Continue EV project or not? Need feedback

[liveforphysics]

Liveforphysics,

One thing you have to consider about the difference between the Honda and Toyota motors is that the Toyota motors are higher power density. They achieve this mostly by operating at high speeds. It may be more lossy, but in the automotive industry the costs are beaten down to the lowest possible value. That means driving efficiency as high as it 'practically' can be for the cost. There's a saying about electric motors that you "pay for torque" which is largely true because it requires a certain amount of material (iron, copper, magnets) to achieve a given torque value. From that perspective, using a high speed motor and gearing it down can lead to a lower cost overall solution than direct-driving. Just take a look at direct-drive wind turbines for examples there. It was almost cost effective to avoid potentially shoddy gear boxes and go with direct drive generators until magnet prices went crazy. In my application, I'm getting something like 8x less speed for 8x more torque. From my perspective, I'd rather have a gear box rather than pay for 8 motors running 8x slower.

That being said, if motors could be designed fairly effectively to operate at higher torque levels using a cost-effective process, then less gear reduction would be necessary (only a single stage), or possibly the gear box could be removed entirely. This is largely hypothetical, because if it was that easy, then it would be an existing product. The closest we have to that is the bike hub motors with 20+ pole designs where the extra magnetic material (steel/iron) is lessened by the smaller and more frequent magnetic loops. However, iron losses become a significant issue at the speeds(frequencies) achieved by the 10 pole toyota motors, where eddy currents in the steel cause heat and drag losses. From that perspective, having more than 10 poles doesn't seem to make much sense, at that speed at least. So if the 'electrical speed' (frequency) is limited, then I can see why practically the most cost effective design has evolved to where it is now (considering air gap tolerances and such).

I agree with you completely my friend with respect to paying for motor torque, it's true. It's also true that stacking 8 high RPM motors together on a common shaft and then running them at 1/8th speed can be silly and costly.

The trick is to run motors made to efficiently make torque in the wheel speed range you want. They don't have to be big or heavy, though if you keep with a conventional radial topology and just grow it longer until you're making the torque you want it does end up big and heavy and costly.

If you start with a topology designed from the ground up for low-speed high torque, you can have your cake and eat it too. You can have a small lightweight package that delivers the torque you want, and doesn't add a bunch of new losses.

One of these per wheel is an example. They would fit the size requirements, and eliminate all the additional stages of losses from gearing/oil/diffs etc. Driveshaft to each rear wheel directly, no other stages of loss needed when the motor is designed to produce the force you require at the speed range you want.

http://www.yasamotors.com/products/yasa-750/

I realize those are pricey now, but that isn't a topology inherent drawback (they would be dirt cheap and available if toyota was running them in the Prius or something though). Looking at the Honda efficiency map, I think the Honda IMA motor stages (which are dirt cheap and available) may get you something even higher efficiency than the Yasa (which is >95% for most of it's range already).

 

[liveforphysics]

Back on the topic of the motors that you've got. Have you by chance taken a look at the winding topology to know if they are in delta or wye? It's also quite common to have tooth/magnet patterns have repeating cycles. That means motor's often have places you can cut and re-crimp new taps in windings. If these motors perchance have 4 repeating sections in the motor, it seems you could cut them and combine them in parallel and end up only needing ~160v to make identical performance to the 650v setup. Or... just bring out all 4 sets of phase leads to run from 4 controllers each driving a relatively low current. I have no idea even how these motors are wound, but just throwing the idea out as a potential option if they happen to be configured in a way with repeating tooth/magnet patterns.

 

[MitchJi]

Hi,

As indicated above, this involved two custom projects, a BMS and a drive/controller. Personally, I think the idea of both of these is very cool as a hobbyist and I think (hope) some of you all do as well, but I need to hear this so that I know that if I get both of these custom projects together that someone beyond me could make use of them.

My $0.02.

Close to zero usefulness to the DIY EV community. How many people will attempt to build a 600v pack using RC lipo cells? How many of them can do it safely? How many people will attempt a very complex dual motor/driveline configuration, when they can buy a wrecked Tesla with a huge high quality pack/bms and a powerful motor/controller for $6k-14k? If you want to do it to learn and enjoy yourself and deplete your bank account go for it.

IMO the only way to build an EV that makes any (more than zero) financial sense is to buy a wrecked OEM EV and as a minimum reuse the pack. A junked Leaf, or Volt or Tesla will probably cost less than just the cost of the RC lipo's you are planning to use and the cell quality will be much better (how many batches of lipo cells did you test).

