This is what it's like to live with the Nissan Leaf

[wtmusic]

"The Leaf is not a small car. It easily dwarfs our e30 3 Series BMW and the Nissan Cube it replaced. It is no surprise that it is classified as a midsize car – it is certainly neither a subcompact nor even a compact. It is also not particularly attractive, inside or out, but that's no surprise based on all the pictures that people are used to seeing. Its real-world size, however, can be a bit surprising for those expecting a car the size of a Mini or even a Volkswagen Golf.

Our real world range has been between 70-100 miles with an indicated 105-110 miles at full charge.

Top speed is just north of 90 miles per hour and it will reach its terminal velocity relatively effortlessly with no audible or tactile reluctance. Be ready for a profound impact on range driving at those speeds for any length of time, though. The biggest range killer, BTW, is not speed, not climate control, and certainly not stop-and-go driving (this is actually where an EV is completely the opposite of an ICE car – it hates steady state, but thrives in stop and go traffic jams). The biggest range killer is hills. Long uphill sections are the Leaf's nemeses."

http://green.autoblog.com/2011/05/02/this-is-what-its-like-to-live-with-the-nissan-leaf/

I would concur with this assessment except for handling, which IMO is exceptional for the price point.

[defendandprotect]

1. k

[sinkingfeeling]

2. I'd get one if I could afford the price tag. My state offers no tax credit and will probably be one

of the last to have 'charging stations'.

[wtmusic]

3. I don't believe public charging stations will be that common anywhere.

You will probably see them in shopping mall garages, commuter parking lots, and a few other places. But in most situations charging stations don't solve the "problem" of giving you a convenience fill-up anyway - it takes too long.

As an owner, what I'm finding actually happens is it gets charged at night, and driven less than 100 miles during the day. Even with that limitation it's a completely practical and useful vehicle.

I have to admit if it wasn't for generous credits, I probably would not have bought.

[phleshdef]

5. There won't be charging stations. There will instead be battery exchanges. Like propane tanks...

...for gas grills. You will drive up, take out the battery, exchange it for a fully charged battery, the business you exchanged it at will have those batteries picked up and taken somewhere to be recharged. Gas stations and grocery stores all over the country do this same thing with propane tanks. So it won't be some grand new thing that they'll need to figure out. The concept is already in action.

[wtmusic]

8. That's Shai Agassi's vision

A little hard to know if that will be more practical than quick charging, which costs a lot less for the station owners and doesn't involve carting around 450-lb batteries.

[phleshdef]

10. Gasoline is carted out to stations now. Propane gas tanks are carted back and forth now.

Its perfectly practical. Its not any different than the logistics involved in getting energy into our cars now. No matter what we use, someone is gonna have to drive a big truck to get it from the source to the destination where consumers can access it.

I would hope the batteries can weigh considerably less than 450 lbs though, at that weight, I can see some problems. We need much lighter batteries than that.

[Nederland]

18. I don't think so

Battery technology is still improving at a fairly rapid pace, and battery swaps are only necessary with the current level of technology. Right now, cars like the Leaf makes a fine second vehicle or even primary vehicle for certain people. That is a huge market, and not one that will be fulfilled rapidly. As a result, car makers can continue to make these cars profitably and work out the usual issues that come with new technology while batteries inevitably get better and better. In ten years time, I suspect battery packs will be able to provide a 500 to 700 mile range, which effectively renders the range issue moot. Very few people drive more than that in a single day, even when travelling, and so at that point all you need is for hotels to provide charging services for people to use while they sleep.

[Tesha]

22. Unless the technology switches to "flow batteries"...

(batteries with replaceable liquid reactants not too-unlike
a fuel cell), 5-minute recharges will *NEVER* be
practical; the required power levels are just too
high, far beyond the capabilities of practical cables
and connectors.

Battery swapping or flow batteries are the enabling
technologies for "fast recharges".

