# Want to build 800+km EV!need support



## Demitrius (Mar 5, 2014)

Hi Everyone! 
Our team want to build unique EV with range 800+ k of range. So could you please see it and make some comments?
Here is our Project http://igg.me/at/elar
And here is a little info about us and our project http://eng.elcarcustom.com/ !
Like it! share it! copy-paste it! Support it! 

Thank you for any comments and support!


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## Hollie Maea (Dec 9, 2009)

By the time you finish developing the carbon fiber structure and body you need, maybe the batteries will exist


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## Demitrius (Mar 5, 2014)

Thanks!
We made Porsche Cayenne(2300kg!) run 400+km - and it was 4x4 full time, and with all on-board systems and air suspension. Batery pack 91kWh and it was a few years ago. At present time there are more powerful batteries.

This Project http://igg.me/at/elar is much lighter, has more powerful battery pack(100-120kWh) and combined with special developed CVT and recuperation. So it is possible to run over 1000km but only on highway(55 miles per hour, without extreme acceleration). 

Commercial versions will be able to run 300-400 km.


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## palmer_md (Jul 22, 2011)

Any links to the Cayenne build and range test?


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## cpct (May 31, 2012)

800+ km is more than twice the range of existing EVs, you would probably need 200kWh of battery capacity. Aside of the weight associated with that amount of batteries, this is surely not compatible with a price of 25000 USD, right?

You will develop the chassis yourself? Is it going to be based on an existing drivetrain, motor etc?

While I applaud your enthusiasm and ambition, in my opinion, more details are needed to be convinced of the feasibility of your project.


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## Demitrius (Mar 5, 2014)

Yep! You can watch a little video about Porsche in main video from our project link(some test ride). And there are a lot of video in YouTube, including video from our local TV (AVTO plus). Just type "Porsche electro vnukovo" . But video only in Russian language. At present time Porsche Project lives with its owner(and customer) in Barnaul(Russia) and still on the road. 

Here is Porsche EV vs MB CLK http://youtu.be/jDYOyECt-rg

And here is video about customer and his electrocars.
http://youtu.be/A3xQSSI0s7k
He has Leaf, Volt, Tesla S and EV Porsche. In video he says that in city he is able to run more than 300km on Porsche EV. This guy is very serious, he payed in cash for all his cars.


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## Demitrius (Mar 5, 2014)

About 800+ km and 25k USD.
If we will use standard combination of elmotor connected with wheels by 1-speed gear - then we need huge battery pack(180-200kWh).
The cost of that pack is more than 25k. But in the Project we need only 100-130kWh because we have CVT specialy designed for EV. It will allow to run almost twice more than standard solution.
It is like driving V6 3.5 - in city it will burn 15l\100 km, but on highway it is needed only 6l\100 km.
And we have modified for our purpose standard frame of some off-road race car.
Moreover, the Project will be as much easy and light as it is possible. But commercial version will be comfort and heavier.


Price 25k usd it will be price of EV car kit with range about 300-400 km with some comfort functions.


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## dougingraham (Jul 26, 2011)

Demitrius said:


> But in the Project we need only 100-130kWh because we have CVT specialy designed for EV. It will allow to run almost twice more than standard solution.


The implication here is that existing drive trains are less than 50% efficient which is not true. The motor drive trains in your typical EV is in the mid to upper 80% range. If you assume 100 % efficiency on your motor/CVT combo this would take a Tesla at 322 km range up to 402 km.

Electric motors gain little from the addition of a CVT. The efficiency is flat over a pretty broad range of their operation. The couple of percent you would gain by keeping the motor operating at its best efficiency point is going to be lost in the mechanics of the CVT.

For start and stop city driving lowering the mass of the vehicle is the way to increase range. Regenerative braking plays a small part in this but lowering the vehicle mass makes it less effective. Lowering rolling resistance helps everywhere. At highway speeds it is all about aerodynamics. There is no magic motor/gearbox solution that will double range. The best that could be done would be around 10%. Any belief in improvements beyond that is a delusion.

Do I think you can make an 800km range vehicle? Maybe, but not one that will mix well with regular traffic or have comfortable accommodations for even one person. This would be about 8 times better range than my DIY EV and close to twice that of a Tesla.

But I wish you well on the attempt.


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## Yabert (Feb 7, 2010)

Demitrius said:


> But in the Project we need only 100-130kWh because we have CVT specialy designed for EV.


Yeah! They also lost my vote with this one...
Review some physical laws and do your math one more time!


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## tomofreno (Mar 3, 2009)

Demitrius said:


> About 800+ km and 25k USD.
> If we will use standard combination of elmotor connected with wheels by 1-speed gear - then we need huge battery pack(180-200kWh).
> The cost of that pack is more than 25k. But in the Project we need only 100-130kWh because we have CVT specialy designed for EV. It will allow to run almost twice more than standard solution.
> It is like driving V6 3.5 - in city it will burn 15l\100 km, but on highway it is needed only 6l\100 km.
> ...


Most of the work done by the motor in a vehicle is against rolling resistance and drag forces at highway speeds. Drive train losses are small in comparison, so it is difficult to see how you could halve energy/mile by increasing drive train efficiency (neglecting the question of whether a CVT would do that). 

