ES DIY Motor Challenge

[recumpence]

randy you do yourself no favors with this stuff.

this is a thread aimed at diy motor builds. more than a few threads were this would fit , including mine . it would be a good choice for folks that dont have a shop or the time that i have .

unless im wrong and your gonna document your build of one of these and show us the results ? if so start a thread on it like the rest here or you will do your cause more damage than good.

to be posting in this thread about where to buy an off the shelf ebike motor better than anything that can be done yourself then i will join others and begin to believe you are a shill and nothing more.

Agreed.

Just because you can buy a good "X" item, does not mean it is foolish to build your own. I had a few people on Yahoo tell me RC motors are horrible and will have the efficiency of a drill held against a wheel. I went ahead with my design using an RC motor and much good has come from it.

Let the guys tinker and leave them alone. If you have something useful to contribute, great! That is what this thread is for.

Matt

[liveforphysics]

Are any large RC motor's even made that achieve worse performance in any attribute than the converted alternator motors? They have maybe 5-10x the specific power...

It would seem like if you wanted to help guide a motor decision, the RC motors would be well above converted alternator motors.

[spinningmagnets]

Randy, I find the car alternator/PMA conversion interesting, but...it really does belong in a separate thread.

Starting from scratch is just too expensive and too hard for 99.9% of ebikers who wish for something better

Axel was kind enough to send me a rough copy of his DIY 500W RC motor build-instructions. Trust me, it is EASY (though perhaps time-consuming) and VERY cheap. Scalable to whatever power level is desired. I am anxious to see the results of others efforts from this thread. Based on past postings, these folks will certainly provide a selection of clever solutions (and after all, no single design is perfect for all applications).

a ready made package that will work efficiently from 100 watts to 5 Kw and weigh about 5 kg. Besides 3 hall sensors, and controller a complete motor can be purchased for about $200

Low RPM Permanent-Magnet-Motors are not very efficient. Low efficiency equals shorter range per a given battery pack. A $200 Bafang can be used as a 1-kW non-hub, no need to add the halls plus it weighs a lot less than 5-kg/11-lb. It would provide great range from a small battery at a low amp-draw.

Its not just the motor, 3-kW/4-HP at 24V is 125A, at 48V its 62A...which battery and controller would work?

There may be a use for this in a long-tail cargo bike (low-kV, single-stage chain, 2-kW+/3-HP+) so your competition is the Crystalyte 530X hub series. For the "sweet spot" of 500W-1500W I would recommend the alt/PMA conversion is not even close to being competitive.

[John in CR]

Are any large RC motor's even made that achieve worse performance in any attribute than the converted alternator motors? They have maybe 5-10x the specific power...

It would seem like if you wanted to help guide a motor decision, the RC motors would be well above converted alternator motors.

Isn't there a well over 90% efficiency claim somewhere about an altermotor? I remember that being my 1st question, because if true, then it's hard to argue against. Doesn't that kind of current handling potential interest you?

[jscoot]

Enter one in the contest.

I think we will reach 10-20x the torque/weight ratio of that alternator conversion with our DIY designs.

I'm working on a 3/4" thick 10" rotor diameter motor that will a third of the weight.

Good luck with it. Every motor has it's pros and cons. Some things can be changed in commercail parts to make better motors. Starting from scratch is just too expensive and too hard for 99.9% of ebikers who wish for something better.
Stamping out silicon steel lams to be hand wound is minor compared to other options if planing to market a great ebike motor at a great price.. Where on a bike will you mount your pancake?

With only 3/4" thickness, I will mount it anywhere I like on the side of the bike that happens to work out nicely for the intended chain-line to run. It's less of a protrusion than my battery pack takes up on the triangle of the frame, and much less thickness than a cyclone kit.

My motor will have no stamped steel parts in it. DIY the easy way, but with a high materials cost due to ceramic bearings and carbon fiber materials to keep weight under 3Kg.

Are you going to have any back iron or is your design coreless? I always liked the hybrid design with radial and axial flux.

http://www.greenproductdesignanddevelopment.net/component/content/article/5082

[jscoot]

Randy, I find the car alternator/PMA conversion interesting, but...it really does belong in a separate thread.

