Is it just bulk that makes the batteries non replaceable? Putting in charged ones are after all the simplest way to speed up charging if the replacement is relatively simple, and a well proven solution for other battery powered devices.
This sounds like a program that was designed to fail so they could say that they tried. I don't see a ~400mi charge from zero ever happening in the sub-10 minute range. A swap is the only way to do that without a major technological breakthrough. Swaps have their own logistical problems, but swapping battery packs is the best solution for cars, phones and anything that needs a battery that can be easily swapped.
I think it's also too new in battery tech for this to happen. Batteries need to become more like a commodity everyone thinks is interchangeable before this becomes truly viable.
If I own my car (and battery) I probably take pretty good care of it. Who is to say I'm swapping with a battery that has been poorly cared for? This anxiety alone (justified or not) means a lot of owners won't currently do this. Tesla "tried" to solve this - but if I have to plan ahead for when I want to do a swap it's again a hugely useless service. The entire reason battery swaps would exist, is to make charging an afterthought non-issue.
Basically I can see once electric cars get to be the majority and battery tech drives prices down this happening more - probably starts out more like a battery service/extended warranty plan where you pay a monthly fee for a certain guaranteed performance. Then this company will develop the repair/service infrastructure to be positioned to take advantage of any standardized battery swap tech for their customers.
It's fun to think about the new markets here, but right now battery packs are more like pets than cattle.
> This sounds like a program that was designed to fail so they could say that they tried
You're getting downvotes, but I think that's accurate. Tesla built a battery swap station in order to qualify for extra ZEV credits worth millions of dollars that California was offering as an incentive to develop an EV that could be charged as fast as gasoline cars. They met the bare minimum requirements to qualify for those credits, and the station was likely never used by anyone other than a few reporters, then quickly closed after the credits were earned.
The station was "opened" in a way that seems to me designed to ensure nobody would use it: you had to be invited to take your car there, you had to call several days ahead of the time you wanted to do so to make a reservation, you had to pay $80 for the privilege, and you might not get your own battery back. The swap station was located across the street from a Supercharger where you could simply pull in without a reservation and quick charge your car for free.
> They had a swappable demonstration a couple years ago and the model s supports it.
This was basically a ploy to get government dollars. The tax rebate per vehicle was partially determined by capabilities the car had theoretically, even if they weren't deployed in a useful manner.
As in Tesla didn't want to store and insure tons of batteries, especially because their current limiting production factor is batteries. Every battery that can be swapped is one that isn't being used in a car.
With batteries the size Tesla has, you really want to take a break after several hours of driving anyway. So the supercharger time adds only little delay to your travel.
For reference, gas contains about 33kWh of energy per gallon, and if we assume you pump 20 gallons in 5 minutes when you fill up your car you have an effective energy transfer rate of about 8 MW at your gas pump. Even if we give an electric vehicle a 3x efficiency ratio, we still need about 2.5 MW to be equivalent to the old petroleum infrastructure.
The comparison is not quite that easy. The old petroleum infrastructure is more centralized.
You can get electricity almost anywhere, adding a charging station to parking places or garages is far easier and safer than hypothetically laying gasoline pipelines everywhere. So there are more opportunities for partial charging when the car is idle.
And in addition: the efficiency of a petrol-engine is much lower than an electric engine. So you perhaps only take in half of the fuel, if it gets you just as far you have what you need, isn't it?
What do you mean "laying gasoline pipelines everywhere"? Gas stations do not connect to any utilities apart from the regular electricity, water, and natural gas, all of which require a physical connection to centralized infrastructure.
A hypothetical scenario where we have the gasoline equivalent of charging columns at parking places or garages and distribute gasoline to them like we do with electricity.
That's only doing the math on the instantaneous flow rate down the nozzle/plug. Pulling into the station, waiting in line, hitting the rest room and paying the bill need to be included too to get a relative penalty.
Also: if that 33kWh/gallon number is a heat of combustion (I'm too lazy to convert to real units or look it up myself) the efficiency gains of an electric motor vs. an internal combustion engine is significantly higher than 3x, I believe.
> Pulling into the station, waiting in line, hitting the rest room and paying the bill need to be included too to get a relative penalty.
This is not the average experience for a US driver. Very few gas stations ever have all their pumps utilized, even during rush hour. I haven't gone into a gas station in years, or waited on paying the bill - everything is automated at the pump.
I would put the "convenience store" aspects at par - you either want some snacks or need to use to rest room or do not - the fuel type doesn't change that.
Payment again I'd put at par - swipe a credit card at the "pump".
Maybe add a minute for "average wait for a free pump" to the gas station model, but I'd argue that problem would be even worse (or at least par) with electric charging.
The only real win I can see is that you could do other things away from the vehicle while it charges (attended vs. unattended fueling) which lets you parallelize some activities above. But that only becomes useful once the refueling times become within the average potty/snack break at a gas station - and we're no where near there yet.
