Battery Technology

Darell

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By inside I meant engine, well anything inside the "body" of the car particularly under the hood :)
Ah! See with just a bit of help, we eventually understand each other. I love these cut-away drawings done by Kevin Hulsey (who has allowed me to host them on my site). That's the entire drive train. No gas tank or exhaust, of course. And look at that complicated transmission! Oops. There isn't one. The big box under the hood is where the controller is (along with some very large fuses and capacitors - but it is mostly empty now since that is also where the charger used to be.

rav4ev_cutaway_lg_wt.jpg


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?

Lots of ways to look at this.

I think you are right on the money with assuming 25mpg for the gas version. And we'll be generous and say $3/gallon gas. So that's 12c/mile (just for the gas mind you. We're ignoring oil changes and tune ups, of course)

The Rav does about 250 Wh/mile from the batteries. I'll be generous and go 300 Wh/mile from the outlet. That's 3.33 miles for every kWh you buy. At 10c/kWh we're talking about 3c/mile in electricity. at 20c/kWh we're obviously twice that at 6c/mile. So worst case scenario for the EV is half the cost of the best case for the gas car.

But of course when you figure in Time of Use metering, and pay just 5c/kWh like we do here during off-peak times... surprise! 1.5c/mile in fuel.

But then we all know that this isn't just about the money, now is it? :) My car holds the energy equivalent of about one gallon of gas. And on that one gallon of gas worth of energy, it can silently travel over 100 miles.
 
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LukeA

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Thanks solely to you, Darell, I have been pining for an electric Ranger for the past 4 months. There's usually one on eBay Motors. Like the (lead-acid) one now with 3 days left and a bid of $8100. I know the NiMH is better, but...
 

Darell

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Thanks solely to you, Darell
Hmm. There's a fine line between thanks and blame, eh? :)

I have been pining for an electric Ranger for the past 4 months. There's usually one on eBay Motors. Like the (lead-acid) one now with 3 days left and a bid of $8100. I know the NiMH is better, but...
As many folks know, I owned a lead Ranger for a short while. And I offer this advice: If you're going to jump into EV-ownership, and you want a pickup - look at the S10 first, and the NiMH Ranger second... and the lead ranger third. The NiMH trucks are more expensive for sure... and also probably a better value. The pba batteries that Ford used never cut the mustard. The NiMH did much better, with significantly better range and durability. The S10 is an EV1 with a pickup shell on it. Best of the bunch. The best news with ALL of these pickups is that they use the cheapest chargers available.
 

jzmtl

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And look at that complicated transmission! Oops. There isn't one. The big box under the hood is where the controller is (along with some very large fuses and capacitors - but it is mostly empty now since that is also where the charger used to be..

Wait, no transmission? so it's just one gear? how fast is the motor turning then when you are at highway speed?
 

Thujone

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Too bad at 6' I'm too tall to fit in it comfortably, or I'd buy it instead of a jeep.

:thinking: I am 6'3" and comfortably fit in an accord... perhaps you are thinking civic? or smaller? Cause I drive a Mazda Protege which is the same size as a Civic and fit very comfortably... Not sure how 6' could possibly affect your ability to fit in a mid-size car... That is barely above average male height in the US..
 

Thujone

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Wait, no transmission? so it's just one gear? how fast is the motor turning then when you are at highway speed?


A trick that the A123 drag bike uses is that they run the electrical on the dual motors in series and flip to parallel giving them two 'gears'. One of which runs twice as fast while having half as much torque. And to the rpm question.. A well balanced electric motor can rotate at VERY high rpms safely. My RC brushless motor runs in the neighborhood of 70k rpms at full tilt on my current battery.
 

jzmtl

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:thinking: I am 6'3" and comfortably fit in an accord... perhaps you are thinking civic? or smaller? Cause I drive a Mazda Protege which is the same size as a Civic and fit very comfortably... Not sure how 6' could possibly affect your ability to fit in a mid-size car... That is barely above average male height in the US..

No I was talking about miata. :) Civic no problem, that's what my parents have and I drive it all the time too. The 06 and up civic is really roomy, about the same as their previous 94 camry.