Also, ic engine vehicles have higher energy/mile in the city primarily due to running while sitting at traffic lights, and poorer efficiency during vehicle acceleration compared to steady highway speed. Electric vehicles have higher energy/mile at highway speeds compared to city driving, since they don't run while sitting at traffic lights, and are much more efficient than an ice. 

What batteries are you purchasing for $25k/200kWh = $0.125kWh?


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## lithiumlogic (Aug 24, 2011)

Re: Transmissions

check out this link, they're developing a 3 speed transmission specifically for EVs, should give a modest increase in highway range over single speed EVs geared for acceleration/top speed.

http://www.greencarcongress.com/2014/02/20140219-dsd.html#more


most electric motors develop peak efficiency at 50% of their maximum torque for a given rpm. Since 70mph only needs 30hp on flat ground, which is a quarter of the power output of most EVs, a transmission that runs the motor at half of max power rpm on the motorway could save a few percent compared with one that has the motor near its rpm limit.


800km is 500 miles.

A tesla model S can do 300 at 60mph and 400 at 40mph, so it sounds doable.

Isn't 90% of energy usage on the highway (the only scenario where range is critical) due to overcoming aerodynamic drag?

In that case, don't get too hung up on reducing weight with carbon fibre etc. The weight of the batteries will dwarf the weight of the body anyway in a long range EV.

What matters is

1) Frontal area. Height and Width must be kept as low as is commensurate with passenger comfort.

This means, DO NOT put so many batteries in a central transmission tunnel as to increase the width of the car. The width of the car should be no more than gives adequate elbow room for two people sitting side by side. Now, for the most part, butt girth is less than elbow width*, so you might have a little bit of room for batteries there, but don't go overboard.

This also means, putting batteries under the driver seat , and possibly the footwell, is self defeating if it forces the vehicle to be taller to have adequate headroom.

Length has no effect on the frontal area however, so go ahead and put those batteries in between the front and rear seat rows, or in between the passenger cabin and the front/rear crumple zones.

2) Drag Coefficient

Obviously, the lower the better. EVs have an advantage over ICE vehicles because they don't need all those radiator grilles and air vents and the bottom of the engine bay can be sealed without worrying about flammable liquids collecting down there and making a fire hazard.

Making the vehicle longer actually helps you get closer to the aerodynamic perfect "teardrop" shape. Google the "Illuminati Motor Works Seven" for an example. 

3) Battery Capacity

Obviously the more the better.

In the UK we don't have separate "Urban" and "Combined" economy ratings, just an average "Combined MPG", which is dominated by the urban cycle. 

Car manufacturers strive to maximise the "packaging" of their family cars, in otherwise to squeeze as much passenger room into the shortest vehicle they can, to keep structural weight down and hence combined MPG up.

At lower speeds, weight is everything. Aero drag becomes smaller than rolling resistance , which is proportional to vehicle weight, and losses from start-stop acceleration (entirely governed by weight) dominate.

So these vehicles may be making sacrifices to aero drag to get lower structural weight for a given level of passenger space.


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## lithiumlogic (Aug 24, 2011)

It seems I didn't read the OP properly before starting on my ramble (previous post).

$25000 only buys you about 60kw/h, and he's talking about getting twice the watt/hr/mile rating of a tesla model S, hence the skepticism of the previous posters. Oh and the sketch drawings on the web site of that dune buggy show a vehicle that would have considerably worse watt/hr mile than a model S, with no obvious place to put a large battery pack...

You could make a long range vehicle on the cheap by starting with something like a messershmitt bubble car, stretching and strengthening the body considerably, and putting a large pack behind the seats. One abreast seating plus highly unconventional styling may get you to the watt/hr mile ratings you're looking for. 

Though a four passenger version would be as long as a bus!


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## major (Apr 4, 2008)

lithiumlogic said:


> Re: Transmissions
> <snip>
> most electric motors develop peak efficiency at 50% of their maximum torque for a given rpm. Since 70mph only needs 30hp on flat ground, which is a quarter of the power output of most EVs, a transmission that runs the motor at *half of max power rpm *on the motorway could save a few percent compared with one that has the motor near its rpm limit.


Half of _max power rpm_  I don't know where you came up with that theory, but I know of nothing to support it. Here is a efficiency plot of the motor from the Leaf. 









One could consider _max power rpm_ 2700RPM or pretty much base speed. So your theory says to fashion the gearing to run it at 1350RPM? That takes a good system and makes it worse. Better to run it in the 5-6000RPM range where it probably does with the present direct drive.

Graph from: http://www.electricvehiclewiki.com/?title=Drivetrain&oldid=2733


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## Demitrius (Mar 5, 2014)

Thanks for critical remarks and some suggestions!
Here is some main mistakes.

- 25k USD it is car kit with small scale production with 50-70kWh battery back!(I hope everyone understand the difference between prototype and small scale production. And it is not only the price.)

- Dune buggy - is just "angry" version for off-road. It will not run 1000km(630miles). But the body frame is almost the same. Highway version wil be much more aerodynamic. And don't forget - only 55-60miles per our is needed for breaking 1000km. Air resistance with that speed is not critical.

