"peak power" - Trek 4300 20" Magic Pie build.

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"peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Dec 30, 2011 11:25 pm

What's up yall..
Just got the 20" magic pie wheel in... as recommended by Luke and a few others in the pike's peak race thread.

Image

Holy crap, that rim is no joke. Put a 2.3" tire on it and the tire looks narrow on this rim. Very happy about this - Golden Motor hit the nail on the head when they designed this rim!!!

Image

Diameter is about 11in, versus the MXUS / 9C diameter is about 9.5in.
Width is roughly the same.

This thing is and effing monster and takes off like a scalded cat even at 57v( 15S ) / 33a on the stock phase wires with a saggy 5AH of 20C lipo. Almost threw me and a local friend ( Tom Tom on ES ) off the bike when we would hit the throttle too sharply.

This is faster to accelerate on 1800w than my MXUS motor on 4000w.
It's as about as fast to accelerate as my MAC on 4000w, which was in a word, kind of terrifying.

However, she only goes about 20-25mph on 57v nominal, so i think 72v is going to be the minimum required.

More concrete data later on.. but so far... this motor is looking real good.
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by ohzee » Dec 30, 2011 11:37 pm

Damn that thing is sharp. So does a wheel like that always stay true since you cant really adjust ?

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Dec 30, 2011 11:52 pm

The rim is basically a giant chunk of aluminum bolted to where the spokes would normally attach.
It's more like a car or scooter rim than a bike rim, and if it breaks or is warped, you're basically screwed.

I don't worry about that too much though, it's tough as hell, looks tougher than any spoked bike rim! A 2in. wide tire is the minimum that you could ever fit on this rim, so a big fluffy tire should prevent any serious aluminum fatigue, unless they are using some real junk for aluminum.

I love the rim, i see how it could essentially act as a big heatsink for the motor.
Those shiny 'petals' you see on the case of the hub motor are also extruded a little.

This seems to be a hell of a sleeper motor. I'm surprised that these aren't more commonly used! i'll do more testing tomorrow..
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by iovaykind » Jan 01, 2012 12:02 am

Subscribed. Want to see what kind of sustainable power this motor can take, and at what speeds it will do continuously before overheating.

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by Idontwanttopedal » Jan 01, 2012 5:17 am

Every time I look up magic pie motors I only find hub with inbuilt controllers

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by o00scorpion00o » Jan 01, 2012 6:50 pm

I'm looking forward to the Pikes Peak test!!!

Are you going to leave the 26" wheel on the front ? Can't wait for pics.

people really underestimate how good the pie actually is.

True you do have to put voltage into it, sometimes I think a faster wind would be nice, it would still have plenty of torque!

Don't drill the covers yet, see how you get on maybe!

In the 26" wheel my speed on the steepest part of the mountain 16% was about 13 mph on 16S LiPo, bogging down generated a lot of heat. I forget the controller settings, but it was pulling 3500 watts, so from what I've learned here the 20" will have better torque and might actually get up faster?

It will be interesting to find out how you get on with different voltages, but I think I'm learning that more voltage is better than more current.
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by Alan B » Jan 01, 2012 7:01 pm

Looks good. If you put one in the front wheel also that would be something. Ground clearance problems likely though.

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Jan 01, 2012 7:36 pm

Thanks for your kind words folks :)

OK, so i took the bike out today on 72V / 56A finally..





It's really hard to show how fast this motor is on video. You really have to ease into the throttle or it'll throw you backwards.
I will get more video later on, with a spedometer and all that stuffs. :)

After a few runs around the block, the motor had not even warmed up. I couldn't tell if it was any hotter than the outside air. Couldn't believe it. The MAC and MXUS would have been really hot after that.

I do agree with scorpion... this is a very unappreciated motor, and i'm surprised it hasn't got more air time here on ES. 4000w and it feels like it can take more speed :shock:
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by Alan B » Jan 01, 2012 8:00 pm

Have you compared it to these other motors in the same size wheel? Trying to separate motor from wheel size differences.