You're overcomplicating. Take a stopwatch. Start it at the point where you exit your normal driving routine to "get gas". Stop it when you resume. Take that time, subtract the time spent actually pumping fuel (which even in your convenient utopia is still going to be less than 1/3 of the total), and add the time spent to equivalently charge the vehicle.
Then divide the two totals to get a relative penalty to an electric car. If you're doing the analysis any other way, you're almost certainly doing it wrong.
Yes, on average this would slightly affect the result, but I'd be shocked if a non-negligible number of trips to the gas station for most car drivers involved entering the convenience store, particularly to "hit the restroom". Most people spend their lives driving back and forth between two places that have clean and (certainly relatively to a gas station) pleasant restrooms: the only people stopping at a gas station are on long road trips; and while I do a ton of these, I'm still usually not doing it a gas station: most people are probably stopping at whatever their favorite fast food restaurant is and going to the bathroom there, which satisfies their food craving at better cost efficiency than the overpriced even lower quality junk at the gas station and, at least today, doesn't parallelize that well with either filling their gas tank or charging their battery. (And except during small windows of time when only desperate people are getting gas, there generally are not lines at gas stations.)
> I'd be shocked if a non-negligible number of trips to the gas station for most car drivers involved entering the convenience store, particularly to "hit the restroom".
More like 36 kWh. Average mpg of new cars is 25.5 mpg (.71 mi/kWh) while Teslas get 3.2-3.8 mi/kWh so the efficiency ratio is closer to 5x. With 4 gallons/minute, that's 7.2 kWh per gallon/1.73 MW. In the US pumps reach up to 10 gallons/minute so 4.3 MW and 17.3 MW for truck-filling pumps. Not all pumps hit 10 gallons/minute though.
2 or 3 MW would charging power would require a really specialized battery and will probably never be worth it. The real advantage of an electric car is letting it charge overnight and adding some extra time over long journeys isn't a big inconvenience- its less time than unexpected traffic would take up. Plus the time is overall made up for by never having to fill up if you come home to charge overnight once a week. Same thing applies to trucks. An hour-long fill up once a week gets replaced by nightly charging.
> Average mpg of new cars is 25.5 mpg (.71 mi/kWh)...
This is not a reasonable way of doing this math because it loads the numbers with "people who want a large and heavy car can't or wouldn't buy an electric, pulling down the average miles per gallon for gasoline powered vehicles"; to do this comparison fairly requires looking at the energy conversion efficiency of the engine, tank/battery, and transmission in isolation of the rest of the car body. Another way to put this: if you manage to buy an electric Hummer, you are going to be spending an insane amount of time charging it, because it would use as much more electricity as it uses more gas ;P. If you really need to estimate this using miles per gallon, you need to look at a gasoline-powered car which looks like a Tesla (being about the same size and contour), not the average new car purchased by a consumer. (FWIW, a quick eyeball of this is looking like 40 mpg.)
The biggest factor towards overall mpg is actually engine size, not aerodynamics. Gasoline engines have to run at their ideal power to stay efficient, induction motors do not (for the most part). You're eyeballing the wrong places if you're getting 40 mpg. Compare a BMW 5, 6 or 7 series- 19/27, 21/30, and 21/29 mpg. 25 is, if anything, optimistic. The only cars that get 40 mpg are subcompacts and some compact cars. 25.5 is a good balance between all of the small cars and the SUVs/pickups, because the Model S is between them in size and weight. In fact it tends towards the upper end- although it is very aerodynamic, it is a quite large and quite heavy car.
When the model 3 comes out, we'll be able to make better comparisons to high mpg ICEs like the fit, fiesta and civic.
If we're talking 'next-gen' tech vs 'next-gen' tech, let's be a little fairer, newer cars are using the Atkinson not the Otto[1]. Throw in the fact that we're no longer tied to a camshaft for timing[2], cylinders can be shutdown at will (e.g. you're in bumper-to-bumper on the 405 or 101, your Benz-AMG or Stage 3 Mustang doesn't really need all 8 cylinders firing) and the fact that most manufacturers have at least one car with the option to reclaim that heat (i.e. even Ford Mustangs, notorious for being gas guzzling pony cars, have a turbo-hybrid configuration option) and things for the ICE look a little less bleak.
I'm all for pure-electric cars but we're still a long way from Joe the miner in Kentucky from being able to drop $1800 on a 2000 Toyota Tundra and having it be able to get him reliably from the jobsite and back. That's not even factoring in the whole capacity-decrease-with-use (and even non-use-- deterioration occurs simply by just storing cells at full capacity for long duration -- of lithium.