A trick that the A123 drag bike uses is that they run the electrical on the dual motors in series and flip to parallel giving them two 'gears'. One of which runs twice as fast while having half as much torque. And to the rpm question.. A well balanced electric motor can rotate at VERY high rpms safely. My RC brushless motor runs in the neighborhood of 70k rpms at full tilt on my current battery.

I'm sure they can, but seems like such a waste when it's not necessary to turn that fast. More wear on everything.
 
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Darell

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Wait, no transmission? so it's just one gear? how fast is the motor turning then when you are at highway speed?

All this info is on my site. What follows is pasted from the Rav4EV data page:

Rav4EV RPM:
Final drive ratio 9.455 to 1
P195/80R16 Tires are rated at 733 revs per mile
Motor speed @ 60 mph = 733 * 9.455 = 6,931 rpm
Motor speed @ 1 mph = 6,931/60 = 115 rpm
Motor speed @ 80 mph = 9,241rpm
Motor speed @ 100 mph = 11,511 rpm (if the governor would let you get there!)

The speed is governed at 80mph, so the fastest you spin is 9,240 RPM - well within the motor's 10k spec. These are AC brushless motors that require no maintenance. If you worry about "more wear on everything" please understand that the motor is rated for over 1 million miles of use with no maintenance. With no brushes, there's not much to wear. The output shaft sits in a bearing race that is designed for the load and RPM. That's about the only wear part. There is no transmission. No trans fluid. No trans weight or complication. I think that's a fair trade-off for having just one "gear."

All production EVs only had one "gear." What's astonishing is being able to smoke the tires from a stand-still, at zero RPM - with no clutch mind you - in the same gear that'll go 80 mph on the freeway. In the many millions of production EV miles that have been driven, I've not heard of a single motor "wearing out." Tires are another story.

The Tesla has a two-speed trans (which has given them no small number of headaches - the production units they first tired to use could not handle the torque!) - the main reason is so the car won't top out before the quarter mile. The X1 that I drove (0-100-0 in eleven seconds) only has one gear, and it tops out at about 112 mph - well before the quarter mile. I don't bring these cars up to compare to Honda Accords. I bring them up just to demonstrate different EV transmissions that I'm familiar with. For normal driving, it is obvious that an EV does not need more than a single gear. To smoke the competition at the track, there needs to be a way to lower torque and gain effective HP at the high end.

None of these cars have ever had a gear for reverse either of course. In fact there is no way to decouple from the gearing. You simply spin the electric motor backwards to go backwards. Neutral just means that you don't apply power or braking force - the gears are still spinning - just with no pressure on them. With no transmission, the acceleration and decel are butter smooth. Never a jerk to the next gear - and you are always in the "right" gear. No efficiency losses assocated with transmissions either.
 
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Darell

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To be able to row through your own gears is half the fun, but maybe that's just me.

I agree. It is fun. And so is all the noise and vibration. Driving EV is just another kind of fun. Like the difference between power boating and sailing. Waterskiing and surfing. Driving an EV feels like the acceleration you get when a plane takes off, or a roller coaster accelerates. You feel like you're in a space ship the first few times. Then that becomes "normal" and everything else feels a bit odd.
 

radellaf

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Most of my friends find that driving to the gym to ride the staionary bike is more "convenient" as well.[/QUOTE]

With the weather around here, it'd be more than just convenient, for exercise.

For work or even just to ride to the cafe, though, I'd have to shower off and carry extra clothes after every trip.

Sometimes cargo volume is a problem. And on those days, I actually drive a car. The other 95% of the time, I'm just moving me, and possible a back-pack-full of stuff.

<shrug> If it works for you, it works...

If I were riding around a college in San Jose, then I'd be doing it too. Short trips, one backpack, and beautiful weather most all of the time.
 

Darell

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<shrug> If it works for you, it works...

If I were riding around a college in San Jose, then I'd be doing it too. Short trips, one backpack, and beautiful weather most all of the time.

The weather is just one of the reasons that I choose to live in CA. As for "short trips" - my regular commute is 23 miles each way.

Because of the last hundred years of amazingly cheap energy, and about as many years of apathy toward environmental damage, we're quite addicted to our powered, personal transportation. The question going forward isn't how comfortable we wish to remain with our transportation - but what can we actually sustain. I don't think anybody can logically argue that we can sustain what we're doing today.
 