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by Brentis » Jan 01, 2012 8:00 pm

Looks real nice. :mrgreen:
Might have to snap one of these up before MPIII take over.
What kinda speed you lookin at in the video? 30mph?
What controller?

I want an honest 40mph/64kph on a 20" rear.
What do you think about 24s LiPo, 40mph?
A Hx3540 in a 20" shows over 40mph @88v40amp
Guessing the pie is a bit slower.
Maybe H.V. Lyen controller and try 30s or 36s. :twisted:
I love the thought of not having to deal with spokes/alignment.

Keep us posted.

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by ohzee » Jan 01, 2012 8:12 pm

Damn thanks for sharing that is a pretty sweet looking ride. Can I ask where and how much ?

When looking into the magic pie motors it was hard to figure out a US distributor with a website
that was not a pita to navigate. So I think that may be one reason.

I also made a mental note on Justin's last video where he stated when testing different motor types the magic pie
was to similar to the 9c and the reason he did not carry it. I could have heard that wrong and I also admit at normal
voltage 36/48 that would probably be true , but I can easily see how the motor could more easily shed heat.

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by cwah » Jan 01, 2012 9:02 pm

Hello,

Do you know what would be the bike efficiency at 25-30 mph? 4000W is a lot. Your lipo pack should be depleted in 10 minutes :lol:

What would be the bike speed at 72V 10AH? (or 96V10AH) I was thinking about getting NiCoMn battery but to keep them alive I have to only use around 1C.
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by biohazardman » Jan 01, 2012 9:10 pm

Looks pretty quick but your missing a few parts yet? I know you just gotta make a test run as soon as it's even remotely possible. I did the same but almost hit some unsuspecting police ociffer cuz of it. Have fun and be safe.
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Jan 01, 2012 11:46 pm

Alan B: To be honest, i have not. Just really impressed with the acceleration per watt. I wish i had more motors to test.

Brentis: I'd recommend it if you've got the high voltage this motor wants :)
I'm not sure about the speed, i tried to get a spedometer today but the bike shops out here were closed. Feels like low 30mph figures. I think 40mph would require about 26S but that's just a guess..
I used a 12FET set to about 56A, and 5AH of 20C lipo ( was probably getting 10V of sag )

30S would be a good voltage to get this baby up to low/mid 40mph figures, but we'll see.. maybe it will saturate or bump up against another limit. I need a HV controller too.. my limit is 100V :(

cwah: No idea yet. A cycle analyst will be on order soon since i can't use my turnigy watt meter over 60v..

biohaz: Yup.. you're looking at what i just threw together in a few hours cuz i couldn't wait.. i think i'm going to keep the pedals off, but it definitely needs a rear brake or at least a strong regen.. :lol:
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by jmygann » Jan 02, 2012 1:31 am

Maybe time to trade in my old 20" brushed motor

does it come with a 6 speed cassette ? what is the tooth count on the small sprocket ?
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by jmygann » Jan 02, 2012 2:09 am

neptronix wrote:What's up yall..
Just got the 20" magic pie wheel in... as recommended by Luke and a few others in the pike's peak race thread.
Link to thread ??
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by Toorbough ULL-Zeveigh » Jan 02, 2012 3:16 am

:?:
jmygann wrote:
neptronix wrote:What's up yall..
Just got the 20" magic pie wheel in... as recommended by Luke and a few others in the pike's peak race thread.
Link to thread ??


:arrow: https://endless-sphere.com/forums/vi ... 65#p466034




:?:
iovaykind wrote:Want to see what kind of sustainable power this motor can take, and at what speeds it will do continuously before overheating.
:arrow:
Alan B wrote:Very nice, thanks to Justin et al.

So the Magic Pie has no advantage over the 9C on the dyno. Interesting.
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Jan 02, 2012 3:38 am

One thing i noticed about the ebikes.ca simulator is that they list a 'golden 500w' motor, not specifically the magic pie. Said motor seems to be real similar to a 9C on the dyno..

