GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Juggler on May 23, 2014, 09:59:33 AM
-
I would like to listen to opinions/arguments about how much volts/amps/watts MP III motor can safely handle?
The main idea is to add some speed and acceleration with external controller (removing stock internal MP III controller), which will require adding more volts for speed and more amps for acceleration. Not in peak mode, but in continuous mode.
-
With a Lyen controller and a 48VDC GM battery charged to about 56-57 VDC, my 60 Amp analog meter pegged full scale for several seconds. Which says over 3500 watts is easily attainable. As the speed picked up, the current dropped as one would expect.
TTFN,
Dennis
-
I currently run 2000w continous as the bike is used for steep up hill off roading so the watts always stay high. 54v 35a setting on a 12fet lywn controller. The pie gets warm, but for an hour of continuous 2000w it has not over heat yet.
-
Ho about 72V? My main purpose is to reach higher speeds!
-
With a suitable 72V external controller and battery using heavy duty wires the 26" Magic Pie should be able to reach about 40mph on 72V but the 20" Magic Pie can also achieve the same speed on 120V (https://www.youtube.com/watch?v=rN8YfwFB61o#t=69).
Alan
-
I forgot to say the pie I use has had thicker phase wires put on it. At 72v you will probably melt the standard phase wires.... I guess.
-
Hello.
Mate by phase wires you mean only the wires that connect the phases to the controller or the wounds of the motors are done using a thicker wire?
-
Hi,
I mean the three thickest yellow , green , blue wires that come out of the motor to the controller phase.
The copper wiring inside the motor will be ok.
I do not know how many amps the connectors/plugs will handle on the mp3.
Going up to 40mph on a bicycle is quite frightening, you do not have much time to react to anything that comes your way on a public road.
-
With a suitable 72V external controller and battery using heavy duty wires the 26" Magic Pie should be able to reach about 40mph on 72V but the 20" Magic Pie can also achieve the same speed on 120V (https://www.youtube.com/watch?v=rN8YfwFB61o#t=69).
Alan
What's speed might be reached on 16" MP3 with 60V battery? with 72V battery?
-
If the windings on the stator are the same as the 26" MPIII I would expect the speed relative to the difference in wheel size to be at least 25mph on 72V and 21 mph on 60V.
If the windings are different on the 16" pie (i.e. Delta configuration instead of Star) the speeds should be a lot higher.
The unloaded speed of a motor converted from Star to Delta theoretically increases by around 73%, but the resultant torque produced will be significantly less.
Alan
-
If the windings are different on the 16" pie (i.e. Delta configuration instead of Star)
So, how to know? I think 20" is made to run @25kmh@48V, but I'm not sure about 16"...
-
Hello mate,
My MP III on a 26" (rear) wheel:
- no load (wheel off the ground) ~ 51.2Km/h. Divide maximum speed by 3.6 gives us 14.22 m/s. Now divide that by 2.085m (my wheel circumference) and you get 6.82 RPS ( revolutions per second). Multiply RPS by 60 and you get ~ 411.67 RPM,
- full load 42.6Km/h. That is me+the bike weighing 164kg. So proceed as before you get ~ 340.53 RPM.
Things to consider:
- a front MP III will be nowhere near as efficient as a rear mounted one. By efficient I mean transforming power into forward motion,
- no load speed was measured with battery 40% SoC (40% full), so probably I would get a bit more RPM with full battery,
- full load speed was measured with full battery,
- I have 4.5 BAR tire pressure, for lower pressures there will be more friction, thus some power will be lost there,
- I have road tires (Schwalbe Marathon Dureme II) so if using off-road tires there will be some additional power lost there,
- the full load speed is subjected to wind speed when testing. There was almost no wind when I tested my maximum speed. At max speed about 85% of the power is wasted on wind friction!
- because a smaller wheel size, your full load RPM will be a bit higher ( that is assuming same load bike + rider, same motor config, same controller capabilities (mine is the stock internal controller but is version II as it can provide ~32 Amps at full load during take-off. Version 1 I read it could only deliver about 15 Amps), same battery capacity and discharge rate, same drag coefficient ... and the list goes on...
I know the wheel size is different, but maybe it helps someone out there.
Cheers!
-
front MP III will be nowhere near as efficient as a rear
why?
-
basic physics maybe?
OK, once we agree that more weight is distributed on the rear wheel of a bike on a flat surface we are making progress.... Agreed? The actual weight distribution depends on many factors, bike frame, steering angle, rim sizes, terrain inclination, riding speed and wind speed, just to name a few, but 30% front and 70% rear is commonly used ( excluding children bikes).