- electric motors. It could be cheap, it could be expensive and high effective BLDC that costs more than 20k USD. And they have different RPM and efficiency plot.

- The Project is the prototype, so the cost is almost 100k. 

Our Porsche was able to run 400km(250miles) a year before Tesla S was presented. Don't forget - only one(!) electric motor UQM and full time 4x4, conditioning, heater, ESP, ABS, Airbags and e.t.c So if we take this Porsche and just add the same battery pack (91kWh) - it will run more than 800km(500miles). 
When we started Porsche , a lot of people on forums told us - "It is impossible that you project will run more than 100miles. Here is our calculation!". When Porsche beat 400km range - they had no words. Our team spent a lot of years making cars and other projects. So we believe in our experience and calculation. And if you remember, some years ago was some electric car(the prototype, with EV Smart batteries pack!) that was able to run more than 1000km(625miles).

Our new project is much more energy effective, modern batteries, and only front or rear wheel drive, body+frame is very light. Only that parameters will allow to run at least 15-20% more. Our battery pack is also 50% more, so we have more than 400mile of range. And it is all without CVT. If we add CVT (it is not common or some car CVT with big losses, it is also prototype with high efficiency) we can break 800-900 km range(500-600miles). It is that simple but it takes a lot of time and it is not cheap. It is expensive. Very expensive. 
The prototype - 100k USD, 120-130kWh, special CVT, front\rear wheel drive, almost all main parts will be unique. It is need only for taking part in international electric car marathon. 

Almost all of you is able to DIY car with 10-13k USD and range 60-70miles. It is good enough for you and your local drive. But it is not enough for others. I want EV that runs 350-400km. It is possible, and it is not miracle if it will cost 25k USD. All is needed - is a couple prototypes and about a year of hard work. 


Kind regards!


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## major (Apr 4, 2008)

Demitrius said:


> only 55-60miles per our is needed
> ...... so we have more than 400mile of range. And it is all without CVT. If we add CVT (it is not common or some car CVT with big losses, it is also prototype with high efficiency) we can break 800-900 km range(500-600miles). It is that simple ....


So at 55-60mph how does the addition of a CVT increase your range 25 to 50%? Which is down from the 50 to 100% figure in your prior post.


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## tomofreno (Mar 3, 2009)

lithiumlogic said:


> ...Isn't 90% of energy usage on the highway (the only scenario where range is critical) due to overcoming aerodynamic drag?...


 Not for my car, its about 60% at 60 mph and 67% at 70 mph. And weight is important if you want good acceleration.


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## lithiumlogic (Aug 24, 2011)

major said:


> Half of _max power rpm_  I don't know where you came up with that theory, but I know of nothing to support it. Here is a efficiency plot of the motor from the Leaf.



I was interpreting a motor efficiency plot like the one you just showed, except it wasn't a Leaf motor and the plot looked quite different. Maybe because the leaf is quite conservatively tuned, and if the torque didn't decline so fast in the mid rpm range you'd have a high torque area that is less efficient?

Also the leaf is a permanent magnet motor. Might have slightly different characteristics to AC induction motor or BLDC.



major said:


> Not for my car, its about 60% at 60 mph and 67% at 70 mph. And weight is important if you want good acceleration.


I suppose it depends on the aerodynamics of your vehicle and tyres, and how hilly your route is, especially if you don't have regen. Most of what i've seen online gives the impression aerodynamic drag is 75-80% of the picture, which is why i'd want to optimise for aero at the expense of weight, given the choice.

Anyway this project is about highway range not sporty driving characteristics or economical commuting yes?

Is there a way to experimentally determine the proportion of aerodynamic/vs vehicle mass on your vehicle Tom, or are you referring to documentation produced by the OEM of the donor car?

Like driving on a flat stretch of highway empty and with some weights in the passenger footwell and trunk.

It's going to be a b1tch trying to get to runs where the ambient conditions don't shift around, then what if putting a load of stuff in the trunk makes the car ride nose-up and catch more air, does the increased mass mean an increase in the optimal tire inflation pressure etc.


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## major (Apr 4, 2008)

lithiumlogic said:


> and if the torque didn't decline so fast in the mid rpm range you'd have a high torque area that is less efficient?


What?  Just drop it. It is off topic. 



lithiumlogic said:


> Also the leaf is a permanent magnet motor. Might have *slightly different *characteristics to AC induction motor or BLDC.


Yes, slightly different, meaning generally the same. So what is the point? Nevermind, again off topic.

I think we both agree that his CVT magic range is vaporware 

And your second quote is attributed to me and was really from tomo.


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## palmer_md (Jul 22, 2011)

Yep, an 85kWh pack in a model s give 300 miles range at 55-60mph. That is about 482 kilometers. You want to increase the pack to 120kWh, so that in the Tesla would get you 680 kilometers assuming no losses due to the extra weight.

You want to build a car with the same 120kWh pack that can get 50% more range than a Tesla Model S with the same size pack. While it might not be impossible, it is a VERY tall challenge (Almost Impossible).


