and ignore them). The calendar life effect depends just on the battery chemistry while use depends on the number of cycles of a given cell.
It's the last point that's important here: if you've got a 300 mile battery and you drive it 100,000 miles, then you've used 333 cycles of the battery. Do the same thing with a 160 mile pack and you've used 625 cycles. Therefore, you'd expect the use part of the degradation to be nearly twice as large on the 160 mile battery than on the 300.
Put another way, I think that it's wrong to say that at 100,000 miles you'll be at the same percentage of the battery capacity regardless of the pack size. You'd expect the percentage loss to be smaller (by less than a factor of 300/160) for the 300 mile pack than for the 160. How much less depends on the relative contribution of calendar age to the capacity loss.
Taking a complete wild guess at it, if we say that half of the loss is calendar loss and half is due to use, and say that the 70% after 100K miles for the Roadster battery also hold for the model S if it had a 244 mile battery, then we see that 410 cycles (= 100,000 /244) is 15% loss (half of the 30% overall loss), so the use loss rate is about 0.0366% per cycle. The 300 mile battery after 333 cycles then would be at ~73% (219 mi), while the 160 mile would be at 62% (99 mi).
This makes the argument for the 300 mile battery a little stronger. Of course, how much stronger depends on the relative contribution of age and use which I just completely made up in the previous paragraph. It also may vary based on the different cells used in the 160 and 300 packs, though IIRC the 160 and 230 packs use the same cells, just more of them in the 230 so it should really be linear there.�
Mar 9, 2011
Todd Burch Bolosky: True, degredation is largely an effect of cycles used...For a constant daily drive distance, the 160mi pack will degrade faster. But now we're starting to get into the gray area where we don't have enough use data--so I just stuck with Tesla's estimate of 70% at 100K miles. But you're absolutely right--cycle use does tend to push toward the argument of the larger battery.
Although I'm not sure if it's a big difference...230 mi vs. 300 mi differs by 3% in your estimate.
Hopefully Tesla will put a lot of this kind of info out there in the coming year to help us all make our battery size vs. wallet size decision easier. Uncertainty (and that $20k upgrade) is the price we pay for adopting new technology I guess...�
Mar 9, 2011
ckessel I've no idea how battery use works internally, but this relies on an assumption. If I drive 100,000 miles and plug in every night, the number of times I charge is the same as is the length of charging time regardless of battery size. The 160 battery is closer to empty than the 300 each night, but it's not clear to me whether degradation is a function of how many times you charge vs. how empty the batteries are when you charge.�
Mar 9, 2011
bolosky Yes, it does assume that. My source for the assumption is comments that Tesla made about battery life, which I didn't manage to find in the two minutes I put into searching for it.
Of course, it's only roughly true. Draining your battery all the way down to zero is harder on it than taking it to 20%.�
Mar 9, 2011
Doug_G "Charge cycles" is a bit misleading, in that it implies you fully drain then fully charge the battery. That's not how they are used most of the time. A more appropriate measure might be how much total charge you put into the cell over its lifetime.
Also it's not just charging. Just sitting idle the battery slowly loses capacity; the higher the temperature the worse it is. It also shortens the lifetime if the battery is fully charged, which is why Standard mode only charges to 90%.
This all makes me feel better when I have to put my Roadster in storage mode during the worst of the winter. It's sitting in the cold with half a charge. Hopefully my battery will last longer than average. Of course my Model S will be used year 'round.�
Mar 9, 2011
vfx So when considering a 300 mile battery are you thinking you will do a Range Charge (all the way full) every time? AND drive the full range distance each of those times? Doubtful. Doing so will degrade the battery. We all have our occasional long 250m trip but the majority of us charge in standard mode the majority of the time.