Even with the best, most conservative profiles on a battery-module controller for anything lithium based, good luck getting > %50 of cell capacity 5 years down the road of a daily driver [edit: 7]. Anode deterioration (at least, last I seriously researched it for projects requiring portable units for driving larger loads than an average car was ~1.5 years ago) was still a problem even in the lab.[3]
My sister abuses her 2004 Civic coupe to the point where I think she's still running a stock air filter and runs 30-35k between oil changes[4]. This was a run of the mill car she's had since god-knows-how-long and she's still getting 22mpg city [5] ~26 highway on an automatic transmission.
tl;dr -- In terms of total costs :
- capital (purchase) / delivery fee
- operational ($ of petrol for ICE per unit travelled/$ of energy from your power supplier per kw/h), insurance
- maintenance (tire wear, brakes, battery module(s) replacement(s)) over, eh, 5 years from out-of-the-showroom-into-your-garage, I'd be surprised if you saw the electric dollar-for-mile-traveled outperform it's ICE counterpart.[6] I'm far from the forefront of Li, but I do have a few friends in that field (both in academia and
in industry) -- even the most optimistic don't see pure-electrics reaching a TCO parity point of an ICE for the consumer in less than 10 years.
[2] https://www.youtube.com/watch?v=FJXgKY2O4po FreeValve as explained by that really enthusiastic "Engineering Explained" 24 year old automotive engineer, dumbed down to the point where even I can grok it.
[3] Rumor had it, DARPA was using some crazy proprietary stuff that managed to completely nullify dentrification, but if they've managed to accomplish that anodic behavior, there's no way it's going to be released for public usage -- rather, it'll remain hush-hush minus 50 PhD's in metallurgy, and Lockheed drones all of a sudden posting performance numbers +30% from the last revision.
[4] She's not using those long-lasting synthetics that have additives to SeaFoam (yeah, I'm using it as a verb) out carbon build-up on the cylinders and what not, in case you're wondering. Just cheapo 5w/30.
[5] That, albeit was with me driving in 'conservative' mode rather than "hmm let's see the 0-160 on this McLaren".
[6] And I'm 100% sure if you bought a 3 year old variant of an ICE vs a pure-electric, it's no contest -- vvanders↗
Not sure where your getting your 50% degradation numbers from, I have 2 years of daily use, 43k miles and only ~2% degradation.
(old-ish study, apologies, but was cutting edge circa 2010, but still stands re: LiFePO2 which I'm betting your '14 production car is using) -> http://ecec.mne.psu.edu/pubs/2010-zhang-jps.pdf Page 2, Column 2, Figure 1, Top chart. 300 deep-cycles @ ~92%, 600 @ 74%.
If you're the average SV guy who 'daily drives' his Tesla 20 miles from Oakland to his lofted startup where there's 220 to full-charge before you go home, you'll get 2%. Johnny in Kentucky working the coal miles doesn't have that luxury and will certainly enter into 'deep charge' consumption. (600 cycles -> ~75%, with 2nd deriv of batt life w/r/t cycle being negative, i.e., progressively decreasing losses).
Again, not in the field professionally, but these opinions are consistent with my friends who are working at the forefront (albeit, a statistically small sample space, I openly concede !)
If by daily driver you mean weekly 300mi weekly roundtrip that usually ends around 5-10% and ~30 miles a day otherwise then sure.
My numbers line up with what most Tesla owner experiences. If your friends are at the forefront of the profession then I'd be a bit worried about whoever they're working for.
Tesloop, the transport company that'll shuttle you between LA and Las Vegas via Model S, has only seen 6% degradation over 180k miles on their vehicle; this is with ignoring Tesla's advice not to charge to 100% every time at Superchargers.
> good luck getting > %50 of cell capacity 5 years down the road of a daily driver
The data doesn't bear this out. Users have been seeing 5%-10% degradation over the first few years, after which point it levels out.
After 10 years, I expect to have >80% of capacity still usable.
The enemy of lithium ion is high state of charge, as you said, and high temperature. Tesla gives you control over how much you charge the battery, so you can easily avoid a high state of charge.
The big deal is temperature. Your laptop, cell, power drill, etc. do not have temperature control. The battery overheats frequently and capacity suffers, until the battery is dead. Tesla has an active liquid temperature control system in the battery pack. It cools the battery when it heats up and heats it up when the pack is cold, keeping the temperature under control. This preserves capacity long-term.
> After 10 years, I expect to have >80% of capacity still usable.
It's pointless to talk about capacity at year X without accounting for range, your driving habits and miles/year.
Capacity loss is not a dependent variable of just time, but most importantly of the number of recharge cycles. This is why Nissan Leaves (especially 1st gen ones) have experienced huge capacity losses when used as daily drivers (think 30% loss @ 50,000 miles). Depending on how long it takes you to drive 50,000 miles, the time frame can be as short as 3 years.
Of course a Tesla needs fewer charges to go 50,000 miles, but that obviously comes with a huge price premium over the 'economy EV' like a Leaf or a Kia Soul or what have you.
> but most importantly of the number of recharge cycles.