Tesha

[Nederland]

24. Missing the point

If battery packs can provide a 500-700 mile range why would you ever need a 5-minute charge? You have to go to sleep at some point, so do your charging then. I suppose there are a few odd situations or use cases where you would need something like that, but I don't think the number of situations that fit that scenario will be able to justify the construction of the huge battery swapping infrastructure you are envisioning. The demand will simply be too low.

[Tesha]

26. I'm unclear on how electrochemistry, as we understand it, gets one to a "500-700" mile range.

Lithium batteries are nearly as good as it can get,
electrochemistry-wise; there simply aren't many other
reactions we could exploit that are more-energetic per
unit mass.

Given that, the only other degree of freedom that exists
to exploit is the Cd (drag coefficient) of the car, but barring
a miracle, we're pushing the boundaries there as well.
(Maybe not with the Leaf, but as was mentioned above,
the EV-1 pushed that about as hard as you can for a
practical car and it was only somewhat better.)

And as I pointed out in my "how high can a battery lift
itself?" reply, after a certain point, adding more battery
to the car becomes asymptotically unproductive.

I just can't see where the long-range BEV comes from
absent battery swapping technology or the exploitation
of flow batteries; it's not that we haven't discovered/
invented some necessary piece of technology, it's that
we're bumping the basic physical limits of the system.

Tesha

P.S.: As you might guess, I'd *LOVE* to be proven wrong!

[Nederland]

30. That is the weak part in my argument

We've all heard about things that work well in a lab but never seem to become commercialized to work in the real world. That said, the most promising battery developments I've heard about concern Metal/Air batteries. The trick with these is to use oxygen as one of the elements in your battery chemistry. When you do this, you dramatically reduce the weight of your battery because half of the material you need for your electro-chemical reaction simply comes from the atmosphere. For example, the theoretical energy density for a Lithium-Air battery is 11,140 Wh/kg, which is over 25 times the energy density of current Li-Ion batteries. Most impressively, it is 40.1 megajoules per kilogram, which is nearly the same as gasoline (44 megajoules per kilogram).

Now I realize you are never going to get to that theoretical limit of 25 times better than Li-Ion. However, if the Leaf is already at 100 miles per charge, obviously all you really need is something that has 5-7 times the energy density before you reach the 500-700 mile range I was referring to. Will it happen? Who knows. I hope so!

Good summary here: http://en.wikipedia.org/wiki/Lithium_air_battery

And more here: http://www.sciencedaily.com/releases/2009/05/090517152557.htm

[Tesha]

33. I agree that xxx-air chemistries are more energetic, but...

...they have the disadvantage that the working materials
tend to dry out. That's no real downside in, say, zinc-air
hearing aid batteries because they're one-shot disposable
batteries, but it's a real problem in a secondary battery
that must remain operational cycle after cycle.

I would imagine it would yield to technology, though,
with the car perhaps carrying a small tank of DI or
distilled water and a suitable battery-rehydration
system.

Tesha

[Starboard Tack]

44. Whatever happened to the All-polymer Plastic Battery

developed at Johns Hopkins back in the 1990's?. I thought this would be the wave of the future, as cars could be built out of this material. So the entire car body would, in effect, be a battery

[wtmusic]

29. "5-minute recharges will never be practical"

Lots of promising research in that area (nanoscale structuring).

"Of all the criticisms of electric vehicles, probably the most commonly-heard is that their batteries take too long to recharge – after all, limited range wouldn't be such a big deal if the cars could be juiced up while out and about, in just a few minutes. Well, while no one is promising anything, new batteries developed at the University of Illinois, Urbana-Champaign do indeed look like they might be a step very much in the right direction. They are said to offer all the advantages of capacitors and batteries, in one unit.

"This system that we have gives you capacitor-like power with battery-like energy," said U Illinois' Paul Braun, a professor of materials science and engineering. "Most capacitors store very little energy. They can release it very fast, but they can't hold much. Most batteries store a reasonably large amount of energy, but they can't provide or receive energy rapidly. This does both."