Now on a flat surface while giving full throttle in both cases rear mounted and front mounted MP III(using standard internal controller), you will see that while the rear almost never breaks adherence (unless on a wet surface and/or while not perpendicular), the front pie almost always slips and looses power (wearing the tire given enough time and practice :p ). A front pie is useless on a wet surface or while riding uphill. The stepper the angle the useless a front mounted pie becomes.
Enough theory, the fact is that on dry asphalt a front pie can never climb the same hills as a rear pie can, nor it can reach and sustain the same speed.
Anyway I feel that we are getting further away from the subject than we should.
On topic now - how much have you guys pushed your MP III with external controller? If I'm not mistaking I saw somewhere on the forum almost 4000 W ... if I remember correctly...
-
how much have you guys pushed your MP III with external controller? If I'm not mistaking I saw somewhere on the forum almost 4000 W ... if I remember correctly...
I managed almost 4.4kW on a MkI Pie with a modified internal controller:
(http://www.arhservices.co.uk/GoldenMotor/MaxPower.GIF)
The torque was incredible and even allowed me to perform my first ever one handed wheelie, but the poor controller didn't last very long after delivering such a huge amount of power. ;)
As far as I'm aware, the windings on the MPI, MPII and MPIII are all the same and I have yet to see a Magic Pie with cooked windings.
Alan
-
Hi Aliasssss
Aw, Fooey, I'm going to get accused of bullying again, but I must disagree with you about front wheel vs rear wheel drive "efficiency". I must start by saying I am not a fan of front wheel drive, for handling reasons, but I dislike BS even more. My experience with efficiency is as some ratio of input to output. If I am thinking of the wrong meaning, please forgive me. I want you to know that wide open throttle/ hard on the brakes is how I like to drive. I'm a G junkie.
Can we start by agreeing that the Pie series is not really very powerful? My Honda lawnmower make more HP than 4KW.
I have used my 48V 20" MP3 with Lyen controller on front and rear wheel drive trikes. (I'm too old for two wheels anymore) The top speed was the same, as measured by my Garmin, at 25 MPH. One trike weighed 140, the other-200 lbs, but my guess is that the frontal area's were similar though one was wider and the other was taller. So front wheel drive can be just as fast as rear wheel drive. The heavier RWD one didn't accelerate as well as the lighter, front wheel driven one. But it wasn't horrible.
As far as wheel spin goes, I experienced no wheelspin what so ever on either configuration. I drove only on paved city streets, never on dirt or gravel. A fairly steep hill was on one of my common routes, and it slowed me down pretty severely but there was never any slippage. There just isn't enough power in a Pie to have any problem like this on city streets, unless the design is so poor as to enhance the problem, i.e.;having 10 % of the weight on the front wheel would probably let you smoke the front driven tire. And cornering would be a real adventure.....
Clearly if you drive on low friction surfaces, having more weight over the drive wheel improves the coefficient of friction, and lessens the probability of wheel spin. So you can design your vehicle to load the driven wheel appropriately for steady state operation. If you participate in hill climbs, on steep low friction hills, front drive just plain sucks because of weight transfer effects caused by the slope. Rear wheel drive can have problems as well, but they are different effects. Front wheel drive loses traction and the front wheel starts spinning, and you stop climbing the hill. With rear wheel drive, like on my old Bultaco (google it) when the front wheel gets light because of weight transfer on a slope, the bike flips over backwards because all the weight shift to the rear wheel improves the traction it gets, even as the front wheel gets so light that goes over your head. And you stop climbing the hill. You have probably noticed that modern hill climb bikes have incredibly long swing arms, just to keep the center of gravity ahead of the rear wheel. I can personally tell you that losing traction and spinning the wheel is hard on the ego, but having a bike come over and land on your helmet is hard on the helmet.
My problem with front wheel drive is centered on the effects that weight shifts caused by high power has on the vehicle dynamics during normal driving. When the weight is biased to the driven front wheel, and you have lots of power, wheel spin is easy to induce, which reduces the effective acceleration. The wheel spin occurs because the initial acceleration causes the instantaneous weight to shift to the rear wheel. With a driven rear wheel, that same weight shift improves the acceleration, as it increases the instantaneous weight on the drive wheel. When braking (with good brakes, not the crap found on most bikes) the weight shift goes the other way. The effect improves the braking effect on the front wheel, but because the rear wheel becomes less loaded, the rear brake can contribute very little to the overall deceleration without locking up. With the rear wheel driven, the weight tends to be more evenly distributed if not biased to the rear, this makes the rear wheel braking contribute longer before locking up.
And yes, I have had the pleasure of driving some good powerful FWD cars, but would prefer to drive a decent RWD car over a great FWD'r. That isn't physics, that is a personal preference we both seem to have.
I welcome your response.