That was the point I was alluding to. You're mistaken in thinking that this is the most important factor. It isn't. The most important factors are extreme states of charge and temperature. If you account for those and control those, you can easily go a million miles on the battery pack without any kind of major issues. The rest of the car will fall apart before the battery pack gives out or suffers major degradation.
On the flip-side I don't have a gas station in my garage or my work's parking garage, but either can be trivially outfitted with a 220v plug. Ideally, one's recharge strategy shouldn't be like filling up a gas car. You should be plugging your car in for overnight charging and only using these types of stations in a pinch. With gas cars, I have to use these stations. They're literally my only choice. I couldn't build a gas station in my garage even with vasts amount of money due to regulatory, safety, and environmental concerns.
Its also more reasonable to tap into overnight power as to not stress the daytime powergrid.
>gas contains about 33kWh of energy per gallon
ICE are about 20-30% efficient. So 70% of that 33kwh is lost to heat and other inefficiences. Electric cars are about 70-80% efficient, so you actually need only 1/3rd the energy capacity in this kind of calculation to match ICE/gas.
The thing to keep in mind when thinking about EVs is that while they may be slower to fill up at stations where you have to stand there like the Tesla super charger stations, this is a small minority of the charging most EV owners do.
Most of the time my LEAF gets charged at home in my garage. We only use public chargers a handful of times per year. When we do, it's stations in parking garages or public parking lots. Which means we plug it in and walk away. We don't have to stand there with it while it charges. If it takes a couple hours that's fine.
People focus on how fast they can recharge their EVs while they are standing there waiting for them because they are used to having to go somewhere to refuel their gasoline powered car. One of the great things about owning an EV is you recharge at home.
Except that Tesla is now charging $0.40/minute of leaving the car plugged in after a full charge is reached. They do this precisely to prevent people from "abandoning" their car while others wait in line.
That's because Tesla's supercharger system is designed to work more like the refueling system people are familiar with and comfortable with; pull up, plug in, wait for it to finish and then drive away.
One of the beauties of EVs is not having to use that style of system. The superchargers are nice but most of the time you won't use one unless you're regularly driving over 200 miles a day.
I totally agree that almost all Tesla charging doesn't happen at superchargers. But where did you get the idea that anyone intended that owners should stay with their cars while charging? I've only seen that when nearby services are closed. Tesla has always advertised services nearby superchargers, and now that's visible on the in-car display.
If I'm eating dinner nearby, it's easy to run out and move my car, or, there's a valet to do it at overly-popular superchargers. The Tesla phone app gives plenty of warning.
While all of this is true, charging time is an issue because it limits range. A gasoline powered car is just a 5-minute detour away from doubling its range, which compares terribly with the sort of vehicle you're going to want to walk away from to do something else while the charging does its thing.
Apparently people leaving Teslas longer than necessary in the supercharger spots is already an issue [1] that they are trying to rectify by charging for overstays.
It's true, if you are the type of person who often drives >200 miles a day EVs today are not as convenient as gas cars for those trips.
But that is a very small percentage of people. If only those people bought gasoline cars in 2017 they would sell fewer than the number of EV cars sold in 2016.
Assuming he's not being sarcastic, it could be power aimed at semi trucks. That would probably be sub-megawatt for regular charging, and 1-2 for supercharging. It's gonna be a lot more important to have a well-developed charging network for trucks since they are working vehicles: nobody is gonna buy a truck and then sit around and wait for it to become profitable to drive. Maybe we'll see some extra-large charging spaces opening up soon...
It would probably be easiest to swap the cargo onto a charged tractor. Since there is no driver, you just have an automated station that swaps the tractors and the cargo goes on its way. Swapping a giant long haul battery would be very cumbersome.
I agree though that swapping and slower charging would make more sense than trying to charge at some multimegawatt level to reduce the cargo transit time.
Not really. Unless you are driving team you still only get 10-11 hours of driving a day. (iirc. I know the regulations have changed a LOT since I grew up in a truck in the early 00's)
There is plenty of time to recharge a truck over night at a truck stop. The issue is gonna be infrastructure at the truck stops. I am gonna guess at 150-300 spaces at most truck stops. If the majority of trucks go electric then I am not sure the electric grid's connection to the truck stop is gonna be able to support that.
Anybody know the math on how much electricity would be needed to take an 80,000lb truck 700 miles? (700 miles would be on the very upper end of the scale but you want that kind of range to accommodate for climbing hills with a full load.) And after that the math for charging say 100-200 of them? (I doubt the truck stops will all be charging at once)
Trucks stay stopped a lot of time for loading and unloading. Most could easily have an 1 hour charging without any issues.
Superfast chargers would be great for self-driving trucks making long distance trips. But then, train corridors probably beat those on every way.
For vehicles where somebody is inside, I don't really see the point of 5 minutes charging. People need to rest and eat, and nobody does that in 5 minutes. Plentiful slower chargers would be a much better selling proposition.