Steve K

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I love the idea, but the reality of arriving at my destination either frozen or sweating, and having so little cargo space, is just no good. Gave up motorcycling for the same reason (and found out most do it for sport, not transport).

As a bike commuter, I do symathize.
As for the freezing or sweating, I haven't experienced any risk of freezing. I've found clothes that work well down to 5F or so.

As for sweating, this is an issue in many cases. I would argue that it's as much a societal issue as anything else, but that doesn't solve the immediate problem. I'm fortunate that I can ride to work without getting very warm, and I'm free to get as sweaty as I want on the way home. I'm in central Illinois, and it's much less humid than when I lived in St. Louis. I'll just guess that N.C. is similar to St. Louis?

regards,
Steve K.
 

TorchBoy

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If you were paying for electricity to go 25 miles how much would that be at say $.10 kw or even $.20 a kw?
Units and capitalisation wonky: $0.10/kWh or $0.20/kWh.

Edit: How many posts can you guys get in while I pop outside for a minute to sniff real flowers? I'm sure no one had replied to that when I loaded the page.
 
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Darell

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Sorry Darrell, don't understand this bit. What is "still spinning"?

Think of this as a regular car that is always in gear - no clutch, no way to shift into Neutral. As long as the motor is turning, the gears will be turning (spinning) as well. In a regular car, you MUST be able to decouple the engine from the drivetrain by using Neutral. There's no other way to come to a stop without stalling the engine. This is not needed in an EV. When the gears are stopped (not spinning), the motor can be stopped as well. There is no reason to decouple the motor from the gear box, so it is never decoupled. When the gears are spinning, so is the motor. Spinning just means going around and around.

Did I cover it? Not really sure where I lost you.
 

Darell

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Edit: How many posts can you guys get in while I pop outside for a minute to sniff real flowers? I'm sure no one had replied to that when I loaded the page.

Happens to me often. If you leave a page up and don't do a refresh, sometimes the rest of the crowd can be two pages ahead of you before you get your post in!
 

TorchBoy

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Wait, no transmission? so it's just one gear?
I mentioned that in a rather sarcastic earlier post.

Darell, looking at the simplicity of that pic I have to wonder why it isn't done more often. How much does a motor cost, how much for various battery chemistries (moldyoldy mentioned $1k per kWh Li-ion), and how much heavier is it to get a decent range? They should have great handling with all that weight down low.
 

Julian Holtz

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Hi Darell,

I just had a look at your EV page. I really like it!
I did not know that vehicles like these even existed.
Thank you for this information!

Concerning battery technology, with the help of a friendly guy, I am soon to be one of Germanys first owners of this new size of A123 cells for one of my RC planes:
http://www.rcgroups.com/forums/showthread.php?t=768455

Scrap having to worry about about long recharge times, cell drifting, heavy batterys, less than 100 cycles: These cells are the real deal!
With less than 15 mins of charge time and more than 30 mins flight time, I can be in the air infinitely:grin2:

Great times we are living in.

While these cells might not be the top performers concerning energy density, the lack of potential problems makes up for this.
After all, we want fun in our hobby, and not having to care about this and that detail all the time...
 

radellaf

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The weather is just one of the reasons that I choose to live in CA. As for "short trips" - my regular commute is 23 miles each way.

Well, again, my congratulations on your athletic level of fitness. Even if I could physically do that, it would mean I was commuting the better part of five hours a day, which, IMHO, would be nuts.

Because of the last hundred years of amazingly cheap energy, and about as many years of apathy toward environmental damage, we're quite addicted to our powered, personal transportation.

I'm not a fan of the (IMHO) misuse of the word "addiction", but I thoroughly agree with your point.

We have built a society in which I cannot practically function in without something like a car. My work is 15 _miles_ from where I live. The nearest "3rd place" to hang out is 5 _miles_ away.

I'd love to have a more efficient car, but most of us cannot negotiate a city built the way ours are without one.

The question going forward isn't how comfortable we wish to remain with our transportation - but what can we actually sustain.

"Going forward" - good one ;)

Yes, in the future we will be doing things differently, or not doing them at all.
 
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