The speed at which conventional batteries are able to charge or discharge can be dramatically increased by changing the form of their active material into a thin film, but such films have typically lacked the volume to be able to store a significant amount of energy. In the case of Braun's batteries, however, that thin film has been formed into a three-dimensional structure, thus increasing its storage capacity."

http://www.gizmag.com/3d-thin-film-batteries-recharge-in-minutes/18187/

[Tesha]

32. It ain't especially a question of how quickly the battery can accept power, though that's...

...doubtless important. It's a question of cables and
connectors.

If we assume that a BEV manages 250 WH/mile, and has a
range of (say) 200 miles, then you have to move 50,000
WattHours into the car in five minutes. Since you're doing
it in 1/12 of an hour, the power level has to be 600,000
Watts.

If you're moving the power at 600 Volts, that's 1,000 Amps.
That requires one Hell of a connector and no easy-mating,
long-lived connectors exist at that amperage. Connectors
exist, but they require significant routine maintenance
and have very high mate/demate forces. (Look around on
DU; I posted some pictures and manufacturer data sheets
a few months ago).

Alternatively, you could design the connector to work
at more-reasonable current levels but the voltage level
will rise *VERY* high, for example, to get you to 100
Amps, you'll need to operate at 6,000 Volts. Good luck
getting regulatory approval for *THAT ONE*!

Here's the standard BEV connector:

http://en.wikipedia.org/wiki/SAE_J1772



It's rated at 7.7 KW today, although there is hope
of more than doubling that in the future. At today's
power levels, it can deliver a mile of electricity
about every two minutes, so our 200 mile car will
require almost seven hours to recharge.

Tesha

[wtmusic]

35. 192 KW, 480V DC charging is optional for Leafs right now

Charges to 80% in 1/2 hour:

http://www.evtown.org/about-ev-town/ev-charging/charging-levels.html

Charging it in 5 minutes would require an even heftier connection, but there's nothing technologically insurmountable about it. It would probably use some kind of parallel connection scheme.

[Tesha]

37. And you also violated my "200 mile" assumption.

The Leaf is more like a third of that value.
So we have 80% charge of our hypothetical 200
mile car in one hour.

That's quite a ways from the "5 minute" charge
that I claimed couldn't be achieved.

By the way, here's an interesting statement about
"Level three" chargers (emphasis added):

http://planet.betterplace.com/profiles/blogs/electric-charging-stations

B.3 Level 3 Charging
Still under development, these fast-fill chargers are expected
to recharge 50 percent of an EV’s battery capacity in 10 minutes
or less. Level 3 systems will rely on an off-board charger that
converts AC to DC. The high power involved in Level 3 Charging
(480-Volt, three-phase electric service) is beyond the capacity
of most utility transformers that serve residential areas and
even some that serve commercial areas. Utility distribution
system upgrades may be required to accommodate
Level 3 charging.

Here's the charging connector for CHAdeMO, by the way.
Looks delightful, doesn't it? Do you think everyone will
be able to hoist it and connect it?

http://en.wikipedia.org/wiki/CHAdeMO



Tesha

[wtmusic]

39. Old information

The dealer where I bought my Leaf has a Level 3 charger.

I was incorrect about the rate; it charges to 80% in under 20 minutes.

http://www.evtown.org/about-ev-town/ev-charging/charging-levels.html

My Leaf gets an average of 85 miles/charge (I have no idea how you arrive at 66 miles) so 85*.8 = 68 miles in 20 minutes. It's hard on the batteries, but again - there's nothing theoretical about connectors/cables which is preventing 5-minute charges.

You claimed the 5-minute charge couldn't be achieved in an earlier post then qualified it by introducting the arbitrary 200-mile range afterward. Not sure why you're intent on disparaging EVs, the reality is much more encouraging than you suggest.

[Tesha]

43. I have no interest whatsoever in "disparaging electric cars".

In fact, as our Dodge Caravan comes nearer and nearer
to finally falling to pieces, we'd very much like to be able
to replace it with a BEV or, failing that, a hybrid or a diesel.