Starting from scratch is just too expensive and too hard for 99.9% of ebikers who wish for something better

Axel was kind enough to send me a rough copy of his DIY 500W RC motor build-instructions. Trust me, it is EASY (though perhaps time-consuming) and VERY cheap. Scalable to whatever power level is desired. I am anxious to see the results of others efforts from this thread. Based on past postings, these folks will certainly provide a selection of clever solutions (and after all, no single design is perfect for all applications).

a ready made package that will work efficiently from 100 watts to 5 Kw and weigh about 5 kg. Besides 3 hall sensors, and controller a complete motor can be purchased for about $200

Low RPM Permanent-Magnet-Motors are not very efficient. Low efficiency equals shorter range per a given battery pack. A $200 Bafang can be used as a 1-kW non-hub, no need to add the halls plus it weighs a lot less than 5-kg/11-lb. It would provide great range from a small battery at a low amp-draw.

Its not just the motor, 3-kW/4-HP at 24V is 125A, at 48V its 62A...which battery and controller would work?

There may be a use for this in a long-tail cargo bike (low-kV, single-stage chain, 2-kW+/3-HP+) so your competition is the Crystalyte 530X hub series. For the "sweet spot" of 500W-1500W I would recommend the alt/PMA conversion is not even close to being competitive.

To get much torque out of a high RPM rc motor will require power robbing multi reductions.
Lower RPM higher torque motors can be as high as 93% efficient with PM magnets with any size auto alternators. Since the Delco SI-10 is the most popular for obtaining numerous PM rotors available these are the most economical way to go. Even without silicon steel laminations these PM alternator/Motors can have efficiencies up in the 90% efficiency range including a single chain reduction loss and spinning the wheel. Quality magnets and design of the rotor can over come some core losses to give you better efficiency than any motors that you can buy off the shelf that are rated up to 4000 rpm. If you need a better efficiency than 90% overall to the wheel there is still the option of making silicon lams for a up grade. The weight facter of 10 lbs will not be a factor unless you like to pedal without using the motor most of the time.
A smaller custom built alternator/Motor that weighs less that 3 kg just like Miles motor with much better magnets and rotor design should fit the build here. I will post a video after mounting a cam.

I will leave your thread alone.

[enoob]

leaving it alone is your call . not what i ask.

just contribute in a constructive manner. if you see the original poster doing something that has an obvious flaw point out a better direction, help them make THEIR version better, telling folks what you have is just plain better is beside the point. from what i gather youve never tried and rc build so were does you knowelege base that they are inferior come from ? the point of this thread is -open source design of diy motors. if your gonna just bash ideas and say off the shelf drill against the tire would be better (edit from we to) I would rather you hold your tongue.

I have spent considerable time researching this and have come along way from when we first met on another forum. in that forum you treated me with tangible disrespect and so lost mine.

i dont doubt your knowledge , just your ability to share it in a constructive manner. it would be rather easy to earn my respect back, just talk to folks the same way you'd want to be talked to.

respect that fact that we are here and working towards something better. even if you've achieved the holy grail in ebikeing , good for you . help others get there on their own

personally i hope you stick around and share what you know to move ebike's along .

[jscoot]

leaving it alone is your call . not what i ask.

just contribute in a constructive manner. if you see the original poster doing something that has an obvious flaw point out a better direction, help them make THEIR version better, telling folks what you have is just plain better is beside the point. from what i gather youve never tried and rc build so were does you knowelege base that they are inferior come from ? the point of this thread is -open source design of diy motors. if your gonna just bash ideas and say off the shelf drill against the tire would be better we would rather you hold your tongue.

I have spent considerable time researching this and have come along way from when we first met on another forum. in that forum you treated me with tangible disrespect and so lost mine.

i dont doubt your knowledge , just your ability to share it in a constructive manner. it would be rather easy to earn my respect back, just talk to folks the same way you'd want to be talked to.

respect that fact that we are here and working towards something better. even if you've achieved the holy grail in ebikeing , good for you . help others get their on their own

personally i hope you stick around and share what you know to move ebike's along .

I used the first 1400 watt Aveox RC motors with a $1000. 10 to 1 CGI gearbox in 1989 a year before Aveox started production of the first brushless RC motors. The 2 lb motor/gearbox unit was a combo boat and ebike motor that was about 88% efficient using the best gearbox you could buy and the 1st two brushless rc motors sold.

