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.
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.
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 -- https://www.edmunds.com/car-buying/drive-a-nearly-new-car-fo... -- ignore the link bait title, it's just about the FMV of cars as a function of time.
[7] In addition to the response I made directly to child-poster, I'd like to concede that it is very possible he's ran 43k miles (i.e., literally at least a thousand cycles, likely closer to mid thousands) with a retained 98%. He makes a very valid point in bringing up the variance of cell capacity deterioration. I'd genuinely love to see some cal'd equipment with your standard dummy load and power analyzer log setup to see the data. (I ain't no fancy electron whiz but I can read me a chart or two.)
The take away is that overall capacity is a function of usage. I could probably get in the lab and simulate 43k miles of load in LabView discharging/recharging every 10 miles while keeping the thermal properties controlled as all heck and see 99.5 capacity retention, but these, again, aren't Joe's driving patterns.
edit 2: @maratd: See my edit 1/[7] (which I presume I was writing while you were drafting your response). I think we're largely in agreement re: usage properties being highly influential. My response to the OC (original child poster) addresses the deep-cycling cooling. As this has turned into a post with 8 endnotes, I think I've crossed the threshold of reasonable discourse.
Allow me to close with a quick remark re: BMC's on your power drill. Anything half decent will have active thermal monitoring specifically because of the reason you stated (much to the chagrin of blue-collar workers everywhere). "Ok, last weld before quittin' time..." paddle trigger actuates, worker expects wire-wheel to start spinning a to clean the slag of iron oxide off the root weld. nothing happens because the thermocouple on the motor armature triggered a lock-out "PC LOAD LETTER WHAT THE HELL DOES THAT MEAN?"
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.
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.
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.