Why keep an EV car battery topped in range mode "just in case" at the expense of battery life? Anyone here do that? These real world charging profiles should be figured into battery life calculation cycles.�
Mar 9, 2011
bolosky No, of course not. That would be foolish. What I'm saying is that one component of the degradation of the battery is the amount of energy that's come out of it. As long as you don't push it too close to completely full or completely empty or run it outside of its temperature range, it doesn't matter if you go from 90%-10% 10 times or from 90%-80% 90 times, it's about the same effect on the battery. Given that, then the larger batteries will last longer than the smaller ones because the same distance travelled is less of a load on the cells, since they're bigger (and in the case of the larger batteries vs. the 160 more numerous).�
Mar 9, 2011
benji4 Probably nobody does that, but taking that same argument, the 160 mile battery doesn't seem like enough for any serious driving. Charge it in normal mode and perhaps you get 130 miles ideal range, and a bit of spirited driving maybe gets you down to 100. So you are almost starting to get down into LEAF territory there. The 230 mile pack is right in line with what you get with the Roadster and it seems like it might be hard to be happy with less than that especially if you already drive a Roadster.�
Mar 9, 2011
dsm363 You could always upgrade that to a 50A outlet as well. Shouldn't be too hard or expensive to do since most of the wiring is probably already there.�
Mar 9, 2011
donauker My typical standard mode range with snow tires and cold weather this winter has consistently been between 110 and 120 miles. I couldn't imagine life with a 160 mile pack.�
Mar 9, 2011
ckessel I wonder if the government will eventually require better EV range disclosure. Like the city/highway stuff for MPG, EV would have to display something like 100/160 for typical/ideal.�
Mar 9, 2011
benji4 Yes, really seems like the $10k jump from 160 to 230 is pretty much a neccessity unless the car is really just used around town. But then it's just another $10k from there to get to 300, so..... I'd wager that most people opt for the 300 mi pack. I think it's like the difference between the Roadster and Roadster Sport. "Well, it's only $20,000 for that extra 0.2 sec. off the 0-100 time, and sometimes I like to accelerate quickly, so...". And people end up buying the Sport. The marketing people at Tesla are sure clever, and that's a good thing because I'm sure we all want them to stay in business!�
Mar 9, 2011
kvietor Suck it up guys. :biggrin: Its still almost a year and a half away. The price is a little steep, but I've been socking away as much cash as possilble. A few less trips to Dunkin Donuts, a couple more garage sales, and well hell, the grandkids can wait another year or two for their college funds. lol
Seriously tho... I can't wait to get mine. And I'll do whatever it takes. I'm just glad the wife is onboard with this. I know it'll never pay for itself but I can't wait to snub my nose at the oil companies.�
Mar 9, 2011
stopcrazypp In case there is still confusion about calendar life vs. cycle life, I'll try my best to clarify.
Calendar life: the life of a battery measured in time (even if you don't use it and just store it).
This depends on average temperature and state of charge (SOC). The higher these are, the shorter the calendar life (caveat: some chemistries are less affected by SOC and have wider operating temperature ranges). This explains why "Storage Mode" in the Roadster is at lower SOC and why Tesla packs have liquid cooling to keep the battery at 25C. Tesla quotes calendar life at 7 years for the Roadster; I would expect the same for the Model S since it will use similar cells.
Cycle life: the FULL cycles a battery can last using 0-100-0% cycling @ 25 Celsius & 1C discharge (1C means using 1 hour to fully discharge the battery, 0.5C means using 2 hours, etc.)
This means cycling 0-50-0% two times is still counted as one full cycle, not two. Put another way, charging 0-50-0% only counts as half a cycle. However, the impact of charging partial cycles at lower max SOC is less than cycling 0-100-0% all the time (this is related to the calendar life part, where you want to keep average SOC over the life of the battery low). That is why Tesla has a "Standard Mode" (~10-90%) and why the Leaf offers a "80%" mode that is used during typical charging.
The relevance to the Model S is that since lithium cobalt 18650 batteries have a cycle life of ~500 cycles, you can easily estimate expected life in terms of miles using 0-100-0% cycling:
160 = 160miles/full cycle * 500 full cycles = 80,000 miles
230 = 115,000 miles
300 = 150,000 miles (**note: this pack uses different & newer chemistry so this estimate may not apply**)
You may get better than these numbers if you mainly charge in Standard Mode or even Storage Mode. You may also get better than these numbers if your average discharge rate is lower than 1C. Both will be easier to do with a larger battery pack.
End of life (EOL): Different manufacturers will define it differently, but according to Tesla, the industry generally defines it as 70-80% capacity left.�
Mar 10, 2011
AnOutsider Thanks for that crazy, cleared a lot up. Now the debate can begin again with fresh perspective haha�
Mar 10, 2011
Kevin Harney No not really the LEAF is the 100 mile equivalent of the Model S 160 mile pack so in normal mode it would get 75 miles and with spirited driving (if that is possible in a LEAF LOL) probably down to 50 miles .... Make apples and apples comparison.�
Mar 10, 2011
benji4 Okay, point taken, but I did say "almost starting to get down into LEAF territory", so not quite a direct comparison. I'd take the 160 mi Model S over the 100 mi LEAF any day of the week! I just think that if somebody has $60,000 to spend on car already, may as well cough up another 10K to get all kinds of huge benefits. The difference between the 160 and 230 pack is a REAL 70 miles, plus more power, plus a lot longer life. Way better investment than a $10,000 exterior carbon fiber accent package!�
Mar 10, 2011
mattjs33 Wow, just read through this thread, and now my head hurts. Too much math. You guys are serious about this stuff.
What occurs to me with all this number crunching is that there are some who are desperately trying to come to terms with and justify a 300 mile Model S at very near $80,000 before taxes and Tesla's notoriously expensive options. Don't forget, the $7500 is a TAX CREDIT, you still have to pay full price. Funny how people distort that into reducing the price of the car.