Any information on how to reuse those cells, or packs with BMS's, hopefully with the motors and controllers could be extremely valuable to the DIY EV community. An affordable, high quality EV with good range and much much simpler than 600V packs (and safer) and a dual motor/driveline configuration. A leaf motor will probably have sufficient power for a 911. If you disagree spend $3k-4k more and start with a Tesla .

 

[liveforphysics]

A friend of mine got a Leaf for 5,500 that just needed a new door, glass, fender, hood, and front and rear bumper covers and paint but was otherwise straight and operates well. I think it was under $2500 in parts including new glass and a very cheap paint job. $8,000 and time for a Leaf to commute with is pretty rad.

But EV conversions of awesome handling Porches are cool using any electric drivetrains in any configurations or power transfer topologies. The best part is, building an EV conversion is more about the journey than the destination anyways. The sooner you start turning wrenches and getting it running with some drivetrain, the sooner you will realize what things you want and don't want.

I used to have a chubby over getting a DIY 2spd transmission from a 2 reduction stage tiny RC motor spinning at 10krpm. I played that game, now I don't like the noise or added turning things wasting my power and wearing out. However, I never would have arrived there without the experience and journey through various EV builds.

Just making something work with what you've got is a very high difficulty conversion, and I think it will be an amazing journey.

 

[MitchJi]

Hi Luke,

IMO the only way to build an EV that makes any (more than zero) financial sense is to buy a wrecked OEM EV and as a minimum reuse the pack. A junked Leaf, or Volt or Tesla will probably cost less than just the cost of the RC lipo's you are planning to use and the cell quality will be much better (how many batches of lipo cells did you test).

A friend of mine got a Leaf for 5,500 that just needed a new door, glass, fender, hood, and front and rear bumper covers and paint but was otherwise straight and operates well. I think it was under $2500 in parts including new glass and a very cheap paint job. $8,000 and time for a Leaf to commute with is pretty rad.

You just reinforced my point. You could probably buy a wrecked Leaf with a really bad body (e.g., rolled) but with a good pack, bms, motor and controller for $2k-3k.

As indicated above, this involved two custom projects, a BMS and a drive/controller. Personally, I think the idea of both of these is very cool as a hobbyist and I think (hope) some of you all do as well, but I need to hear this so that I know that if I get both of these custom projects together that someone beyond me could make use of them.

But EV conversions of awesome handling Porches are cool using any electric drivetrains in any configurations or power transfer topologies. The best part is, building an EV conversion is more about the journey than the destination anyways. The sooner you start turning wrenches and getting it running with some drivetrain, the sooner you will realize what things you want and don't want....

Just making something work with what you've got is a very high difficulty conversion, and I think it will be an amazing journey.

I don't disagree with anything you've said, except that I was responding to the question asked by the OP.

 

[Hillhater]

The trick is to run motors made to efficiently make torque in the wheel speed range you want. They don't have to be big or heavy, though if you keep with a conventional radial topology and just grow it longer until you're making the torque you want it does end up big and heavy and costly.

If you start with a topology designed from the ground up for low-speed high torque, you can have your cake and eat it too. You can have a small lightweight package that delivers the torque you want, and doesn't add a bunch of new losses.

One of these per wheel is an example. They would fit the size requirements, and eliminate all the additional stages of losses from gearing/oil/diffs etc. Driveshaft to each rear wheel directly, no other stages of loss needed when the motor is designed to produce the force you require at the speed range you want.

http://www.yasamotors.com/products/yasa-750/

.

There would seem to be several possible wheel motors in the test/pre-production stage, yet none have yet "hit the road" commercially.
Either we are on the cusp of something special for EV's, or likely to be frustrated by the apparent lack of progress !
http://sports.yahoo.com/blogs/motoramic/protean-electric-rolls-towards-making-wheel-electric-motors-170211509.html
http://green.autoblog.com/2013/07/29/evans-electric-unveils-monster-in-wheel-motor-down-under/
http://www.e-traction.eu/products/thewheel/thewheel-sm440

 

[dnmun]

i checked the auction for the lexus Rh400h hybrid. 6-7 total, 3 in california, 1-denver, 1-houston and memphis for the only one i figured could be used for the motors since it had been rolled so it would be impossible for the body shop guys to rebuild it and make money. so that one went to a junkyard so if someone is interested in getting one of the rear motors or any of the electrical parts from it we could likely track it down through coparts and you could by the parts from the junkyard when they part it out.