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## lithiumlogic (Aug 24, 2011)

major said:


> One could consider _max power rpm_ 2700RPM or pretty much base speed. So your theory says to fashion the gearing to run it at 1350RPM? That takes a good system and makes it worse. Better to run it in the 5-6000RPM range where it probably does with the present direct drive.


I'm having to scroll up and down to write this, it's making me dizzy!

The vertical axis is torque, not power.

to my eyeballs - 

2700rpm = 280 NM
5400rpm = 140 NM
8100rpm = 90 NM

So basically, from 0 - 2700rpm, torque is constant but power increases with torque. The limiting factor may well be the amount of field flux the permanent magnets can withstand.

From 2700 to at least 8100 rpm torque decreases with RPM but power remains constant. In fact it looks constant out to nearly 10,000 rpm. Probably because Nissan are playing ultra conservative on battery power for their air cooled LiMnO4 pack (which doesn't like the heat).

The AC50 at 130V makes max power at 4000rpm and has a max rpm of 8000. Does it maintain the same output out to nearly 8000rpm? I can't remember if it does or not, from the top of my head.

Anyway , the leaf.

Let's assume that 9900 RPM is 95mph , which is pretty much top speed.

70mph would be 7200RPM, at which speed the motor can do a max of 110NM.

However, that corresponds to max power, which in the leaf is 110hp. Assuming we only want 30hp, which is what is needed for a constant 70 on a flat road, we are only asking for 30nm from the motor.

On the graph, 7200rpm at 30nm is the borderland between the yellow and the orange 92% efficient.

Now if we used gears to halve the rpm to 3600 and asked for 60 nm instead -



ok we're actually at exactly the same 92% efficiency. 

So you win this one Tom, at least as far the Leaf goes.

One thing i would say is, that motor efficiency really gets crappy below 20NM regardless of RPM, so if you're on a slight downhill stretch or momentarily get a tailwind/draft another vehicle, you would save something being in the higher gear


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## palmer_md (Jul 22, 2011)

Its does not matter what gearbox, the only way to go 1000k is to drive <40kph (25mph).


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## lithiumlogic (Aug 24, 2011)

OK so you're designing a kit-car. Get it.



Demitrius said:


> - electric motors. It could be cheap, it could be expensive and high effective BLDC that costs more than 20k USD. And they have different RPM and efficiency plot.


Brushed DC motors are far cheaper than AC induction motors of the same output, eg. HPEVS AC35x2 $8900 versus Warp9 $2000. Unless you want to take a punt on a different brand AC motor, but that is probably not for most first time builds.

AC offers regen in town but it's probably not such an advantage in this application.

How much do brushless DC cost, nearer brushed DC or are they closer to AC prices?

I wonder if it would be possible to recycle motor heat to heat the cabin. Eg. Take cabin air, pass it through a crud catcher. Pass it over the heastsink of your controller, then pass into the motor. The heated air gets exhausted back into the cabin, the fan speed can be controlled by a thermistor on the motor. This is not going to be possible with a brushed dc motor, since the air coming out of it may contain nasties (ozone from the brushes if there's any arcing, carbon from the brushes etc).

Although if you think that's bad, read up on where they get the pressurized cabin air from in Jetliners. Any oil leaks from the bearings in the first stage compressors, any rubbing from the blade tips on the fan case, and the PAX get a lovely dose of carcinogens. Happy flying.


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## Demitrius (Mar 5, 2014)

Heating temperature is about 60 C, so it is not effective to use it as cabin heater. Good solution is Webasto. 

Here is info about motors we deal with. All are BLDC, liquid coolant, but the price was up to 30k USD. 
http://www.electriccarcustom.com/en/develelopments/16/

Simple calculation.
We have BLDC 0-10000 RPM.Max torque from 0 rpm.
Top Speed 190km\h(118miles per our)
Power 91kWh
Range 400km at 80km\h(50miles per hour)
Avarage RPM at 80km\h is about 4500 rpm.
QUESTION:
1.How far will it be able to go if we use 30% more power(120kWh)?
2.How far will it be able to go if we decrease RPM to 2800 rpm at 80km\h?
3.How far will it be able to go if if we combine 1.+2. ?

Good luck!


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## major (Apr 4, 2008)

Demitrius said:


> 2.How far will it be able to go if we decrease RPM to 2800 rpm at 80km\h?


So do you think that reducing RPM changes the power required to go 80km/h?

And are you just sloppy or do you not know the difference between power and energy?


Demitrius said:


> more power(120kWh)


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## dougingraham (Jul 26, 2011)

Demitrius said:


> QUESTION:
> 1.How far will it be able to go if we use 30% more power(120kWh)?
> 2.How far will it be able to go if we decrease RPM to 2800 rpm at 80km\h?
> 3.How far will it be able to go if if we combine 1.+2. ?
> ...


1) In the best possible case slightly less than 30% more.
2) Almost no difference if you do every thing correctly.
3) Less than 30% more range.

Not much of a test really.


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## palmer_md (Jul 22, 2011)

dougingraham said:


> 1) In the best possible case slightly less than 30% more.
> 2) Almost no difference if you do every thing correctly.
> 3) Less than 30% more range.
> 
> Not much of a test really.


haha. Awesome.