TTFN,
Dennis
-
As far as I'm aware, the windings on the MPI, MPII and MPIII are all the same
So, if the windings are the same, what are differences between MP1, MP2 and MP3? Only Controller?
As for MP3, how to know what Controller version is installed?
I consider to order the MP3 without an internal controller and put an external one (Kelly's Controller with 100A pick & 50 continuous limits). Does it worth the change?
-
front pie almost always slips and looses power
Exactly! I even consider increasing the battery voltage from 48V to 60V (even probably more) just in order to make my motor run faster. I indeed feel the motor speed "sleeps" on the road... The issue is so that only a front motor might be mounted on my vehicle (Trikke), mounting a rear motor is not possible...
BTW, is there a way to make the motor not slipping on the road? I use a pretty powerful controller, but it seems the motor doesn't consume enough current and as a result it looses its speed on the road. The Controller also has a boost function, but it's used only on starting up the vehicle and never during the ride...
-
My Honda lawnmower make more HP than 4KWA
Could you please provide a link to this motor?
-
...I'm going to get accused of bullying again...
Nobody is accusing you of anything mate, we do like constructive topics ;)
Can we start by agreeing that the Pie series is not really very powerful? My Honda lawnmower make more HP than 4KW.
No we cannot! MP III is powerful enough to be used on bikes that weigh around 80-90 lbs, that is bike+motor+controller+dashboard+battery... If you use an MP III on a trike that weighs alone(no rider) 140 or 200 lbs you will get that under-powered-ish' feeling. Just look at what Bikemad has achieved with his pie - around 4.4Kw, not to say that your lawn mower will probably only go 12mph and wake up the whole neighborhood if not by noise (which is very loud) then by the stinky smell :P
Anyway this is not the place to discuss ICE engines, nor compare them with electric motors... (this is a thing that hybrid car designers have yet to understand ??? )
I have used my 48V 20" MP III with Lyen controller on front and rear wheel drive trikes.
It's not enough to use a controller that can feed the motor enough Amps, you must also have a battery that can sustain that same amount of Amps. There might also be BMS limitation (though probably not the case).
Do you have an idea of the weight distribution on those trikes, because to me they look a bit heavier on the front, at least the one with front traction. If you do have enough weight on the front wheel as so it wont slip under full-throttle you can get away with using a front pie I guess... as long as your front tire is soooo W I D E!
Anyway your comparison is not quite ideal because the 2 trikes are different weights classes. Should the trikes have the same weight you will see that to some extent I will be right about the speed of a rear pie being higher, and it's not just the top speed, the acceleration is impacted even more... Please give additional info about the specs of your Lyen controller and your battery pack e.g. chemistry, capacity, weight, charge and discharge rates... No need to anymore, I saw the youtube video ;)
Dennis I really do love the trike thingy in your avatar picture and I've been trying for days to find a related post with more picture. Maybe you can help me with that because I never seem to dare asking otherwise ... it's beautiful :)
I respect the work you've done and your trikes look awesome! I really like the rear driven one more, but both are great.
Reading the rest of your post I see that you do to some extent think the same about the front vs. rear traction systems, but then again you are so wrong about one thing - it is basic physics that apply here and there, as well as everywhere, just ask around ;)
Maybe Gary from GM Canada can explain a bit for us the feeling he gets on his front driven Cannibal...
(http://www.arhservices.co.uk/GoldenMotorCanada/Cannibal024.jpg)
Cheers guys ;)
-
Hi Aliasssss
A while back I disagreed with somebody and made him cry, so I am a bit sensitive about disagreeing with folks now. My grandkids think it is funny as hell that I'm considered an internet bully.
I was wrong about my lawnmower, it is only 5.2 HP, while 4kw is about six. The fact remains, on a motor vehicle that isnt very much power. I made a mini-bike back in the 60's with one of my 9HP go-kart racing motors, and it couldn't have weighed even 50 lbs. it could pull a wheelie at 40 MPH! That was powerful. A stock MP3 is only about 1.5 HP. That just isn't much power to this old guy.
All my stuff is GM, except the controller. After frying couple of internals, I bought a Lyen, and have had no problems with it. I had a 30 Amp analog current meter on one of my trikes, and it would peg the needle hard when accelerating, so it was probably drawing 40-50 amps. The motor speed was limited by the applied voltage: 25 MPH. FWD or RWD just doesn't affect that. The avatar photo is of one of my favorite toys, the Morgen 3Eman. It started out a flat sheet steel and tube stock. (My "machine shop" consists of a right angle grinder, a drill press, a bunch of hammers and a welder.) It is fast enough that my grandkids are afraid of it:) And it is heavy. I really missed my design goal on that. I love the paint job on it; I had my grandkids and neighborhood kids paint the flames.