I still have the two RC motorsI baught from David Palumbo.
I have been sharing what I have learned using inexpensive PM Alternators to do a much more efficient job than RC motors in a constructive manner. I am not here to disrespect anyone or anyones project. It apears the other way around but I am already used to armchair wizzards telling me there unknown facts about alternator motors that I know otherwise. Look how long it took for a few people to except Sram Dual Drive hubs for ebike use when they doubted about what I had told them about 10 years ago. Until people learn the facts on their own by building their own alternator motors and testing them on ebikes they will not ever know what is a competive ebike motor at a great price. As long as people keep making improvements on new motor designs for ebikes here surley they will have to prove to many people that the motors do as the builders say they do. Good Luck! lol with a few lightweight batteries and a video is about the best way I could think of besides competitions 1000s of miles away from each other.
As far as your comments go I think it is you who is rather rude. Did I do something to personaly offend you ? Why do I need to earn anything from you. This is today not 10 years ago.

[enoob]

ok randy lets roll.

I used the first 1400 watt Aveox RC motors with a $1000. 10 to 1 CGI gearbox in 1989 a year before Aveox started production of the first brushless RC motors. The 2 lb motor/gearbox unit was a combo boat and ebike motor that was about 88% efficient using the best gearbox you could buy and the 1st two brushless rc motors sold.
I still have the two RC motorsI baught from David Palumbo.

anything since ? or in your opinion has rc tech not evolved since 89 ?

Did I do something to personaly offend you ? Why do I need to earn anything from you. This is today not 10 years ago.

yes you did on another forum directly called me and idiot for asking a question that may have been obvious to you but would have been tremendous help to any NOOB looking at it. which is the point isnt it ? to get new people into this?

IF you want me to listen you need at least some respect. just like you wont listen to me unless you respect me . at least a little

and yes this is today not 10 years ago so ill rephrase . do you have experience with a modern rc ebike . anything less than half a decade old would do.

ooo i should add . i look forward to some video . specially if its you showing us how to put together a 90 percent + efficient altermotor . then sharing the motor so we can recreate your results.
that is how you participate in this challenge from 1000 miles away. just so you know im in a different country more than 1000 miles away from plenty of the folks here.

[enoob]

I am not here to disrespect anyone or anyones project.

i missed that one in my last post. it shows that you have no idea how you come off on paper. im gonna tell you what all the ban's and suspensions from other forums should have told you already .

you appear disrespectful, rude and flat out contemptuous of people working on ebike motors other than yours.

so you know id love to back up my accusation in the above post but you seem to have edited all your posts on that forum leaving only smiley faces. nice touch

And now unless your next post is something wildly unexpected this will be my last post concerning you in any way. the "foe" option is great in these forums and the remarkable thing here is that ive been a member of one forum or another for almost a decade and this will be only the second time i put someone on my foe list AND its the same person.

[jscoot]

I am not here to disrespect anyone or anyones project.

i missed that one in my last post. it shows that you have no idea how you come off on paper. im gonna tell you what all the ban's and suspensions from other forums should have told you already .

you appear disrespectful, rude and flat out contemptuous of people working on ebike motors other than yours.

so you know id love to back up my accusation in the above post but you seem to have edited all your posts on that forum leaving only smiley faces. nice touch

And now unless your next post is something wildly unexpected this will be my last post concerning you in any way. the "foe" option is great in these forums and the remarkable thing here is that ive been a member of one forum or another for almost a decade and this will be only the second time i put someone on my foe list AND its the same person.

You and others have your own opinions and the one I like of yours is the video! if using say, two 22.2 Volt 5000ma 25-C RC lipo packs you know that one can expect the full rated 222 watt hours from that pack set up. Running a heavy 70 lb ebike including batteries on any round trip with some steep hills should average about 18 watt hours per mile with the trip average speed of 16 to 20 mph depending how hard you pedal. A round trip course of 12 miles at full speed with pedaling hard the watt hour and average speed results would be interesting comparing them with the full speed with no pedaling results.
Being more interesting would be to use three batteries together in series for 66.6 volts and 333 watt hours available for a 18 mile round trip at various average speeds with and without pedaling. Shown on videos you can interpret levels of performance with sight and sound for your own evaluations. Everyone will have there own ideas on how to present there project but any are better than non. Just keep moving FORWARD!

[Miles]

Please can we keep this thread for matters related to the Challenge.....? Thanks.

Anyone is welcome to take part.

The rules are simple.

Goal:

- Over 4Nm continuous torque per kg of motor weight.

