Battery Technology

Darell

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Are those the batteries which have about half the energy density of lead acid? They're somewhat useful in cars as their high charge rate can capture energy from braking... but I didn't think that was a big problem for big batteries.
We can't regenerate enough energy to overwhelm any of our current battery chemistries. The X1 will go 0-100-0 in eleven seconds without using any friction brakes (until the last few mph)! All regen energy is just stuffed back into the Li-ion batteries. Me thinks that we don't need more than that!

I remember someone saying recently it took about ten years for the last doubling of lithium battery capacity.
Here's a chart that's a few years old that'll show some energy density values for various chemistries.
http://www.madkatz.com/ev/batteryTechnologyComparison.html

Just imagine if energy density for gasoline would double every five or ten years!
 

jzmtl

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First off, I haven't had an EV that was slower then your Jeep. Secondly, the performance car and the "$150,000 cheaper" car were one and the same. For $100,000 you can have an EV that'll beat cars that cost $250,000.


Let me know when you have a question for which you don't already have an answer.

You can't buy "consumer" EVs today. They don't exist. This is why I do what I do - trying to dispell the misinformation that's out there. I own a consumer EV. I know what they're capable of. In mass quantities, the car I'm driving today would cost about $30,000 to buy. I don't know what else to say... You obviously *really* don't like BEVs for some reason. Good news! You don't have to drive one. All I ask is that you stop propagating the stuff you dont' know about.

Oh... and this topic started about vehicle batteries, and probably belongs in the CAFE. I think I'll move it before somebody complains and wants to slap me.

I'm not asking you any questions. I do not hate or like EV but I don't like your twisting arguments.

Your $100k performance ev is exactly my point, for that price it's in supercar territory (and where price is not proportional to performance), how many people can afford a car cost that much? How about we talk cars with prices that's at least in the same ballpark figure, that people can actually afford, with specific examples? Let's take your $30k EV that's faster than my jeep, and show me hard data on its performance.
 
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Darell

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I'm not asking you any questions.
I was thrown by the question mark.
jzmtl said:
And how much do they cost?

And there are several more questions for me in the current post. I'll get to those later.

I don't like your twisting arguments.
The argument that you accuse me of twisting is this:

jzmtl said:
Then there's the problem of power, some people like vehicles with decent power, not floor the pedal and read a book before it reaches highway speed.

To that statment I replied that we have electric cars that go faster than gas cars. No twisting involved. You say EVs are not fast enough. I say they're faster than equivalent gas cars. Now, apparently you'd like the performance at a reasonable price. (as you mentioned later with the Mazda example). Have I twisted anything yet?

jzmtl said:
Your $100k performance ev is exactly my point, for that price it's in supercar territory
Well, yes. And that is why I am comparing supercar to supercar. The reason being that we HAVE supercars in both categories that we can buy today. We do not have consumer-level EVs that we can buy today. So there is no price comparison to make. At the Supercar level, there is nothing you can buy for under $250,000 that can beat a $100,000 EV.

Anything twisted yet?

jzmtl said:
How about we talk cars with prices that's at least in the same ballpark figure, that people can actually afford, with specific examples? Let's take your $30k EV that's faster than my jeep, and show me hard data on its performance.
OK, the best I can do for you is talk about my first EV - a 1997 EV1 with lead-acid batteries. This car was designed for the 1996 model year, so we're talking about an 11-year-old vehicle today, with ancient battery technology. That car could consistently do 0-60 in 7+ seconds. I believe that the official spec for the lead model was 7.9s. Most cars (like mine!) were officially clocked faster than that. The residual value of that car after my 2-year lease was around $30k. I can't remember exactly, though I wrote a check for it to present to GMAC at one time.

But this is all academic. The cars were never sold. They would not let me buy it for the residual. Instead they took it back and crushed it with only 30,000 miles on the odometer. We can't buy these cars today - for ANY price. If they were mass produced at the same level of gas cars, the prices wouldn't be significantly different. And this doesn't even include accounting for all the hidden costs of using gasoline, of course. And for the life of the car, the fuel costs 1/5 of gasoline.

(I can't use my Rav4EV in this example because it has INCREASED in value over the five years I've owned it. So none of this is comparing apples to apples. I don't know of many other cars that have gone up in value in the first five years.)
I don't know what else to tell you. If you at least seemed a bit receptive to any of this, I might be more fun to play with.
 