But *NO ONE* should buy a BEV assuming that they will
*EVER* be able to recharge their car in five minutes. It certainly
can't happen with today's cars and it is extremely unlikey,
barring the development of room-temperature superconductors,
to happen any time in the future either.

Standardized battery swapping or flow batteries are the only
routes to the ideal "five minute refill".

I just want folks to have correctly-set expectations.

Tesha

[wtmusic]

40. That connector spooks you, but swapping a 450-lb. battery doesn't.

OK Tesha...whatever. :eyes:

[Tesha]

41. The battery swap, if it evers occurs, will be automated.

But somehow you expect little old ladies to tote
that connector and the copper cable dangling from
it. This cable is as thick as a gasoline hose but
copper weighs a lot more than does gasoline.

Tesha

[Nihil]

42. Beg to differ

> The battery swap, if it evers occurs, will be automated.
> But somehow you expect little old ladies to tote
> that connector and the copper cable dangling from it.

Both of them would probably lead to a return of serviced "pumps"
rather than self-service.

The battery-swap option (iieo) cannot be fully automated
as it would require an operator for the transportation side
(even if not for the uncoupling/coupling stage).

Having a person around to assist the connection for those who
require it will be just one step from having the person around
full time (and helping with the old-fashioned fuel pumps too).

Job growth industry! :-)

[Nederland]

25. Agreed, except maybe hotels

People traveling long distances will stop for the night and need to recharge their vehicle for the next day of travel.

[oldhippie]

4. I have to wonder about this, though ....

"The biggest range killer, BTW, is not speed, not climate control, and certainly not stop-and-go driving (this is actually where an EV is completely the opposite of an ICE car – it hates steady state, but thrives in stop and go traffic jams)."

I wonder how that is? It still takes more energy to accelerate the mass back up to speed from a stop. More so than the energy it takes to maintain speed overcoming rolling and wind resistance at the same speeds. Even though with regen braking you can recover some of the energy, the process is not 100% efficient. So I wonder how stop and go is killing range vs. steady state? It doesn't make sense to this engineer. Anybody got an idea?

[Kber]

6. Don't know for sure, but if it's like the Prius, you get energy from breaking

and coasting.

Just a guess.

[wtmusic]

7. Peukert's Law

presented by the German scientist W. Peukert in 1897, expresses the capacity of a lead-acid battery in terms of the rate at which it is discharged. As the rate increases, the battery's available capacity decreases."

http://en.wikipedia.org/wiki/Peukert%27s_law

It's a characteristic of chemical batteries which was derived empirically, and I don't know if a satisfactory explanation for why it happens even exists.

[wtmusic]

12. Actually the explanation is fairly simple - resistance.

Resistance = voltage / current. Since current is a function of time, (1 ampere = 6.241 × 10^18 electrons passing a point in a wire each second) if you push the same number of electrons past a point faster it creates more resistance, and more energy is dissipated as heat.

Had to think about that one a minute.

[IDemo]

31. Confusing cause and effect

Current flow doesn't directly increase resistance. An increase in current can result in heating the conductor, depending on which material is used, which raises its resistance. The result will be an increase in energy lost as heat, unless the material is a super-conductor or has a "negative temperature coefficient".

[lfairban]

17. Not really

Peukert's law is only significant for Lead-Acid batteries. The Leaf uses Lithium Ion batteries.

I thought the statement odd myself. It could be because the only steady state driving we do is at higher speeds. It doesn't hate steady state, it is just not as comparatively good at it.

[Tesha]

16. Air resistance rises as something like the cube of velocity.

In an ICE car, there's some point where you reach
an optimum between the idling losses of the engine
and the rapidly-increasing air resistance of the
car; that's the point where you'll get the best
mileage. (Often, it's 40 or 50 MPH.)