 

[BigOutrunner]

Dnmun, Thanks for your comments. I suppose I should clarify. I do have a job, and a Ph.D. in electrical engineering. My job is a co-founder for a start-up company developing prototype electric motors. I have my hands full with work and money is not really the issue of concern. It's a question of motivation. The reason I'm inquiring here is to see if anyone else finds what I'm doing valuable enough to want to use it, or a future version of it, for themselves. The controller, powering motors that can be purchased for less than $1K each, represent a package that is significantly less costly than commercial systems from UQM, Solectria, etc. As for the battery management system, i have yet to see an active manager on the market currently that actively balances cells (and increasing the range of an aging pack or a pack with damaged cells).

In short, if it's just me who would use these things, its a whole lot of engineering just to say I did it.

Seems to me your startup is developing prototype electric motors that is clearly not applicable to the automotive space, otherwise you would keep this vehicle as your eventual halo demonstrator car. And maybe you should, rather than seek ES forum member interest to complete it. Man, you are quite lucky! Not too many startup founders have the wherewithal to say that money is not a concern. You are a very rare exception.

 

[halcyon_m]

Dnmun, Thanks for your comments. I suppose I should clarify. I do have a job, and a Ph.D. in electrical engineering. My job is a co-founder for a start-up company developing prototype electric motors. I have my hands full with work and money is not really the issue of concern. It's a question of motivation. The reason I'm inquiring here is to see if anyone else finds what I'm doing valuable enough to want to use it, or a future version of it, for themselves. The controller, powering motors that can be purchased for less than $1K each, represent a package that is significantly less costly than commercial systems from UQM, Solectria, etc. As for the battery management system, i have yet to see an active manager on the market currently that actively balances cells (and increasing the range of an aging pack or a pack with damaged cells).

In short, if it's just me who would use these things, its a whole lot of engineering just to say I did it.

Seems to me your startup is developing prototype electric motors that is clearly not applicable to the automotive space, otherwise you would keep this vehicle as your eventual halo demonstrator car. And maybe you should, rather than seek ES forum member interest to complete it. Man, you are quite lucky! Not too many startup founders have the wherewithal to say that money is not a concern. You are a very rare exception.

To be clear, this is my personal project, whereas my work is separate. Practically speaking though, I'd love to put one of our motors in there, but it's too early for that anyhow. When I say 'money is not an issue', I mean to say that I am not trying to turn my retrofit ideas into a cash-positive company, just trying to see if anyone could use it besides me so that I can personally justify the time spent developing it. Where my activities for my start-up are concerned, we are very capital-conscious.

 

[flathill]

To be clear, this is my personal project, whereas my work is separate. Practically speaking though, I'd love to put one of our motors in there, but it's too early for that anyhow.

So what is the secret sauce? Switched reluctance? Flux switching? Multicoil like Axiflux? Or amorphous metal and multicoil like KLD?

No gearbox here:

 

[liveforphysics]

Does that KLD drivetrain use seperate direct drive motors per wheel and therefore has no stupid differential to waste power and be a potential point of failure? I think I'm seeing 2 batts and 2 controllers and HOPEFULLY 2 non-mechanically tied together direct drive rotor to axle pairs.

I REALLY like that style of drivetrain. As EV's drive systems mature, they will move towards this topology of drivetrain and move away from the whole concept of having power transfer/conversion stages (because any power transfer method can only add losses).

 

[flathill]

"It uses direct drive, with halfshafts supplying the power unit’s motive force to each rear wheel. Two motors, linked by an electronically controlled differential, are paired inside a drum, and master and slave controllers are mounted on top. "

Too bad this is only the "golf cart" proof of concept version. They are working on a double size double speed version.

“We set the motor controller here in the States at half speed,” Mr. Caamano said, referring to restrictions imposed by federal and state governments. “It’s capable of 50 miles per hour.”

" allows for the elimination of other drive system components such as the transmission and differential, which prevents excessive power loss and extra weight. Our ground-up engineering approach makes the vehicle weight and power consumption as low as possible to save on battery cost."

It is also modular expandable like the Honda IMA stack idea

"Using the KLD patented stator block technology, power can be upgraded incrementally by adding stator blocks to the motor. This flexibility allows manufacturers to serve different market segments and offers consumers the ability to upgrade to a more powerful system in the future.