I did some analysis and think batteries will be somewhere 1-1.5 MWh for tractor trailers. 3 MW would still take 20-30 minutes to charge that. The middle ground isn't very useful as delays on deliveries lose a lot of money. Even an hour long delay cuts into profits. Unless you can charge at .5-1 MW, its not any more useful than just charging overnight.
Even 4-5 minutes is still an eternity if you're in a queue behind 10 cars during the holiday rush, and have to 'fill up' twice to get to your destination. What would be a 20 minute wait for gas becomes an hour, for something that doesn't even give you the same range.
For long distance travel, one would install some more superchargers than fuel pumps. In day to day driving recharging should not be an issue at all, as it should happen over night anyway, you start with a filled up car every morning.
600 KW is some chunky wattage. It's unlikely you can charge very many cars at the same time without having a power station next door. Delivering, for example, 10 megawatts to handle 15 cars simultaneously, requires some very heavy electrical and safety engineering, which would be very costly. You could run pylons along the highway, but then you'll need an high-wattage electricity substation next to each charging forecourt to bring the voltage down.
A gas fuel tank under a service station, however, is cheap, and is limited only by the size of the forecourt in how many cars it can simultaneously service. And we still have the problem of charging time. You'd probably talking a forecourt capable of charging 100-200 cars simultaneously during peak times. That's 60-120 megawatts on Musk's fast charge. That's enormous. It's an entire small power station.
For any long distance, my sense is that electric cars are still at a heavy disadvantage to the ICE for the foreseeable future, even assuming Musk's optimistic charging cycle projections.
Let's face it, gasoline still has some miraculous energy storage density / transportability advantages.
It's unlikely that you'll hit those wait times due to other cars at the same supercharger, I think. Not all trips require a visit to a supercharger and unlike ICE, owners of electrical recharge daily at their homes.
It could happen for some popular routes, but it will be a minor nuisance and easily fixed with more supercharging stations on the routes that are more congested.
The real problem with shared ports is that cars still occupy stations when they’re done charging, and they are not even required to “plug in” while using the convenient parking spots.
You need a way to force a car to start charging while parked in special spots, and force it to leave when done (the Tesla actually could move itself out of the way automatically, if only there weren’t a charging cable attached).
It would be a nice enhancement for drivers to have their cars move to non-charging spots after they finish charging. However, Tesla introduced fees just recently: https://www.tesla.com/support/supercharger-idle-fee. Also, after Dec 31, supercharging won't be unlimited for newly bought Teslas.
I wonder what the Tesla charging contacts are rated for. Assuming they keep the straight-to-battery model, 350kW is around 1000A. I think Tesla chose the best available contact for its size (I forget the brand name), but 1000A is a lot for that size contact. They may have to devise a way to actively cool it.
I doubt that they want to start supercharging at higher voltage. A DC-DC converter at that scale will be fairly large. I suppose they could add some contactors internal to the battery pack to change the cell wiring to double the voltage and halve the current for charging purposes.
In the above case, they used liquid cooling to make the charging cable diameter smaller, but perhaps the technology can be used to make the regular Supercharger cable capable of handling more power.
Cooling the cable might be easier: you can make a hollow braided copper tube, insulate and seal around it, and run liquid through it. But you can't run liquid through the contacts unless the car has plumbing for it, and I doubt it does.
Whoa, lets take off our socks and count there, mr ad-hominem
There is ~56 weeks in a year, so with that kind of use you get 10 years worth of deep cycles (600)
The light ones were shown already to have basically no impact.
Meanwhile, in real world people have harsher climates that will screw with the batteries even further - where I live summer goes to 35-40C and winter can go as low as -20-25C
Also, current "normal" electrical grid is not capable of charging dozens of cars at the same time, even with slow charging
Any medium business can have 50 or more cars parked and I higly doubt they will go to the trouble of upgrading their power connection by an order of magnitude -> which means no one working there will even consider an electric car
Sure, I'd love to have an electric car to do my daily commute (total of 10 miles), but since those are so riddiculously expensive, unsuitable for my climate and depreciate riddiculously quick it's kind of a moot point
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[ 3.5 ms ] story [ 179 ms ] threadYou mean HN?
They're focusing instead on fast charging.
If I own my car (and battery) I probably take pretty good care of it. Who is to say I'm swapping with a battery that has been poorly cared for? This anxiety alone (justified or not) means a lot of owners won't currently do this. Tesla "tried" to solve this - but if I have to plan ahead for when I want to do a swap it's again a hugely useless service. The entire reason battery swaps would exist, is to make charging an afterthought non-issue.
Basically I can see once electric cars get to be the majority and battery tech drives prices down this happening more - probably starts out more like a battery service/extended warranty plan where you pay a monthly fee for a certain guaranteed performance. Then this company will develop the repair/service infrastructure to be positioned to take advantage of any standardized battery swap tech for their customers.
It's fun to think about the new markets here, but right now battery packs are more like pets than cattle.