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## Demitrius (Mar 5, 2014)

I just do not know how in English will be short word for "total battery pack energy(or power? or what )". - Here I am talking about total energy which measures in kWh. 
And Yes! But I don't think, I know that if we decrease RPM up to 30-40%(from 4500 to 2700) there will be less power consumption. But power consumption will be decreased not up to 30%, but up to 15-18, may be even 20%(the less RPM the less Voltage we need. P=IxU ). 
1.So we have 30% more kWh --> we had 400km now we have 530km.
2. We have 20% more effective power consuption --> we can afford additional 20% of range.
3. 530km--> 630km.
And it is only if we change battery pack and gear ratio(and wheels diameter)
So You can add to improvements:
1. Much less weight
2. much better aerodynamic
3. only front or rear wheel drive(instead of 4x4 and additional gear)
4. much less power consumers
5. additional flexible solar panels(it won't give additional power but it could be enough for head light, turn lights, GPS)
6. Batteries with higher ability to receive regen power.

And if it will be necessary we will increase 120 to 130-140-150kWh. Our Goal is 800+km. To attract not EV people to EV lovers 

With all that and others improvements we are sure that we can beat 800+ km.


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## major (Apr 4, 2008)

Demitrius said:


> And Yes! But I don't think, I know that if we decrease RPM up to 30-40%(from 4500 to 2700) there will be less power consumption. But power consumption will be decreased not up to 30%, but up to 15-18, may be even 20%(the less RPM the less Voltage we need. P=IxU ).


I can accept difficulty with the language, but not the physics. You are mistaken about your RPM vs power. Refer to the efficiency map in post #13. A reduction from 4500 to 2700RPM for equal power outputs will result in a decrease in motor efficiency therefore an increase in power from the battery and a shorter range.

You're just making this up as you go, aren't you


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## dougingraham (Jul 26, 2011)

Demitrius said:


> But I don't think, I know that if we decrease RPM up to 30-40%(from 4500 to 2700) there will be less power consumption. But power consumption will be decreased not up to 30%, but up to 15-18, may be even 20%(the less RPM the less Voltage we need. P=IxU ).


This is where you are mistaken. Power = Current (I) times Volts (V). Changing the gearing to reduce the RPM will require a lower voltage but the power required to move the vehicle will remain the same. So current will have to go up so that the power remains the same. The efficiency will probably be lower at the lower RPM because the I^2 * R losses will increase. Using your logic if we change the gearing such that the vehicle goes 80kph with the motor turning 1 RPM we would be using almost no power and clearly this isn't true.



Demitrius said:


> 1. Much less weight
> 2. much better aerodynamic
> 3. only front or rear wheel drive(instead of 4x4 and additional gear)
> 4. much less power consumers
> ...


1) If you add batteries you have more mass. But a different and lighter vehicle.
2) Different vehicle I can accept this.
3) The gain will be less than 10%, probably closer to 5%.
4) No idea what you mean by this.
5) Might be good for a little range during the day. The extra mass and drag probably counters the small gain during all driving condition.
6) The batteries currently can accept currents at the same level as they can discharge so nothing new here. Rear wheel drive vehicles usually cant reach these levels due to traction and stability limitations.


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## Arlo (Dec 27, 2009)

major said:


> Half of _max power rpm_  I don't know where you came up with that theory, but I know of nothing to support it. Here is a efficiency plot of the motor from the Leaf.
> 
> 
> 
> ...


Major. I think the torque falls off early because they limit battery current for the low C rating of the Leaf battery. Would you agree?


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## major (Apr 4, 2008)

Arlo said:


> Major. I think the torque falls off early because they limit battery current for the low C rating of the Leaf battery. Would you agree?


Might be. Likely the system design: Motor/controller/battery/vehicle performance requirements. Ever drive a Leaf? Seemed pretty peppy to me through that region


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## Arlo (Dec 27, 2009)

major said:


> Might be. Likely the system design: Motor/controller/battery/vehicle performance requirements. Ever drive a Leaf? Seemed pretty peppy to me through that region


Yeah we drove one but of course they had 22km range left when we got to it... and I have a powertrain out of one to put in my CRX but I need to build a new inverter. Just wondering how hard I can push the motor.

To me it looks like 250-300 hp peak is achievable and reliably.


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## palmer_md (Jul 22, 2011)

Arlo said:


> Yeah we drove one but of course they had 22km range left when we got to it... and I have a powertrain out of one to put in my CRX but I need to build a new inverter. Just wondering how hard I can push the motor.
> 
> To me it looks like 250-300 hp peak is achievable and reliably.



I just checked out some of the links in your signature. You guys aren't related to goalie girl are you?

http://youtu.be/h_KJXDElIWw


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## lithiumlogic (Aug 24, 2011)

major said:


> I can accept difficulty with the language, but not the physics. You are mistaken about your RPM vs power. Refer to the efficiency map in post #13. A reduction from 4500 to 2700RPM for equal power outputs will result in a decrease in motor efficiency therefore an increase in power from the battery and a shorter range.


The original poster appears to be wildly overestimating the gains to be had, nevertheless there are gains.