And the 160 mile option will not be available at launch, so I guess those reservation holders will have to pony up more dough or wait longer for their cars?
The Model S might very well be a great car and perform exactly as promised, but it's clear that a Tesla will remain, for the time being, a plaything for the wealthy.�
Mar 10, 2011
Eberhard The solution is very simple: Invest today $50.000 in Tesla stock. If the Model S is as successful as i believe. In the time, the Model S is on public roads and available for delivery, the share price will skyrocked. With the profit, you can easily buy the Signature Edition.�
Mar 10, 2011
benji4 Well, the Roadster might be considered a plaything for the wealthy, but the Model S is an incredibly functional car for the pretty wealthy.�
Mar 10, 2011
benji4 Excellent idea! And if you are wrong and the investment halves... you can still pick up a new Prius for 25k!�
Mar 10, 2011
vfx Good point the car taxes are significant. Though others have pointed out that they simply structure there finances to make sure they have that $7,500 deduction.
As I mentioned above states like California (for now) add an additional $5,000 (that comes as a check) for full buying full-electrics
Roadster owners get another $10,000 discount on the S
Other states have different discounts like no DMV fees and HOV driving which see as a time=money discount.�
Mar 10, 2011
ckessel Unless you're paying cash out of pocket for the car, it's a somewhat irrelevant distinction. I'll get an extra $7,500 on my car loan, then dump the $7,500 against the car principal when the tax refund hits. All I lose is the interest on that $7,500 for however many months it takes to get the tax refund.�
Mar 10, 2011
Sparrow Maybe getting off topic, but isn't the $7,500 Tax Credit subject to the Federal Alernative Minimum Tax and thus some people might not get all or any of the tax credit for the purchase of a Roadster or S?�
Mar 10, 2011
donauker No it is not subject to AMT.�
Mar 10, 2011
donauker Wow, didn't know this. Is this in writing anywhere?�
Mar 10, 2011
mattjs33 I see what you are saying here, assuming the refund is put towards the car. I'm sure lots of people would be tempted to use it for other things, like they typically do with their refunds.
For a person in the financial position to spend nearly $100,000 on an automobile, the tax credit is probably not only irrelevant, but ridiculous. At a lower price point, however, it becomes very relevant indeed. Tesla is by far the only one guilty of this marketing tactic. Chevrolet, Nissan, Think, Wheego, CODA, are all saying that their car is X dollars after the federal rebate. For an average buyer looking to take the plunge into an electric car in that price range, the $7500 has a big effect in whether they can even get the financing, and what their monthly payment will be. So they will be told the bottom line price is X, when they have mentally been figuring a lot less. Yeah they get the tax credit, but only once. So a family that bought a $40,000 car because it was sold to them as if it were a $32,500 car, still has the larger payments for the next few years of a $40,000 car. For people at that level, it can be a stretch.
So it's not really the $7500 lopped off the top that these manufacturers make it out to be.�
Mar 10, 2011
bolosky True enough. However, the President's budget proposal includes switching it from a tax credit to an instant time-of-purchase rebate so it would really become an effective lowering of the price. Now, whether this makes it through congress is a different matter.�
Mar 10, 2011
ckessel True. I was going to argue that typically if you're at the edge of what a bank would loan you, then you're probably pretty far beyond what you should be borrowing anyway. But you're right, on the low end EV's, that $7500 is a very significant portion of the price and could come into play.
The thing I don't like about it as a credit is that it's something that's tilted against lower incomes (yea, what else is new in our society). If someone doesn't play $7500 in federal taxes, they can't get the full value of the credit. The point of the credit, in theory, is that the government believes it's in the national interest to promote EV purchases. Not that it's extra good for rich or poor, but that's good in general, and so I think the credit should instead be a rebate that's income agnostic. Bolosky noted that's already being attempted in congress, but, well, let's face it, every republican is going to rail against it (again, what else is new).�
Mar 10, 2011
Lloyd Does this apply to used purchases as well, or did you have to buy it new from the factory?�
Mar 10, 2011
vfx I don't know the exact details Lloyd.
Anyone else?�
Mar 10, 2011
richkae A long time ago Tesla offered current Roadster owners an opportunity to put down the $40k for the signature, and if you did you would get $10k off whatever the final price was.
I think it was at least a year ago, and the offer has been over for a long time.
I didn't do it, and since hindsight is 20/20 I am kicking myself now.�
Mar 10, 2011
dsm363 I'm pretty sure this is only for new purchases.
Have you called Tesla? I put down the deposit for the Model S in 2009 and didn't decided to get the Roadster until Oct. 2010 and they were still doing that program.�
Mar 11, 2011
cinergi A Tesla rep told me that program ended at the end of last year -- but it never hurts to call (who knows what programs are running these days).�
Không có nhận xét nào:
Đăng nhận xét