You're getting downvotes, but I think that's accurate. Tesla built a battery swap station in order to qualify for extra ZEV credits worth millions of dollars that California was offering as an incentive to develop an EV that could be charged as fast as gasoline cars. They met the bare minimum requirements to qualify for those credits, and the station was likely never used by anyone other than a few reporters, then quickly closed after the credits were earned.
The station was "opened" in a way that seems to me designed to ensure nobody would use it: you had to be invited to take your car there, you had to call several days ahead of the time you wanted to do so to make a reservation, you had to pay $80 for the privilege, and you might not get your own battery back. The swap station was located across the street from a Supercharger where you could simply pull in without a reservation and quick charge your car for free.
http://www.businessinsider.com/teslas-battery-swapping-plan-...
Main issue is a social issue - people like to have ownership of their own battery pack.
This was basically a ploy to get government dollars. The tax rebate per vehicle was partially determined by capabilities the car had theoretically, even if they weren't deployed in a useful manner.
http://www.csmonitor.com/Business/In-Gear/2015/0312/Tesla-ba...
http://www.latimes.com/business/autos/la-fi-hy-tesla-battery...
> Main issue is a social issue - people like to have ownership of their own battery pack.
What's the evidence for this? People have no trouble with propane tanks they don't own for gas grills.
You can get electricity almost anywhere, adding a charging station to parking places or garages is far easier and safer than hypothetically laying gasoline pipelines everywhere. So there are more opportunities for partial charging when the car is idle.
Ironically, that's safer exactly because electricity won't give you those MW-scale powers.
Also: if that 33kWh/gallon number is a heat of combustion (I'm too lazy to convert to real units or look it up myself) the efficiency gains of an electric motor vs. an internal combustion engine is significantly higher than 3x, I believe.
This is not the average experience for a US driver. Very few gas stations ever have all their pumps utilized, even during rush hour. I haven't gone into a gas station in years, or waited on paying the bill - everything is automated at the pump.
I would put the "convenience store" aspects at par - you either want some snacks or need to use to rest room or do not - the fuel type doesn't change that.
Payment again I'd put at par - swipe a credit card at the "pump".
Maybe add a minute for "average wait for a free pump" to the gas station model, but I'd argue that problem would be even worse (or at least par) with electric charging.
The only real win I can see is that you could do other things away from the vehicle while it charges (attended vs. unattended fueling) which lets you parallelize some activities above. But that only becomes useful once the refueling times become within the average potty/snack break at a gas station - and we're no where near there yet.
The ones operated by grocery stores (giving gas discounts on $X of groceries bought) are always full during rush hour.
Then divide the two totals to get a relative penalty to an electric car. If you're doing the analysis any other way, you're almost certainly doing it wrong.
I'm going to contend you're exactly wrong, actually -- literally backwards.
For an electric car, routine fillups don't actually exist. You charge it at home and it's always "full" for commute trips.
Electric service station visits happen on long trips. Notably, so do bladder full exceptions and blood sugar shortfalls.
2 or 3 MW would charging power would require a really specialized battery and will probably never be worth it. The real advantage of an electric car is letting it charge overnight and adding some extra time over long journeys isn't a big inconvenience- its less time than unexpected traffic would take up. Plus the time is overall made up for by never having to fill up if you come home to charge overnight once a week. Same thing applies to trucks. An hour-long fill up once a week gets replaced by nightly charging.
This is not a reasonable way of doing this math because it loads the numbers with "people who want a large and heavy car can't or wouldn't buy an electric, pulling down the average miles per gallon for gasoline powered vehicles"; to do this comparison fairly requires looking at the energy conversion efficiency of the engine, tank/battery, and transmission in isolation of the rest of the car body. Another way to put this: if you manage to buy an electric Hummer, you are going to be spending an insane amount of time charging it, because it would use as much more electricity as it uses more gas ;P. If you really need to estimate this using miles per gallon, you need to look at a gasoline-powered car which looks like a Tesla (being about the same size and contour), not the average new car purchased by a consumer. (FWIW, a quick eyeball of this is looking like 40 mpg.)
When the model 3 comes out, we'll be able to make better comparisons to high mpg ICEs like the fit, fiesta and civic.
In terms of real-world power usage you're close to 1/3rd of that(unless the car captures the excess heat and reuses it).
I'm all for pure-electric cars but we're still a long way from Joe the miner in Kentucky from being able to drop $1800 on a 2000 Toyota Tundra and having it be able to get him reliably from the jobsite and back. That's not even factoring in the whole capacity-decrease-with-use (and even non-use-- deterioration occurs simply by just storing cells at full capacity for long duration -- of lithium.