STILL NO HARD DATA SO DON'T GET YOUR HOPES UP, BUT I GUARANTEE INDEPENDENT WHEEL DIRECT DRIVE IS THE FUTURE

 

[liveforphysics]

I GUARANTEE INDEPENDENT WHEEL DIRECT DRIVE IS THE FUTURE

Absolutely agree with you my friend, it is the future, it's over a hundred years old of an idea to make an EV that way, and I don't see it ever being beat for efficiency, durability, or performance in an EV. Thank you for the info, I didn't know KLD was doing drivetrain topology so elegantly already, great to see it! KLD is just a short ride away from where I live, I should stop by and check out that drivetrain in person.

 

[flathill]

Report back

Maybe Zero could license some of their tech. I wonder how they can claim cheapest while using amorphous metal. I know China is making shit tons of amorphous ribbon for their transformers (which the USA utilities won't spec to save money short term), so maybe...

hitachi YASA with cheap ceramic mags:

Or maybe it is a powder not true amorphous metal

looks like cost or iron based amorphous ribbon is way down since I last checked:
"comparable with electrical steel sheet "
http://www.ims.org/wp-content/uploads/2012/10/Session7a_01_Mikami_Hiroyuki_Technologies_to_replace_rare_earth_elements.pdf

amorphous begins to shine for high freq multicoil (each coil runs indie like axiflux) direct drive perm mag motors (high efficiency at partial load)

 

[halcyon_m]

For those interested (and this was not the intent of this post), my company now has a new website up.
http://www.c-motive.com

For this project, the independent drive was simply a matter of building up the power to the correct level, and to that end I utilized the capability of active yaw control. These porsches do like to over-steer and send you in who-knows-what direction, so active yaw would be invaluable assuming I could get it to work.

 

[BigOutrunner]

For those interested (and this was not the intent of this post), my company now has a new website up.
http://www.c-motive.com

Let me be the first to say 'Congratulations halcyon_m!'.
Your startup's technology is impressive.
I am looking forward to seeing its application in the real world soon.

LIkewise, I'm anticipating eagerly the assessment - and indeed the questions that Dave, Lebowski, Luke, and the other sharp gentlemen here will raise after viewing the video. I'm sure the discussion will be quite a learning experience - and that is the best aspect of ES.

Best of luck!

 

[flathill]

For those interested (and this was not the intent of this post), my company now has a new website up.
http://www.c-motive.com

Electrostatics ehh 8) no wonder you are not scared of 650v

Using flexure bearings in combination with air bearings to separate the plates is a very novel approach!
Although I have seen gas bearings used before
http://www-mtl.mit.edu/researchgroups/mems/people/schmidt/conferences/84.FrechetteMEMSJan01.pdf

I dont see much benefit in replacing brushes in commodity motors with capacitive power transfer. Even with the plates tightly stacked you will be lucky to hit 90% and the look at much complication you added vs a bldc motor. It is not like this would be an easier retrofit. Maybe a DC homopolar motor could benefit

I'm much more interested in your "high torque" electrostatic motor. You dont see these much except in "UFO's"

(Nuclear powered vector jets with distributed electrostatic motor propulsion)

I doubt you will get it to work without running in a vacuum
Or using barium titanate ala EESTOR (being used in pulse weapons)

I have seen your IEEE papers on power transfer but not on motors
And one motor patent
http://www.google.com/patents/US20130106317
"C-Motive’s manufacturing partners have asked to remain confidential."
Why the secret

Surprised you made no mention of the godfather on your website
Dr. Trump from MIT
"greater than 99% efficiency at full load"
147 page thesis where he proposes global power grid
Too bad he used a million volts
And tooo bad the military wont let this tech out of the bottle
http://dspace.mit.edu/bitstream/handle/1721.1/32556/05523075.pdf?sequence=1
Trump was given access to all of Tesla's papers when he died
He declared in his report there was nothing that could be used by unfriendly hands
More like nothing to see here as little was released to the public
MIT is spook central

 

[liveforphysics]

Peace and love Flathill my friend. He is a fellow excited
EV builder. I think there will be applications where electrostatics make sense to leverage, and it will happen.

Think positive mate, not every technology is leveraged by misled men to do murders. A few things they miss and end up doing something beneficial.