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jzmtl

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It was a rhetoric question if you must ask.

In my original post I was talking about commuter cars, and how electrical version doesn't have performance. then you come throw out a $100k supercar that no one can afford and argue it does. Then I raise the question of price, you respond with even more expensive supercars that the brand alone would worth more than your electrical supercar. I'd call that twisting when you deviate further and further from original topic of commuter car to justify your own argument.

As for your EV1, I'll compare it with one of the bread and butter of commuter car, honda accord. Your number of 7.9 is about the same as 4cyl manual accord, and a 6cyl manual will come at 7 with no problem, and both cost less than $30k. Since I mentioned jeep, a grand cherokee with 4.7l engine clocks at 7.2, and we are not talking about ones with 5.7l engine.

Mazda Miata = Mazda MX5, yes? It's not quite what I'd call a high performance car, but arguably quite fun.

Yes it's MX5, but mazdaspeed version is turbocharged from factory. :D Oh yeah it clocks at 6.7 and have MSRP of $25k
 
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TorchBoy

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As for your EV1, I'll compare it with one of the bread and butter of commuter car, honda accord. Your number of 7.9 is about the same as 4cyl manual accord, and a 6cyl manual will come at 7 with no problem, and both cost less than $30k. Since I mentioned jeep, a grand cherokee with 4.7l engine clocks at 7.2, and we are not talking about ones with 5.7l engine.

Yes it's MX5, but mazdaspeed version is turbocharged from factory. :D Oh yeah it clocks at 6.7 and have MSRP of $25k
QED. :naughty:
 

jzmtl

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Eh? QED?

One thing I love about this forum is you can argue with a mod with no problem, where as some others the instant you do his gang start to flame you without knowing WTF is going on, and he threaten to ban you. :D
 

TorchBoy

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I meant it's not what I'd consider a high performance car. These days you have family cars that do not too dissimilar times and my own wagon is around there too, and a fair bit heavier at that. But they can be great fun. A friend took me for a ride a few months ago in his MX5. As we went around a sharp bend I asked him what happens if it rolls, having noticed the complete lack of any roll bars or other protection. His answer: "We die."

Sorry, that's quite off thread, but I figure this is the café. :buddies:
 

jzmtl

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But it's cheap! $25k that's same price as a medium level 4 cyl accord! Still 0 to 60 is not what it's about. Too bad at 6' I'm too tall to fit in it comfortably, or I'd buy it instead of a jeep.
 

TorchBoy

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Still 0 to 60 is not what it's about.
No, it's a total package. They've cut down in some areas (like rollover safety?) and improved other areas that make it fun to drive. And it does provide another option.

Too bad at 6' I'm too tall to fit in it comfortably, or I'd buy it instead of a jeep.
They're quite different approaches... Aren't you glad you have so many options? (Have you tried a Toyota MR2?) We just don't have that luxury for electric cars yet.
 

Brock

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Darell I think the closest thing you could do would be comparing the gasser Rav4 to your EV rav4, basically the same body, different insides. I would be curious how the gasser version compares to the EV version with stats like 0-60, range (although I know) charge time, the typical stuff.
 

Darell

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One thing I love about this forum is you can argue with a mod with no problem, where as some others the instant you do his gang start to flame you without knowing WTF is going on, and he threaten to ban you. :D

Thanks for the compliment on behalf of all the staff. We're ALL first and foremost members of this board. We do the other stuff only because somebody has to take the trash out every now and again.
 

Darell

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Darell I think the closest thing you could do would be comparing the gasser Rav4 to your EV rav4, basically the same body, different insides. I would be curious how the gasser version compares to the EV version with stats like 0-60, range (although I know) charge time, the typical stuff.

Brock -

The good news is how similar the two vehicles are. The bad news is that all this really tells us is what decisions the designers made for this fleet-specific vehicle. And it only tells us what they were thinking 12-13 years ago when it was being designed.... with 13-year-old battery technology. 13 years ago was the infancy of modern BEVs, but a very mature period for ICE, ya know?