I believe the standard golden motor hub is being referred to here:

http://www.goldenmotor.ca/shopping/pgm- ... D#MOREINFO

And this is the motor i have:

http://www.goldenmotor.ca/shopping/pgm- ... D#MOREINFO
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by o00scorpion00o » Jan 02, 2012 5:17 am

I think the 9c would be a faster wind but wouldn't have nearly the torque of the Pie, and would probably burn up with the same power a lot faster!

That's looking good Dave, 23S LiPo might get you to 40 with 120% setting maybe more!

That's a lot of voltage and will mean more watts, it's 87.4 volts nominal x 10 ah will be 874 watt hrs. That's twice what a 12 s 10ah pack would be, could you fit that in the bag? That will give you a range of about 12-15 miles, that's not bad for some serious fun, then just back off the throttle and you will easily get 25-30 miles!

I can't wait for batteries with 2-3x capacity, it would change things for sure!

By the way were the pedals hitting the ground?
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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Jan 02, 2012 5:56 am

I think the diameter of the motor really helps it along. 11 inches versus about 9 inches for the MXUS / 9C style hub.. i'm told that this leads to an advantage in torque.

I could fit 8x 6S packs into the bag just fine, that would give me 24S / 10AH just fine..

The crankset i had on it previously ( 165mm ) have about 2-3 inches of ground clearance now, which is a problem waiting to happen.. currently

This build is still coming along for sure, needs regen enabled, a cycle analyst, probably a high voltage capable 18FET, regen enabled + a back brake, handle bars need to be dropped lower for good aero/wheelie prevention.. proper camera mount.. front suspension.. the list goes on..

Expect my other build thread 'Trek 4300 MAC' to be crickets for a while... :)
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by gensem » Jan 02, 2012 8:16 am

Neptronix,

The pie should be 20% stronger than a 9c in the same wheel at the same watts. But you are using a wheel that 30% smaller thats why the pie looks so strong.
I dont have a pie but I do have a MXSUS and a MAC and at 3kw the MXSUS is still gutless but the MAC is very strong.
Justin we really appreciate what you did!

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by Alan B » Jan 02, 2012 9:54 am

Many factors at play here. Pie gains over 9C in diameter but loses in width. How do you arrive at a 20% difference, and is that torque or power? Larger diameter builds back EMF faster so may result in lower RPM.

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by gensem » Jan 02, 2012 10:34 am

This is what goldenmotor says, but its not technical at all...
http://www.goldenmotor.com/magicpie/fea ... icpie.html
Justin we really appreciate what you did!

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by neptronix » Jan 03, 2012 11:30 pm

Oh dude.. this thing is slower than i thought.. it sure feels fast.. but yeah.. it's not :(
Charged the lipos up to 3.8v/cell exactly.. just to get a nice median speed..

Top speed on 10S: 15mph, 18mph on 120% setting.

Top speed on 20S: 27mph, 32mph on 120% setting.

A fully charged 10AH will get me a few more mph.. 76v versus a fully charged 84v makes a difference. 5AH introduces some sag too..

A cycle analyst will be on order so i can measure my amps. Currently, all i've got is a turnigy watt meter. I will get back to you guys on those numbers.

I think an 18FET controller with 4115's, plus 30S will get me into the speed level i need for basically hitting top speeds that will be good on the streets ( ~35mph ).

Or maybe i just need to ditch it, empty my savings, and get the cromotor or something equally crazy :)
My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The wheelie machine: 20" Rear Magic Pie II on a Trek 4300 MTB

"The best time to plant a tree was 20 years ago. The second best time is now."- Chinese Proverb

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Re: "peak power" - Trek 4300 20" Magic Pie build.

Post by jmygann » Jan 04, 2012 1:30 am

so .... what hub motor would be preferable ?
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