And let's stop using the power/efficiency graphs for the Leaf motor, which is a completely different type - the OP linked the specs page for the motor he wants to use.










If you want 20kw, to obtain a constant 70mph on a flat road, the best rpm appears to be 1700. This is about halfway between the boundary of the 87.5% efficiency island and the 90% efficiency area. 

Now with a single speed tranny, say our top speed is 100mph at the 8000rpm rev limit. 70mph would put us at 5600 rpm, at which speed you're right on the boundary of the 80% efficiency line for that output.

80% vs 88.75% is a 10.9% improvement. Will a multi speed manual gearbox have more friction than a single speed reduction box? Maybe but i doubt it would consume all of that.

Now you could give your single speed direct drive taller gearing, up to the point where it gets stuck on hills or burns out the motor, but even geared for a 100mph top speed the motor's maximum power is not available below 50mph.


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## lithiumlogic (Aug 24, 2011)

Demitrius said:


> Heating temperature is about 60 C, so it is not effective to use it as cabin heater. Good solution is Webasto.


I don't really get why this is the case.

Ok, it's liquid cooled.

If you pull in large quantities of ambient air at -20C and blow it over the radiator, the air coming off that radiator will still be at -15C.

But if you are recirculating cabin air, then so long as the water temperature is above 20C it will warm the cabin air on each pass.

OK, as someone who lived in a house with ducted air heating system, i'm aware that could just create drafts that make it feel colder even though the thermometer shows the temperature climbing.

I suppose that's because your body is loosing heat faster because of the air current even though the temperature of the air has gone up. Only if the air blowing over you exceeds your body temperature will this factor no longer apply, since the wind current now increases the rate of heat gain and makes the air stream feel hotter.

Obviously you can't recirculate all the time or the windows will steam up, but the level of recirculation is something you could adjust easily enough - old fashioned car ventilation systems have that control. You'd want the air to pass through a ceramic heater element after it's been through the cooling radiator, for the times when it's cold out and you've got the recirculation turned down.

How much of the system's heat rejection does the water cooling take, or does the motor have an internal fan build onto the shaft and also kicks a lot out to the air in engine bay too?


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## Arlo (Dec 27, 2009)

palmer_md said:


> I just checked out some of the links in your signature. You guys aren't related to goalie girl are you?
> 
> http://youtu.be/h_KJXDElIWw


UHM??? How do you think that?


Because I have some you tube videos I might be related to some other person on youtube?


I build fun electric stuff which has nothing to do with stupid people.


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## palmer_md (Jul 22, 2011)

Sorry, It was meant to be a joke, but its hard to come across that way I guess on the internet.


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## tomofreno (Mar 3, 2009)

lithiumlogic said:


> ...I suppose it depends on the aerodynamics of your vehicle and tyres, and how hilly your route is, especially if you don't have regen. Most of what i've seen online gives the impression aerodynamic drag is 75-80% of the picture, which is why i'd want to optimise for aero at the expense of weight, given the choice.
> 
> Anyway this project is about highway range not sporty driving characteristics or economical commuting yes?
> 
> Is there a way to experimentally determine the proportion of aerodynamic/vs vehicle mass on your vehicle Tom, or are you referring to documentation produced by the OEM of the donor car?...


Depends on CdA and weight. I would guess the Tesla S has lower percentage than my car, since it is quite heavy, and fairly low CdA. Cross section of my car is 19.5 ft, determined by grid placed over a photo of the car with a rule on it for scale. Rolling resistance and Cd were determined by best fit to roll down test data: 0.014 rr, 0.32 Cd. Car has regen, but we are talking about highway driving, probably with few hills, so that's irrelevant.


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## major (Apr 4, 2008)

lithiumlogic said:


> The original poster appears to be wildly overestimating the gains to be had, nevertheless there are gains.
> 
> 80% vs 88.75% is a 10.9% improvement. Will a multi speed manual gearbox have more friction than a single speed reduction box? Maybe but i doubt it would consume all of that.


Using the speeds he quoted at that power and your map, it looks like about 4%. So yes, some gain. But not near what he states. And actually the multi-speed gearbox may be desirable on such a vehicle due to the mass with such a large battery. 

A CVT will not allow him to reduce his battery energy by 30 to 50% as he claims. Or as he says in post#7


> because we have CVT specialy designed for EV. It will allow to run almost twice more than standard solution.


 It's not going to happen


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## lithiumlogic (Aug 24, 2011)

tomofreno said:


> Depends on CdA and weight. I would guess the Tesla S has lower percentage than my car, since it is quite heavy, and fairly low CdA. Cross section of my car is 19.5 ft, determined by grid placed over a photo of the car with a rule on it for scale. Rolling resistance and Cd were determined by best fit to roll down test data: 0.014 rr, 0.32 Cd. Car has regen, but we are talking about highway driving, probably with few hills, so that's irrelevant.


http://www.gribble.org/cycling/crr_cda_solver.html

Something like this roll-down test then?



> *Frolling* (Newtons)
> 
> Note that this force is constant, i.e., is independent of speed
> 
> ...


So the rate of deceleration at lower speed corresponds to your RR, and the greater the difference between your deceleration rate at high speed and decel rate at low speed, the worse your CdA?