Couple of things come to mind:
1. The Rav4EV was originally designed with on-board charging, and was capable of 50kW input charge. The production car ended up with an off-board charger, and was limited to 7kW. Were these changes made to make the car better for the consumer? More ICE-car like? Not by a long shot. Both were logical, profit-driven changes. The car was designed for, and is still capable of (given the right equipment and charging circuit) charging fully in under an hour. What we got was as car that takes five hours to charge (empty to full).

2. The original Rav4EVs were having to replace the front tires in just a few thousand miles as the fleet drivers were burning the rubber off of them (yes, this in a car with 50 peak HP... and yes I know this has nothing to do with HP, but it still shocks people to hear). Toyota quickly added a torque limiter that starts at 0mph, and is active until about 4-5mph. So from a stop, nothing much exciting happens if you floor the accelerator. After 4-5mph, it picks up nicely. The result is that 0-60 times look unimpressive. But except for not being able to smoke the tires from a stop (like I could and did with the EV1!), the car accelerates the same as other vehicles with much shorter 0-60 times.

So yeah, the numbers can be put out there. But what do they really tell us? Not much about what the car is capable of. It tells us how it was put on the street. And I again - this car was never meat for private use. It was designed specifically as a fleet vehicle for utilites - where the guys driving them don't really care much about them.

Not sure what you mean about the inside being different than the gas version. It isn't There is an additional charge control panel, and the "gas gauge" reads SOC instead. But the casual observer would not be able to tell the difference in the two cars. Here's a shot of the charge controller below the factory stereo.

rav_cup_holder_closed.jpg


I have no idea what the 0-60 time was for the gas Rav4 of that era. All I can tell you for certain is that given a rolling start (to get the EV out of the Torque limiter) the EV was faster than the gas version. This I know from practical - not academic - reality. Obviously this car was not designed to be anything close to "fast." Though with it's 50hp electric motor, it has never left me wanting for more power. The answer, of course, is in the superior torque curve of electric motors. And bigger motors just don't cost all that much more than smaller ones. If somebody wanted the Rav to go faster, it wouldn't have taken much to give it more power. But that wasn't the decision made at the time.
 
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Darell

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You didn't mention range. Brock may know, but others of us are ignorant and willing to learn.

Ah, sorry! Well, just for completeness and ease of learning, please realize that damn-near everything I type about EVs can be found on my EV pages (linked under my sig). When I learn something new, I try to keep it on my pages. I update my EV pages once/day on average, so there's always something new. I have a google search function on the front page (will work better - I just changed domains, and Google is slowly re-crawling my pages).

Now... for an answer: The official range is listed as 125 miles. I typically tell people 100 miles, since you have to drive quite conservatively to get 125. My record is 133 miles on a charge. This range is in a car that is built like a mildly-rounded barn door, and using 13-year-old battery technology. Think about the size of the battery in cell phones 13 years ago as compared to what you have now. And you can quickly realize how many things would have/could have been different in EVs today!

Gotta submit while CPF is still running!
 

TorchBoy

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Think about the size of the battery in cell phones 13 years ago as compared to what you have now. And you can quickly realize how many things would have/could have been different in EVs today!
Yeah. What a waste. A shameful, pathetic waste. The next 13 years won't be so wasted though - people are beginning to realise we need to move on the issue.

What's the optimum speed for an EV to get the best range? 80km/h seems to be the most fuel efficient for an ICE.
 

Darell

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What's the optimum speed for an EV to get the best range? 80km/h seems to be the most fuel efficient for an ICE.

Optimum for an ICE vehicle is as much dependent on gearing as it is wind resistance. an ICE can only be at its most efficient in a narrow operating band (RPM, valve timing, throttle position, etc). In an EV it has *everything* to do with air resistance (given a constant speed). An electric motor is almost equally efficient over its entire operating range. So you have to go fast enough to minimize the rolling resistance and other parasitic losses (like running the electronics) - but slow enough to minimize the air resistance. For most production EVs the sweet spot is between 35 and 45 mph. But that depends on the shape of the car. The sweet spot for the barn-door Rav is closer to 35, while the EV1's best was up near 45.
 

Brock

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By inside I meant engine, well anything inside the "body" of the car particularly under the hood :)

Again I know the answer, but a gasser Rav4 gets what 25mpg if your lucky. So it cost about $3.00 in fuel (or what ever a gallon is when you read this) to go 25 miles. If you were paying for electricity to go 25 miles how much would that be at say $.10 kw or even $.20 a kw?
 
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