By comparison, there are essentially no idling
losses for the BEV, so the lower the speed, the
more distance it can make per unit charge. Perhaps
it doesn't actually *LIKE* stop-and-go, but two
MPH probably suits it fine as long as you're not
heating or air conditioning at the same time.

Tesha

[wtmusic]

20. Good points - and more info on Peukert effect with relation to Li-Ion

The Leaf is not that aerodynamic; compare its drag coefficient (.29) to the original GM EV1, the most streamlined production car in history (.18). So that likely has a lot to do with it.

And with ICE another factor would be torque characteristics, which make it more efficient at highway speeds.

Searching for data on Peukert's effect with Li-Ion was a challenge. All roads lead to a 2005 paper titled, "A critical review of using the Peukert equation for determining the remaining capacity of lead-acid and lithium-ion batteries" (costs $39.95). Quoting under fair use:

"Fig. 4 reveals that for the tested large high-energy lithium-ion cell, the dischargeable capacities are between 30 and 32 Ah in all tests regardless the discharge rate. This can be explained with the rise in cell temperature to almost 55◦C during the continuous high rate discharge, which is known to enhance the performance of a lithium-ion cell. In contrast, the temperature at low rate discharge stays at about 25°C as shown in Fig. 4. If the battery is discharged at a high current, while the battery temperature is maintained at 25°C, then it is expected that the available capacity will be reduced."

http://linkinghub.elsevier.com/retrieve/pii/S0378775305007093

So if the batteries are allowed to rise in temperature to 131°F you get nearly as much energy no matter how hard you drive them. However, the battery temperature gauge on the dash shows that pack temperature remains fairly steady - and the car actually loses energy because of it.

Another effect evident on the graph in the paper is that voltage drops precipitously under high load at first, then flattens out. Which is maybe why I see the miles ticking off my range when I hit a freeway onramp.

[madokie]

19. I thought it said that the range killer was long hills

[damntexdem]

9. Just don't roll it.

You wouldn't want to turn over a new Leaf. ;-)

[Sherman A1]

14. Great!

:rofl:

[Nihil]

21. Bad dtd!

:spank:

[phantom power]

11. Hills. interesting.

[Sherman A1]

13. I would love one

I wanted a Prius, but bought a Yaris as that is what I could afford. Been getting 40 - 42 mpg on my mixed highway/street commute so while not perfect, it is far better than the 19mpg I got with my 98 Ranger which is now semi-retired for use around the neighborhood.

[Tesha]

15. One of the more-interesting measures of a battery's (or a fuel's) energy density...

...is how high it can lift itself before running dead/
running out.

I haven't run the numbers lately, but IIRC, the numbers
for an old lead-acid battery are stunningly awful;
something like 800 feet.

Modern batteries are much better, both because they are
lighter (made of lithium) and because they store much
more energy, but it's still no surprise that hills are
the Leaf's biggest enemy.

By comparison, a gasoline-powered car can climb
thousands of feet (to the top of the Rockies, say).
Gasoline has amazing energy density. Practically
the only way to do better would be nuclear power.

Tesha

[Kablooie]

23. Erk. I live up a steep 2 mile hill. Looks like I'm stuck with gaoline for awhile.

I have a Prius though and it does fine on our hill.
I get around 47MPH overall.

[Tesha]

27. We're in exactly tht situation!

We live at the top of roughly a 250-300 foot
gradient. If we arrive at our neighborhood without
300 upward feet worth of energy in the battery,
we're gonna need a couple of thousand feet of
extension cord.

On average drives (like Mr. Tesha's daily commute),
that last climb sucks about one Mile-Per-Gallon or
more off of the trip's average fuel economy.

Tesha

[wtmusic]

28. That would be no problem.

You'd see your range shed about 10 miles on the climb - then get most of it back when you go down.

[Tesha]

34. Assuming you ever made it to the top, of course. (NT)

[wtmusic]

36. Have you run out of gas on your hill? nt

[Tesha]

38. As I mentioned, gasoline is *VERY* energy-dense compared to any battery. (NT)