Even with the best, most conservative profiles on a battery-module controller for anything lithium based, good luck getting > %50 of cell capacity 5 years down the road of a daily driver [edit: 7]. Anode deterioration (at least, last I seriously researched it for projects requiring portable units for driving larger loads than an average car was ~1.5 years ago) was still a problem even in the lab.[3]
My sister abuses her 2004 Civic coupe to the point where I think she's still running a stock air filter and runs 30-35k between oil changes[4]. This was a run of the mill car she's had since god-knows-how-long and she's still getting 22mpg city [5] ~26 highway on an automatic transmission.
tl;dr -- In terms of total costs :
- capital (purchase) / delivery fee
- operational ($ of petrol for ICE per unit travelled/$ of energy from your power supplier per kw/h), insurance
- maintenance (tire wear, brakes, battery module(s) replacement(s)) over, eh, 5 years from out-of-the-showroom-into-your-garage, I'd be surprised if you saw the electric dollar-for-mile-traveled outperform it's ICE counterpart.[6] I'm far from the forefront of Li, but I do have a few friends in that field (both in academia and in industry) -- even the most optimistic don't see pure-electrics reaching a TCO parity point of an ICE for the consumer in less than 10 years.
--
[1] http://www.greencarreports.com/news/1091436_toyota-gasoline-...
[2] https://www.youtube.com/watch?v=FJXgKY2O4po FreeValve as explained by that really enthusiastic "Engineering Explained" 24 year old automotive engineer, dumbed down to the point where even I can grok it.
[3] Rumor had it, DARPA was using some crazy proprietary stuff that managed to completely nullify dentrification, but if they've managed to accomplish that anodic behavior, there's no way it's going to be released for public usage -- rather, it'll remain hush-hush minus 50 PhD's in metallurgy, and Lockheed drones all of a sudden posting performance numbers +30% from the last revision.
[4] She's not using those long-lasting synthetics that have additives to SeaFoam (yeah, I'm using it as a verb) out carbon build-up on the cylinders and what not, in case you're wondering. Just cheapo 5w/30.
[5] That, albeit was with me driving in 'conservative' mode rather than "hmm let's see the 0-160 on this McLaren".
[6] And I'm 100% sure if you bought a 3 year old variant of an ICE vs a pure-electric, it's no contest -- vvanders ↗ Not sure where your getting your 50% degradation numbers from, I have 2 years of daily use, 43k miles and only ~2% degradation. iheartmemcache ↗ (old-ish study, apologies, but was cutting edge circa 2010, but still stands re: LiFePO2 which I'm betting your '14 production car is using) -> http://ecec.mne.psu.edu/pubs/2010-zhang-jps.pdf Page 2, Column 2, Figure 1, Top chart. 300 deep-cycles @ ~92%, 600 @ 74%. vvanders ↗ If by daily driver you mean weekly 300mi weekly roundtrip that usually ends around 5-10% and ~30 miles a day otherwise then sure. toomuchtodo ↗ Tesloop, the transport company that'll shuttle you between LA and Las Vegas via Model S, has only seen 6% degradation over 180k miles on their vehicle; this is with ignoring Tesla's advice not to charge to 100% every time at Superchargers. [deleted] ↗ (comment deleted) maratd ↗ > good luck getting > %50 of cell capacity 5 years down the road of a daily driver antisthenes ↗ > After 10 years, I expect to have >80% of capacity still usable. vvanders ↗ Capacity loss for leafs come from their lack of thermal management, not driving range. See the issues they have with capacity in warm climates. maratd ↗ > but most importantly of the number of recharge cycles.
If you're the average SV guy who 'daily drives' his Tesla 20 miles from Oakland to his lofted startup where there's 220 to full-charge before you go home, you'll get 2%. Johnny in Kentucky working the coal miles doesn't have that luxury and will certainly enter into 'deep charge' consumption. (600 cycles -> ~75%, with 2nd deriv of batt life w/r/t cycle being negative, i.e., progressively decreasing losses).
Again, not in the field professionally, but these opinions are consistent with my friends who are working at the forefront (albeit, a statistically small sample space, I openly concede !)
My numbers line up with what most Tesla owner experiences. If your friends are at the forefront of the profession then I'd be a bit worried about whoever they're working for.
Your pack longevity math is grossly inaccurate.
The data doesn't bear this out. Users have been seeing 5%-10% degradation over the first few years, after which point it levels out.
After 10 years, I expect to have >80% of capacity still usable.
The enemy of lithium ion is high state of charge, as you said, and high temperature. Tesla gives you control over how much you charge the battery, so you can easily avoid a high state of charge.
The big deal is temperature. Your laptop, cell, power drill, etc. do not have temperature control. The battery overheats frequently and capacity suffers, until the battery is dead. Tesla has an active liquid temperature control system in the battery pack. It cools the battery when it heats up and heats it up when the pack is cold, keeping the temperature under control. This preserves capacity long-term.
It's pointless to talk about capacity at year X without accounting for range, your driving habits and miles/year.
Capacity loss is not a dependent variable of just time, but most importantly of the number of recharge cycles. This is why Nissan Leaves (especially 1st gen ones) have experienced huge capacity losses when used as daily drivers (think 30% loss @ 50,000 miles). Depending on how long it takes you to drive 50,000 miles, the time frame can be as short as 3 years.