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## tomofreno (Mar 3, 2009)

lithiumlogic said:


> http://www.gribble.org/cycling/crr_cda_solver.html
> 
> Something like this roll-down test then?
> 
> ...


 Just recorded vehicle speed versus time from 60 mph down to 25 mph with a GPS while coasting, then fit a regression model, with variables CdA and rr to the data, adjusted coeff's of the two variables for best fit. The fit using the spec Cd = 0.32, and a rr value of 0.014 gave the lowest std error. Used an about 1 1/2 mile long dead end, ~level, side road, did it in both directions and took the average.


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## lithiumlogic (Aug 24, 2011)

http://ecomodder.com/forum/tool-aero-rolling-resistance.php

Yeah i just had a look at this. I guessed the weight of your SwiftE at 1000kg and let the tool use the default coefficient of rolling resistance, 0.008. 

It comes up with 75% aero at 60mph, but yeah with 0.014 your numbers make sense.

The site claims 0.005 to 0.01 is representative of LRR tyres on a smooth surface, your evidence suggests they're being a tad optimistic.


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## Demitrius (Mar 5, 2014)

Hi again! 
I am glad to hear so much critical remarks and different opinions! But I didnt hear any new problems which we are didn't calculate.

And I am understand why it seems unreal for you to break 800+km.(some guys from nowhere and talking about range that seems unreachable for the most of DIY cars)

But take a look at other side. If some company, big company(Tesla, GM, Rimac /with Concept One/, e.t.c. ), will say:"We are going to present You an EV, that is able to run 800km per one charge" - will you believe them? By the way -Rimac Concep One is able to run 500km. 
I am sure - you will believe them.

And I didnt told that only CVT will allow to run twice more. And I will not post here all our technical documentation for our project. 
Concerning batteries - everyone(almost) here knows that there is charging current limit for each kind of battery. And it is impossible to use effectively regen current if battery is able to take only 0.1C without damaging. So if you have other type of battery with 1C or 10C for short time without damaging -the situation will be different. 

Thanks again!
Glad to meet such interested and educated people! 
Good luck with all your calculations and your projects!


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## dougingraham (Jul 26, 2011)

Demitrius said:


> And I am understand why it seems unreal for you to break 800+km.(some guys from nowhere and talking about range that seems unreachable for the most of DIY cars)


It is not unreal to break 800+km. A very light, aerodynamic car carrying only a driver and a bunch of batteries can do it today with a huge budget, if they drive slowly enough, then barely. Replacing the Tesla batteries with ones that hold twice the energy would easily do it. With existing batteries and a driver and three passengers, no magic upgrades to drive trains will get you there. A 100% efficient controller, 100% efficient motor, 100% efficient CVT is not enough to do it. The rolling resistance and the air drag alone is too much for the energy storage of the existing available batteries.




Demitrius said:


> But take a look at other side. If some company, big company(Tesla, GM, Rimac /with Concept One/, e.t.c. ), will say:"We are going to present You an EV, that is able to run 800km per one charge" - will you believe them? By the way -Rimac Concep One is able to run 500km.
> I am sure - you will believe them.


Only if they don't make impossible claims.




Demitrius said:


> Concerning batteries - everyone(almost) here knows that there is charging current limit for each kind of battery. And it is impossible to use effectively regen current if battery is able to take only 0.1C without damaging. So if you have other type of battery with 1C or 10C for short time without damaging -the situation will be different.


Yes there are charging current limits. The batteries Tesla uses are about the worst for this and they can only withstand a 2C rate for the duration of a braking event. Fortunately their battery pack is 85kwh and so a 2C rate for them is about 500 amps. The commonly used LiFe prismatic cells are typically specified for a 3C continuous charge rate but they will all handle 6 to 8 C for the duration of a braking event. The RC hobby cells can usually handle 6-10 C continuous charge currents with short term events of 25 - 50 C or more for short periods. I can't think of any commonly used batteries in EV's that have any real problems with charging currents from regen events. To have a problem you would have to have an unusually small pack.

I can't say that you don't have some trick that would make this possible, but I find it terribly unlikely because there is no magic that would allow it to happen other than an increase in energy density of a factor of 2 to 3. And doubling or tripling the size of the battery pack with existing tech adds too much weight and bulk.


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## johnjcbs (Oct 10, 2012)

I don't get ,if it takes 15kw to make my car go 60 MPH down the highway,how is some magical cvt,going to make it use only 7.5 kw.



Is this like the emperor's new clothes?


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## RIPPERTON (Jan 26, 2010)

I seriously doubt the need for an EV that has a range of 800km.
The vast majority of EV's are going to be commuter vehicles that only need a range of 140km because of the cost advantage of having such a small pack and the charging opportunity exists every day or every 50km.
The rareness of a situation where you need 800km range in an EV leaves you with a flawed or at least unlikely business model that completely defeats your development costs because you will have low sales.
Demitrius you are another Elon Musk starting all over again making rich kids toys for the few elite.
Why doesnt someone mass produce a budget commuter EV on the production scale of the Ford Model T with sales in the millions not thousands.