Rules:

- Less than 3kg in weight.

- No energy input other than that to the motor itself.

- Capable of practical use on an electric bike.


Dyno test is the judge.

[enoob]

) unexpected. cool

That is a line from my current favorite movie ever, Meet The Robinsons "keep moving forward" got it for the kids but for a few reasons it is to me rather special.

jscoot what you lay out as a test is definitely what i would call the real world end of the testing but it would be rather hard to really compare apples to apples in such an environment as one person may be just stronger and peddle better than others, variations in battery packs, wind , incline and traffic plus others im sure im missing at the moment would all make it rather difficult to get a relative comparison.

But i would still love to see a shot of your setup and a vid of it moving you around those beautifull islands. make it real nice and hit maui's beach just north of "BIG" beach , little beach i think its called

[jscoot]

) unexpected. cool

That is a line from my current favorite movie ever, Meet The Robinsons "keep moving forward" got it for the kids but for a few reasons it is to me rather special.

jscoot what you lay out as a test is definitely what i would call the real world end of the testing but it would be rather hard to really compare apples to apples in such an environment as one person may be just stronger and peddle better than others, variations in battery packs, wind , incline and traffic plus others im sure im missing at the moment would all make it rather difficult to get a relative comparison.

But i would still love to see a shot of your setup and a vid of it moving you around those beautifull islands. make it real nice and hit maui's beach just north of "BIG" beach , little beach i think its called

I mentioned results of pedaling and not pedaling videos and at different speeds over a hilly terrain on round trips with watt hour and average speed results on videos. Please tell is how to compare over all performance of a ebike motor/drive system short of running a ebike wheel on a calibrated dyno with many speeds and loads or having racing competitions with limited watt hours on measured round trip races on a course that has a variety of terrain.

What would be your idea in terms of relative comparison of ebike motor/drive system performance?
I am not interested in making travel videos just to show the scenery. How will this "motor challenge" be judged?
If RC motors are used above 4000 rpm to get any efficiency will the mandatory multi reduction units along with the motor need to be judged together as one unit at the wheel under various loads and speeds. Weight and performance of the total drive system at various speeds and loads is a performance consideration that has to be accounted for just as the related costs. By only rating a motor will not give you the overall performance of the drive system in all conditions. Something for many people here to think about. Quietness and reliability has also been overlooked IMO.

[jscoot]

Are any large RC motor's even made that achieve worse performance in any attribute than the converted alternator motors? They have maybe 5-10x the specific power...

It would seem like if you wanted to help guide a motor decision, the RC motors would be well above converted alternator motors.

Power would be meaningless if you don't have the motor torque. How would any RC motor achive Over 4Nm continuous torque per kg of motor weight without a power robbing multi reduction ? The constraints of this challange does not mention any gearboxes to produce the required MOTOR torque from high rpm motors. To make the motor challange meaningfull there must be a rpm contstaint to be able to configure a motor to work well with spicified single reduction ratio limit. Define your "RC motors would be well above converted alternator motors" statement please.

[liveforphysics]

For specific power, even some dirt cheap RC motors are in the 4.6kw/Kg range. This is with a KV of 130, which easily enables the reduction to be accomplished in a single stage reduction. My own bike is an example of this.

Your motor isn't made to direct drive a rear wheel, you must also incur the losses from power transmission to the rear wheel. The drive train loss between a single stage of 4:1 or a single stage of 10:1 is in the fractional percent area. This is way more than compensated by the broad range of >90% efficiency from the RC motor vs the much heavier and lower efficiency alternator motors.

[liveforphysics]

But this contest isn't about specific power. We thought about that, and it would come down to whom ever was willing to spend the money for the greatest ceramic bearing technology, and the windings would be the solid milled bar 1/2 turn type, and the KV numbers would likely hit the 5 digit range. It would end up with motors that have incredible specific power, but minimal practical use for an EV.

This is why our contest is about specific torque. I'm shooting for my motor to have a KV in the 30's. It will be as near to silent as any air cooled motor can be, and it will work great for driving the wheel of a bicycle with a simple single stage reduction.

I assure you we are making motors as practical as any for EV use.


If you can come up with something under 3Kg, it would be great to have you enter. Nothing else drives a point home like winning.

