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Comment by BruceIV | Hacker News Reader

What got me is a charge rate of "150 miles of drive time in an hour" - so it takes an hour to charge for every 2.5 hours of driving?

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Would be neat if the battery itself was something that was like a module. You could drive up to the driving station and some kind of robotic arm would just hook up - swap out your battery module and replace it with a charged version. In essence companies owning the charging stations would own a pool of batteries that they would charge and swap in and out of drivers cars.

The Tesla battery contains over 6800 3100mA 3.7V Panasonic 18650 Li-ion battery cells. It costs $40,000 to replace. This battery has a life expectancy of 500 charge cycles. That means the battery cost per 240 mile charge is $80, and the company would have to charge that to recover just their battery costs. Add another $20 to handle tax, labor and the cost of maintaining the equipment and the recharging, so $100 per swap, assuming this is run as a non-profit endeavor. Do you feel there is a large market for people willing to pay $100 for every 240 miles they travel? Such a network of replacement stations assumes that the market will pay these costs.

a) http://green.autoblog.com/2012/11/30/tesla-adds-replacement-... suggests that the battery replacement costs are much lower ( < 12000 in the worst case for the 85-kWh pack and as low as 8000 for the 40kwh pack). I dont know if this price assumes that you will be turning your old batter in - otherwise I would imagine you would be able to recoup some money for that via selling it to recyclers.

b) Also http://batteryuniversity.com/learn/article/how_to_prolong_li... suggests that the 500 charge cycle number is only valid if every cycle depletes the charge to 0. Assuming that each cycle discharges to 25% - the number of cycles goes upto 2000 - 2500.

Assuming a price of 10000 (Using a medium capacity battery as well as assuming whole sale prices) and a depth of discharge of 25% per cycle and hence assuming battery life of 2250 cyles - you get the battery cost per charge to be 12000 / 2500 = 4.8 . Assuming a 10% tax rate thats about 5.28 dollars per cycle. This number does not seem bad at all.

Tesla offers, for a $12,000 fee at time of purchase, a replacement policy that will replace the battery AFTER 8 years of use, and only after 8 years of use. This brings the price of the 240 mile range model to $91,900, plus tax and licensing. It is not a warranty that replaces the battery if it fails. It offers no coverage before 8 years, and at 8 years one may replace at any time.

Tesla also has cited a price of $40,000 for battery replacement for drivers whose batteries have failed due to not being recharged properly or other reasons. This price is consistent with the lowest wholesale costs of these battery cells on the global market, with no markup for their added value of the battery enclosure, cooling, heating, monitoring, and recharging hardware, thus it is a fair deal and good value as Tesla is clearly not taking any profit at this battery price point.

Tesla does not sell the 85kWh batteries (the ones needed to have a 170-240 mile range) for $12,000. If you hand them $12,000, they will not hand you a battery pack. If Tesla could sell these batteries at this price, they could sell a tremendous number to Nissan, GM, Boeing and others. They could even charge $20,000 and would still have plenty of buyers as it is far below the lowest wholesale cost of the 6800 3100mA 3.7V Panasonic 18650 Li-ion battery cells it contains. Or even better, customers could buy the 6800 new 18650 cells in the pack from Tesla for the $12,000, remove them from the battery pack, and become a wholesale dealer of the cells, able to undercut Panasonic's lowest wholesale price by up to 75%. One could make millions selling new battery cells to laptop battery pack manufacturers that use these cells. It is a sure fire guaranteed profit if, as you say, Tesla is selling battery packs containing 6800 brand new 3100mA 3.7V Panasonic 18650 Li-ion battery cells for only $12,000. It is the bargain of a lifetime. No VC would pass on funding such a venture, it is a guaranteed profit.

The claim that Tesla is selling these battery packs for $12,000 is false. Tesla is not selling these batteries for that price. They will sell these batteries for $40,000 though, as Tesla's Vice President J. Joost de Vries has stated that that is the price for those who need a replacement.

Tesla does offer to deliver a replacement battery in no less than eight years from purchase date for $12000 (February 2021 if you buy today), to the original owner, provided this fee was paid for when the car is purchased, and provided Tesla is still in business. This is not the same as selling batteries for $12000.

Thanks for providing this information - I stand corrected.

Agreed. This seems a much better business model. You avoid the cost/liability of owning and replacing the batteries too. On the downside, you're back to paying out money to an energy supplier like we do today for gas.

http://www.betterplace.com/

Buy the car, rent the battery, turn in a spent one for a charged one in a few minutes.

These times are only assuming you stop at a 440V Supercharger, of which there are eight total nationally, and only on three road routes, six stations on two California routes, and two stations on a single route between DC and Boston. The 440V high amperage charge also lessens the life of the battery - Lithium Ion cells don't like high amperage or temperatures. Fortunately battery replacements are only $40,000.

A 240V 24A charger which is much more common, and which is not paid for by Tesla so has its own terms, can recharge 18 miles of range per hour of charge, so 13 hours are needed for a full recharge.

A 240V 40A charger can recharge 31 miles of range per hour of charge, so 8 hours are needed for a full recharge.

Tesla also notably recommended that people drive low speeds on long trips to increase the chances they will see ranges of 240 miles as opposed to the 170 or so that seems to be under more typical driving conditions.