Regarding basic physics, I agree with you and don't agree with you. The photo of Gary's bike shows a really cool looking design, which I really like as a visual object. But from an engineering point of view it is designed to produce wheelspin! He has 3 heavy GM battery packs mounted over the rear wheel, the seat is barely ahead of the rear wheel contact patch, so his weight will be mostly on the rear wheel. The frame is stretched and the rake puts the front wheel even farther forward, which makes the rear bias more pronounced. That said, it won't be any slower at top speed than if it was rear wheel drive. But I'll bet he could pull some gorgeous wheelies if he had the motor in the back!
Nice talking to you,
TTFN,
Dennis
-
So, if the windings are the same, what are differences between MP1, MP2 and MP3? Only Controller?
The MPI and MPII use the same basic stator design and the same style of internal controller mounted on a semicircular aluminium heat sink:
(http://www.arhservices.co.uk/GoldenMotor/StandardStator.JPG)
But the MPII (also available as an external controller version) was redesigned to rectify two major problems with the MPI, the offset wheel rim and the poorly aligned spokes caused by the excessive angle between the rim and the spokes:
(http://www.arhservices.co.uk/GoldenMotor/Freewheel.JPG)
(http://www.arhservices.co.uk/GoldenMotor/RearPie.JPG)
Changelog:
1)Max volts accepted increased to 90V (accepts 24V, 36V, 48V and 72V)
2)Controllers are upgraded to programmable controllers of which the controller's parameter settings can be edited using a PC with optional interface cable with USB port.
3)Major spoke pattern upgrade to increase reliability of the spokes (Re: Bikemad spoke diagram)
4)USB-MagicPie II Cable is optional for those want programming features.
5)Motor ring and axle upgrade to relocate the center of the hub, aligning it to the center of the bike frame.
6)16", 18" cast MagicPie, and 24", 26", 700c and 28" spokes MagicPie wheel will be available to adapt most exsting bicycles
(http://goldenmotor.com/SMF/index.php?action=dlattach;topic=1653.0;attach=1739;image)
(http://goldenmotor.com/SMF/index.php?action=dlattach;topic=1653.0;attach=1741;image)
(http://www.arhservices.co.uk/GoldenMotor/Compare.JPG)
The MPII on the left and the MPIII on the right in the above photo both have the same unorthodox spoke pattern but the MPIII has a totally different controller and stator design:
(http://www.arhservices.co.uk/GoldenMotor/MP3StatorLH.JPG)
It also incorporates a cooling fan unit to provide more air flow over the controller:
(http://www.arhservices.co.uk/GoldenMotor/P5041904.JPG)
As for MP3, how to know what Controller version is installed?
The outer face of the early MPIII controllers was completely flat whereas the later controllers have the Golden Motor logo cast into them and are finned to provide a larger surface area for improved cooling:
(https://arhservices.co.uk/GoldenMotorCanada/MP3_OriginalAndUniversalController_zps4a85137f.png)
I consider to order the MP III without an internal controller and put an external one (Kelly's Controller with 100A pick & 50 continuous limits). Does it worth the change?
If you want to use a higher voltage for greater speed or more current for greater torque (you will also need a suitable battery that is capable of delivering higher Amps) then it is definitely worth doing.
You are the only person who knows what speed and power you want from the motor, so you must decide which battery/controller set-up will provide you with the output you are looking for.
Alan
-
What are voltage and current limitations for the MP3 Smart Int Universal Controller? Did GM publish its specifications in some place?
-
In response to ( maybe Gary can contribute to this topic about his Cannibal ) . Gary has already said last year that he would loose traction with the front wheel in wet and muddy conditions . I have the same bike with a Smart Pie front and mid mounted battery and have never had wheel spin unless I induced it to show someone how much power it has at rest . It won't spin with me sitting on it . I don't ride in mud or take my bike out in rain , they don't like it . The Cannibal is not a good example for the previous argument that rear wheel drive is better as there is very little weight on the front wheel . A standard Mountain Bike or even Beach Cruiser has more weight on the front wheel. Also Gary's bike did not come with any brakes in the front where as mine came with a disk brake , but the disk was mounted on the opposite side of the bike as normal and since the MPII that I had at the time could not be made to run in reverse without rewiring the motor I opted for a Smart Pie which could be run in reverse .
-
Hi Rod,
Damn, that sure is a good looking design. I like the way the upper tubing line flows from front to rear. Gary's battery collection over the rear wheel looks cooler, tho. And to be honest, if I was selling EV stuff, I'd want to have a bike that would smoke the front tire:)
Hey, Aliassss, are you saying efficient but meaning effective in your comments about FWD? Look them up.
TTFN,
Dennis