Of course a Tesla needs fewer charges to go 50,000 miles, but that obviously comes with a huge price premium over the 'economy EV' like a Leaf or a Kia Soul or what have you.
That was the point I was alluding to. You're mistaken in thinking that this is the most important factor. It isn't. The most important factors are extreme states of charge and temperature. If you account for those and control those, you can easily go a million miles on the battery pack without any kind of major issues. The rest of the car will fall apart before the battery pack gives out or suffers major degradation.
Its also more reasonable to tap into overnight power as to not stress the daytime powergrid.
>gas contains about 33kWh of energy per gallon
ICE are about 20-30% efficient. So 70% of that 33kwh is lost to heat and other inefficiences. Electric cars are about 70-80% efficient, so you actually need only 1/3rd the energy capacity in this kind of calculation to match ICE/gas.
Most of the time my LEAF gets charged at home in my garage. We only use public chargers a handful of times per year. When we do, it's stations in parking garages or public parking lots. Which means we plug it in and walk away. We don't have to stand there with it while it charges. If it takes a couple hours that's fine.
People focus on how fast they can recharge their EVs while they are standing there waiting for them because they are used to having to go somewhere to refuel their gasoline powered car. One of the great things about owning an EV is you recharge at home.
One of the beauties of EVs is not having to use that style of system. The superchargers are nice but most of the time you won't use one unless you're regularly driving over 200 miles a day.
Apparently people leaving Teslas longer than necessary in the supercharger spots is already an issue [1] that they are trying to rectify by charging for overstays.
[1] https://news.ycombinator.com/item?id=13204120#13204455
But that is a very small percentage of people. If only those people bought gasoline cars in 2017 they would sell fewer than the number of EV cars sold in 2016.
https://www.reddit.com/r/teslamotors/comments/4u0yci/why_i_w...
I agree though that swapping and slower charging would make more sense than trying to charge at some multimegawatt level to reduce the cargo transit time.
There is plenty of time to recharge a truck over night at a truck stop. The issue is gonna be infrastructure at the truck stops. I am gonna guess at 150-300 spaces at most truck stops. If the majority of trucks go electric then I am not sure the electric grid's connection to the truck stop is gonna be able to support that.
Anybody know the math on how much electricity would be needed to take an 80,000lb truck 700 miles? (700 miles would be on the very upper end of the scale but you want that kind of range to accommodate for climbing hills with a full load.) And after that the math for charging say 100-200 of them? (I doubt the truck stops will all be charging at once)
Superfast chargers would be great for self-driving trucks making long distance trips. But then, train corridors probably beat those on every way.
For vehicles where somebody is inside, I don't really see the point of 5 minutes charging. People need to rest and eat, and nobody does that in 5 minutes. Plentiful slower chargers would be a much better selling proposition.
A gas fuel tank under a service station, however, is cheap, and is limited only by the size of the forecourt in how many cars it can simultaneously service. And we still have the problem of charging time. You'd probably talking a forecourt capable of charging 100-200 cars simultaneously during peak times. That's 60-120 megawatts on Musk's fast charge. That's enormous. It's an entire small power station.
For any long distance, my sense is that electric cars are still at a heavy disadvantage to the ICE for the foreseeable future, even assuming Musk's optimistic charging cycle projections.
Let's face it, gasoline still has some miraculous energy storage density / transportability advantages.
It could happen for some popular routes, but it will be a minor nuisance and easily fixed with more supercharging stations on the routes that are more congested.
You need a way to force a car to start charging while parked in special spots, and force it to leave when done (the Tesla actually could move itself out of the way automatically, if only there weren’t a charging cable attached).
I doubt that they want to start supercharging at higher voltage. A DC-DC converter at that scale will be fairly large. I suppose they could add some contactors internal to the battery pack to change the cell wiring to double the voltage and halve the current for charging purposes.
In the above case, they used liquid cooling to make the charging cable diameter smaller, but perhaps the technology can be used to make the regular Supercharger cable capable of handling more power.
There is ~56 weeks in a year, so with that kind of use you get 10 years worth of deep cycles (600)
The light ones were shown already to have basically no impact.
Meanwhile, in real world people have harsher climates that will screw with the batteries even further - where I live summer goes to 35-40C and winter can go as low as -20-25C
Also, current "normal" electrical grid is not capable of charging dozens of cars at the same time, even with slow charging
Any medium business can have 50 or more cars parked and I higly doubt they will go to the trouble of upgrading their power connection by an order of magnitude -> which means no one working there will even consider an electric car
Sure, I'd love to have an electric car to do my daily commute (total of 10 miles), but since those are so riddiculously expensive, unsuitable for my climate and depreciate riddiculously quick it's kind of a moot point
We detached this comment from https://news.ycombinator.com/item?id=13264454 and marked it off-topic.