[Miles]

Randy,

I do understand about drive losses, thanks. I've structured the challenge in this way to allow for a wide variety of motor types/sizes, without it getting too complicated. It's a motor challenge thread. Others seem to get the idea, I don't know why you have such a problem with it....

Why are you worrying about the higher speed motors that, according to you, won't be able to generate the specific torque required?

Entering an optimised PMA motor in the Challenge would be the best way to demonstrate your competence.

I'm not going to allow this topic to degenerate into another one of your soapbox threads.... Put up or shut up

[enoob]

Please tell is how to compare over all performance of a ebike motor/drive system short of running a ebike wheel on a calibrated dyno
How will this "motor challenge" be judged?
By only rating a motor will not give you the overall performance of the drive system in all conditions.
Quietness and reliability has also been overlooked IMO.

Have you read this entire thread ?

DYNO testing of the motor . must make specified torque

performance of the drive system is not the contested . despite the wonders of a dual drive setup does every ebike HAVE to run the same drive. ? i may choose to have the winning motor run in a friction drive setup on the back tire with my drill as a backup.

i dont care about quietness, i want loud, and reliability is something that comes with practical use to discover weak points and reworking to make better. was your first version of an altermotor the one we see now ? or was there a magnet issue that got addressed ? i seem to have read something about that.

[bigmoose]

This is a GREAT thread and a GREAT IDEA! Just like the Centennial Challenges the big guys do... all we need is "someone" to pony up a $1,000,000 prize for the winner. **2

I was wondering if the person entering the motor should supply his/her controller of choice with it when it goes in for dyno testing? Perhaps also some standard battery voltages should be identified for the test so the tester/judge has a chance at having the right power supply.

PS: I'll throw in $20 bucks towards the top prize. This should be great fun to watch!

[Thud]

On Topic:

Laser tach finally arived! (slow boat from China has graphic meaning to me now!)
The Dyno patterns are in proccess & I am looking foward to showing it off.

off topic:
Previously, my favorite word to say aloud was: "phenominal" (with the tricky p-h on the front, it just feels good to say it!) but lately I have been evaluating a new word.
The new word on the top of the list is "Dynomometer"
It has an additional sylible & a hard consanent on the end that gives it "phenominal" closure.

Try it, I think you will enjoy it far more than the previous thread drift....
Dynomometer, Dynomometer, Dynomometer,

(20 bucks will get a lot of kudos!!! too generous bigmoose, Thank you Very much)

[bigmoose]

Thanks Thud!

I'll think with you on the dyno if that is OK? What max torque & max RPM are you going to design to?

[Toorbough ULL-Zeveigh]

Dy-No-Mo-MOMETER!!

JimmieWalker2.jpg (9.01 KiB) Viewed 786 times

[jscoot]

John,

Like I said, larger motors do have an advantage. That's the reason for the 3kg limit. This is the non-hub motor forum

0.5kg to 3kg should be the range that most people want to work within?

A important aspect of having a 5 kg limit would be to enable people to take advantage of reasonable priced high quality magnets, rotors, stators, and housing with a rather large selection to configure a optimal kv and efficiency for a project that most anyone can get involved with to make a powerful bike motor that will progress to the most economical and easiest way to get there high performance ebike on the road. This type of building block system can be tweaked in many ways including stamped silicon laminations and custom thin multi wire stator windings to reduce end turns and have more copper on the stator. Several rotor and magnet arrangements are available for less than it would cost to just to purchase the magnets on your own. If you are thinking of how to get the most efficient bang for the buck the easiest way with tested reliability, this is defiantly it.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=300381762269&Category=121837&_trkparms=algo%3DLVI%26its%3DI%26otn%3D2

[amberwolf]

At 5Kg I could just use my brushed PMDC 4-pole wheelchair motor, which thru the gearbox (an additional 3 or 4 kg) has enough torque to rip itself off my bike, destroy chains, and yank wheels out of dropouts.

3Kg makes that kind of challenge a lot tougher, *and* it gives back 4.4 pounds that one can use for batteries, cargo, or stronger bike frames.


FWIW, I could probably lighten up an F&P BLDC motor to fit in 5KG, but I don't know what kind of torque it would have. 3Kg is more interesting--there's no way I could cut that much weight off of it so it means trying to think of something even more efficient.

More efficient means better use of the very limited power we can carry, and can mean having to carry less of it to do the same work. So I'm all for a lower limit to this challenge, as it makes for more usable results.