 

[flathill]

Give me data, or give me death!

harsh realpolitik

The UFO and Tesla talk is just to gets the nuts riled up
But much of it is true
And adds to the fun
Fun because it is true ahhaa
Or noot

I dont expect to see an electrostatic motos in my truck anytime soon
I already explored this road

They are perfect for flywheel energy storage with a vacuum and all
but this one needs air bearings so it wont work in a vacuum
it could still work well for dc homopolar motors to replace liquid brushes

Now back to the topic at hand!
Peace out
Peace in

 

[halcyon_m]

For those interested (and this was not the intent of this post), my company now has a new website up.
http://www.c-motive.com

LIkewise, I'm anticipating eagerly the assessment - and indeed the questions that Dave, Lebowski, Luke, and the other sharp gentlemen here will raise after viewing the video. I'm sure the discussion will be quite a learning experience - and that is the best aspect of ES.

I welcome the review and commentary on the technology. Though I'm sure it's obvious to some, but not plainly obvious, the device in the video (the CPC) is not a motor (torque generating device). I just wanted to point that out before the conversation got confusing.

 

[flathill]

the air bearing does not allow closer stacking per se than a standard motor or rotating coupler
it allows very thin rotating plates to be closely stacked that would otherwise be too flimsy to maintain spacing
the idea is novel
best of luck

you might like this:
Dual Excitation Multiphase Electrostatic Drive

they use a liquid dielectric
" Power per weight ration of this motor is calculated as 230W/kg. This value is *almost* same as that of the most powerful electro-magnetic motor."

http://www.aml.t.u-tokyo.ac.jp/research/es_motor/demed_e.html

linear halbach motors are now hitting 1671W/kg so the *almost* comparison is far off from the present state-of-the-art

In a vacuum nothing can beat an electrostatic motor

 

[liveforphysics]

Flathill- You know his product isn't a motor nor does it try to compete with them.

Think of it as a rotary power feed-through system that has it's own set of advantages and disadvantages, and hence is the right choice for some applications and wrong for others.

It isn't trying to be the the world's most power dense motor or something, nor is it trying to be a UFO drive or operate in space etc.

Just a clever no-contact and uniquely voltage offsetable galvanically isolated tollerant rotating energy transfer system. There is no reason to hate on it or compare it to various totally unrelated motor topologies etc, its just a cool rotating power transfer.

 

[BigOutrunner]

Flathill- You know his product isn't a motor nor does it try to compete with them.

Think of it as a rotary power feed-through system that has it's own set of advantages and disadvantages, and hence is the right choice for some applications and wrong for others.

It isn't trying to be the the world's most power dense motor or something, nor is it trying to be a UFO drive or operate in space etc.

Just a clever no-contact and uniquely voltage offsetable galvanically isolated tollerant rotating energy transfer system. There is no reason to hate on it or compare it to various totally unrelated motor topologies etc, its just a cool rotating power transfer.

Luke - on their website they are showing a 'capacitive machine' that they claim is an ' electrostatic motor as a full replacement for motors and generators'. Presumably using the same method.

 

[flathill]

Flathill- You know his product isn't a motor nor does it try to compete with them.

Think of it as a rotary power feed-through system that has it's own set of advantages and disadvantages, and hence is the right choice for some applications and wrong for others.

It isn't trying to be the the world's most power dense motor or something, nor is it trying to be a UFO drive or operate in space etc.

Just a clever no-contact and uniquely voltage offsetable galvanically isolated tollerant rotating energy transfer system. There is no reason to hate on it or compare it to various totally unrelated motor topologies etc, its just a cool rotating power transfer.

Please read my post closer Luke

why would I mention brushes? I know exactly what rotating capacitive transfer is

"I dont see much benefit in replacing brushes in commodity motors with capacitive power transfer"

note they are also advertising a high torque electrostatic motor

which according to the patent

using the same air bearing and flexure method

which I said is very novel

the air bearing is a great idea

the ufo drive is a joke. but some electric military aircraft do use electrostatic motors.

I provided a link to the trump paper because their patent uses trump motors

and trump was given first shot at telsa papers
because he was an expert
a conspiracy is more fun thou
and will get others to read trumps masterpiece

 

[halcyon_m]

It's true, we do have two products we are currently working on. They both do use fluid bearing concepts and from that perspective are similar.

As for power density, if I didn't think we had a shot at besting the electromagnetic equivalent, I wouldn't be spending my time on it. Thanks for the comments.