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## lithiumlogic (Aug 24, 2011)

RIPPERTON said:


> I seriously doubt the need for an EV that has a range of 800km.
> The vast majority of EV's are going to be commuter vehicles that only need a range of 140km because of the cost advantage of having such a small pack and the charging opportunity exists every day or every 50km.
> The rareness of a situation where you need 800km range in an EV leaves you with a flawed or at least unlikely business model that completely defeats your development costs because you will have low sales.
> Demitrius you are another Elon Musk starting all over again making rich kids toys for the few elite.
> Why doesnt someone mass produce a budget commuter EV on the production scale of the Ford Model T with sales in the millions not thousands.


There is a gap in the market, at least in terms of vehicles sold in the west, between the 300 mile Teslas and 100 mile, town only Leafs, I3s etc.

A pack twice the size of the Leaf's would cost less than $19,000 and would allow many people to use their EV as their only transport. For the holiday season drive back to visit relatives, you could drive for 2 hours on the motorway, get a fast charge and a coffee and carry on. Obviously for the travelling businessmen of this world, doing hundreds of miles a day, time is money, they need a vehicle that can do 80mph for 5 hours nonstop with only 5 minutes to fill up and pee in a bottle. But in Europe people like that are a minority.

No , i want a 200 mile EV with fast charge capability for the cost of a leaf + extra $8500 for the additional 20kwh of batteries. The Tesla is way more expensive than that, it is a full on luxury vehicle, which is nice if that's the market you're in for .

TBH, I'd be quite happy with something a little more crude than the Leaf, i don't care about touchscreens and leather and retractable doorhandles and bluetooth or 3g and ipod connectivity, i want an affordable highway capable vehicle with "open source" tech, capable of being serviced by anyone who obtains the info freely available online. I think the Chinese may be producing vehicles like this already actually, there's some BYD sedan with 200miles?

Ranges greater than 200 miles aren't strictly necessary. Rather than forcing every motorist to invest in an oversized pack he's only going to use once a year, just have the government install a few fast charge points on our motor way network. Would cost a lot less overall.

Range seems to be a touchy subject on this forum. Whenever someone starts talking about doing a longer-ranged vehicle, a chorus of people chime in saying no,no,no , don't do that it's a waste of money/the car will be too heavy, range of over 80 miles is impossible with current tech, just take your gas car for longer journeys. Over and above what is required to make sure the person has thought it through and is aware of all the issues (eg. that their donor car might have the aerodynamics of a brick, that they may not be taking into account Peukert's factor etc). 

Range is just one of the factors of conversion performance, if someone wants to make something very long ranged and trade off cargo capacity , cost and weight, there is no need to feel threatened by it, your shorter ranged EV is superior on most counts, but if a long range is what that person genuinely needs or wants, it's their time and money surely?


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## major (Apr 4, 2008)

lithiumlogic said:


> Range seems to be a touchy subject on this forum.


Ripperton obviously has an opinion. But I think most of us would love to see him go 800km. The touchy thing is his fairy tale CVT


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## Arlo (Dec 27, 2009)

major said:


> Ripperton obviously has an opinion. But I think most of us would love to see him go 800km. The touchy thing is his fairy tale CVT


I think its a good idea if he has the money as well. IM sure is not a big deal other then paying a lot of money for a big battery.

This will be a good thing for EVs world wide because so many un educated people don't realize there is not really a limit to the range for a ev other then the price of the battery.

One thing to note is we don't need an EV fire because the battery was done wrong.


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## lithiumlogic (Aug 24, 2011)

major said:


> Ripperton obviously has an opinion.


I think people's opinion depends a lot on where they live. Ripperton is in the Land of Oz. Living out there, intercity journeys are obviously some way from being EV practical - imagine if he had family in Perth!

Similarly Jack Rickard used to go on and on about how you don't need range, if you're travelling intercity you take a plane etc. which is an American perspective.

I live in Nottingham and have family in Newcastle. 160 miles distant. 

If you fancy a laugh, go to www.thetrainline.com and get a quote for an adult return ticket between these two cities, starting tomorrow , coming back the day after.

I'll save a bit of bandwidth -

Ticket prices ranged from £130 to £180. There are two trains per hour, and the journey takes about 3 hours because you need to change trains twice (all our rail lines run to London, if you want to travel between two cities that are not London you're seriously going against the grain). You still have to get to and from each train station of course - shall we add another £15 and an hour for the two taxi journeys.  

Other than a long ranged EV, that is the only way to get between the two cities ICE free.

The other thing is that houses and garages are generally smaller over here. Providing accomodation for two vehicles is maybe more problematic than out in the suburban sprawl of the US. And we got that infernal annual roadworthines/emissions inspection to deal with even on an ICE that gets driven twice a year, more expense.


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## RIPPERTON (Jan 26, 2010)

Train......hmmm

would be cool to have drive on carriages that have power points in them so you could recharge on your intercity journey.


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## palmer_md (Jul 22, 2011)

RIPPERTON said:


> Train......hmmm
> 
> would be cool to have drive on carriages that have power points in them so you could recharge on your intercity journey.


or http://www.teslamotors.com/sites/default/files/blog_attachments/hyperloop_alpha3.pdf

hyperloop


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