When one is off of the Tesla routes on the west and east coast, and driving a steady 60mph without climate control, one can travel 240 miles per 12 hour period if they have access to the higher capacity 240V/40A charger exactly every 240 miles (20 mph average speed), or 240 miles per 17 hours with the 240V/20A station (14.1 mph average speed). This is assuming there is no cold weather. If there is cold weather or faster driving, that reduces to a 170 mile range per 12 or 17 hour period (10-14mph average).

Tesla plans to address this with a nationwide network of Supercharger stations which will reduce the full recharge time dramatically, at the cost of shorter battery life.

Tesla claims that all energy for the network, which requires the ability to deliver to 4 cars simultaneously in 1 hour about 100kWh total of power per 85kWh capacity charge, will run exclusively on a small 30 kW max rated capacity installation of solar powered panels at each 4 car charge station and that customers will not only "Drive for Free. Forever. On Sunlight.”, but stations will produce a surplus of energy that will be sold at a profit.

source for recharge times: http://www.teslamotors.com/charging#/outlet

source for solar powered car claims: http://www.visualnews.com/2012/09/26/tesla-electric-cars-dri...

What I never get is why doesn't anyone ever propose battery exchanges instead of charging stations. It would make a lot more sense to pull in and exchange your dead battery for a charged one (just like buying propane).

> What I never get is why doesn't anyone ever propose battery exchanges instead of charging stations.

It is being discussed in general, not about the Tesla but in the abstract. The Tesla's battery weighs 990 pounds, so it would be a serious undertaking to swap it or a battery like it.

I keep thinking exactly the same.

Possibly it is because you can do a lot more damage to a battery by mistreating it than you can to a bottle of propane?

You are wrong about battery replacements - they are $8,000 to $12,000 dollars depending on capacity, and batteries are covered by an 8 year warranty.

You are not correct.

The 6800 3100mA 3.7V Panasonic 18650 Li-ion battery cells used in the Tesla S battery pack have an expected recharge life of 500 charges, which is just over a year if you commute and recharge daily, and is less if you do high amperage recharging such as by using supercharger stations. Most current users are commuting on occasion with their Tesla and do not recharge daily, but 2-3 times a week, so the battery, by avoiding Superchargers, will likely last 4-5 years before the range is reduced to the point that it becomes a problem. This leaves the driver with a car that has a significantly reduced driving range for years 5 through 8 of ownership while waiting for the replacement policy to kick in. (Also worth noting is that for Li Ion battery technology, battery life is damaged by high operating temperature, Arizona drivers in particular should expect shorter life, Alaskan drivers can expect longer life.)

Tesla does offer a $40,000 at-cost replacement for drivers whose batteries have bricked due to not being recharged properly, left in parking lots, or are more than a few years old. This is consistent with the lowest wholesale costs of these battery cells on the global market, with no markup for their added value of the battery enclosure, cooling, heating, monitoring, and recharging hardware, thus it is a fair deal and good value as Tesla is clearly not taking any profit at this battery price point.

Yes, that is one of the EV issues. Primarily why, I assume, hybrids and electric cars like the Volt have seen more widespread use because they have a gasoline fallback. The popular counter argument is that the vast majority of daily driving amounts to less than 40 miles.

Fair enough - but you'd need a charging station at your destination to make the OP's argument work, because if you charge your car at home every night like your phone, you're on the hook for the electricity (which probably costs more per mile than gasoline - I don't know, but I know it's cheaper to heat with diesel then electricity, so I assume auto fuel is similar)

Very incorrect. A short back of the napkin calculation:

286mi/85kwh / .12 (dollar per kilowatt hour) = 28 miles per dollar or .03 per mile.

Gasoline on the other hand is:

30 mpg / 3.50 (dollar per gallon) = 8.5 miles per dollar or .11 per mile

Electricity comes out far better. Cars are much less efficient than heaters at capturing the stored energy from it's fuel. With a heater you have the benefit of insulation and none of the losses associated with moving a hunk of metal through air.

In NYC, I pay a total of 41 cents per kilowatt hour (including supply charges, delivery charges, fees and taxes) for my electricity. (Source: my latest electric bill. Total of $56.36 for 137 kWh.)

Using that cost in your calculation would yield 8.2 miles per dollar, or .12 dollars per mile. -

In southern Ontario, I pay 6.5 cents/kWh (off-peak, say the "charge at night" scenario I mentioned as a hypothetical.) and $4.50/gallon for gas. (the exchange rate between Canadian and American dollars is even right now). -- That's 0.15 $/mile for gas and 0.02 $/mile for electric.

... huh, so I'd be saving nearly about $850 $/yr with an electric car, even though I only drive about 6500 mi/yr (though half of that is the cross country trip to visit my folks). That said, my car only cost $5500, so it would take longer than the life of the car to pay off the difference to a Tesla.

What's your gasoline cost like though? Similarly expensive I'd wager? These number have to be compared together to be worth a damn. Though yes the numbers make more sense in areas with lower per KWh costs. Cars barely make sense in NYC to begin with it seems though, who's that much of a masochist.

A gallon of gas costs around $4.00 here right now, not much different from the $3.50 assumption in the original calculation.

Lots of people in NYC have cars. NYC isn't just Manhattan, and much of the area in the outer boroughs is more suburban than urban and not accessible via subway.

Large areas like NYC are also going to be the first to have the super charger networks rolled out to them and also more likely to have charging stations available in car parks. But yes home charging doesn't make sense everywhere yet.

Thanks.

> which probably costs more per mile than gasoline

Though electric cars are much more efficient [1]

[1] https://en.wikipedia.org/wiki/Electric_car#Energy_efficiency

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