Magic Pie versus Complete Novice (A Long Winded U.K Review)Sexy photos inside!!

[Leslie]

You can add some solder to the shunt on the internal controller.


Just make sure its well soldered and shorten the shunt with solder to the PCB.

[GM Canada]

No its just two single MPies are better, obviously WAY better than a single dual pie.    And no comment on my range abilities?

I can comment on range. Unfortunatly not with any exact numbers though. When I switch from the rear HBS 48v1000 to a rear Magic Pie I noticed I was arriving at work with more juice in the batteries left then I had before. I attribute this to the larger diameter motor with more magnets equals more power on my uphill ride to work. Then when I added the second Magic Pie to the front I had even more power left over. This I hear from others is due to motor effeciencies (including yourself). Two motors equals less work in the lower rpm range when your sucking up the jouice. I may still add a motor to the trailor some day. Alan's recent paint shop edit of my bike with the trailor motorized looks appealing. If I go with a 3rd motor I guess Ill go further yet!

Gary

[Bikemad]

would a 35 amp infineon controller be ok with a 48v 12ah GM battery?  and would it free up more power?

The GM 12Ah batteries are rated for a Max Discharge Current of 35A and 20A Max Continuous, but I think other forum members have opted for the 40Amp version which can also be modified to run on 60 or 72 volt packs if required:



Those fabricated torque washers should be OK as long as the axle nuts are kept nice and tight, but I would strongly recommend you fit a decent torque arm as well, just to play safe.

Alan
 

[MonkeyMagic]

Hey Andrew

Unfortunately you won't really 'unlock' any more power from your GM battery. You may see a performance difference from using the infineon controller.

Also - was going to ask > you mentioned that you were getting NO difference in changing settings? That's a bit odd, hey maybe check you are doing this:

1. Disconnect power cable to motor
2. Plug in USB cable to 8-pin connector
3. Start PI-200 Software
4. Click 'connect' >> Should say 'connect success' on the bottom left of the window
5. Change some settings around like set the regen to 0%. DONT CLICK SAVE YET
5. Click 'get config' >> check if the regen amount went back to where it was. This will tell you it is reading from the wheel.
6. Change your settings - voltage/current settings etc.
7. Click 'store/save' - should say 'load success' on the bottom left of your screen
8. Click 'disconnect' - should say 'disconnect' success

If you are already doing that and you are not seeing any difference, then try setting your constant amps to 2 and your MAX amps to 5 and you should have a pretty sluggish motor... Do that to see if it's working, I think its a bit weird to experience NO difference on changing the settings

Is your regen changing??

[Leslie]

Gary it depends on your weight and riding conditions.  And the main sign of wasted juice is heat and noise and maybe noise thats inaudible.

When you really load an MP you hear it make a swobble sound. Think of the power a speaker uses to make noise, but make that an inefficient speaker, as far as a motor compares to a speaker.

Now we consider heat.  Any energy that is "not" transformed into forward movement is wasted watts, and heat is a symtom that can also create a cause for inefficiency.


Any motor/s dual or not, make heat, and you start losing the efficiency game.

Audible noise is also a sign thatr heat is being generated.  So if in the config one was to try settings that decrease the noise of the motor they will start seeing increases in range and lower watt hour cycles.

That said you can get these amazing range results just using the throttle.  Waste of power can be a choice thing.  Have the power to cut sick or just stroll along not pushing much current any where past the MF radius of the motor coils.

At last is, what motor and setting are best for the riders terrain.

The gearless as I have seen can go incredible distances in the right conditions.  My hills are not exccessive and I have many long flats in out by the cane fields that surround my town.  This is where some may not see how bloody good a 26" or even a 700c wheel with speed restiction can be when it comes to range.

Another MP rider experiences MP sweetnes using the sleek dynamics of a low ride recumbent getting 7.7 WH/km (12.6 wh/mi)  I get at reasonable speeds and with much self control 10WH/'km  16.4 WH/mi.

The dual Pie would be ok in some circumstances efficiency wise.  If it was decrease heat created on hills sure, and the ability to capture more regen would be a blast.

To do the effieciency test, limit your motor speed.  Run regen off a seperate switch at 100% on a slower bike.  Set all your software below what you do max so no shunt is taking a load.  And throttle like a heavy loaded electric train.  Sloooooooowly.  Find a way to use your brakes as little ,or not at all, by looking ahead and plotting a course with use of minimal brakes. Use regen when ever appropriate.

Such strategies could be consdidered conservative and green in concept.  I have a much easier time running the bike off my solar panels being all tight with efficiency.

I guess you get the point.

But Andrew.  

Look at it this way.  Your motor.  Try take it easy on the pack and get it nice and ripe.  Capacity will increase over the next three weeks up to 25% the more you cycle the pack up.

Then set your setting to low but acceptable, just so you notice a decrease in power to show the software is in conrtrol of your current flow,

Go for a good long easy ride, and you be blown out by how far your 12ah LI pack will take you.

Enjoy the bike how it is as you don't need to be the rocket on the forums.  Take the time to build the rest of the bike up for higher performance.

Even a few weeks riding and getting bto know your areas like pot holes in the bike tracks that are killers and stuff.

Test the spokes out with lower power first.

It's great to move up in power if you really need it.  And I think limited at first is a good move by GM.  

[Andrew]

Please don't get me wrong i'm very happy with the PIE. I will try again with  the controller software and try changing regen to test.  I did exactly as in your above instructions apart from maybe not clicking 'disconnect' - I can't remember .  I will try tomorrow after work.

Could I ask what electrical characteristics should take place by lowering the voltage?

[Leslie]

Please don't get me wrong i'm very happy with the PIE. I will try again with  the controller software and try changing regen to test.  I did exactly as in your above instructions apart from maybe not clicking 'disconnect' - I can't remember .  I will try tomorrow after work.

Could I ask what electrical characteristics should take place by lowering the voltage?

There is an old tale, a myth that the 24v setting causes the PWM (pulse width modulation) frequency to change in the controller to compensate for the lower voltage packs. The current could use a boost in a real 24v system..

When current goes to the motor it is chopped up into pulses, on, off, on, off, and this has an advantageous effect of lowering the effect of  resistance.  When you increase throttle the pwm pulses get wider leaving less off state than on and this effects the motor speed.


If you were to use resistive means to limit the motor speed this would use much more power just to go slow as one is using heat to restrict motor speed.

So when you throttle the voltage stays the same and only pulse length controlls the bike speed..

So if chopping the motor power up into pieces lowers the effect of resistance, just maybe, changing the speed of the pulses to faster has the effect of lowering the effect of resistance further for lower volatge systems.

If you were to set 50 amps at 48v, or 50 amps at 24v the lower voltage effects the max current indicated by ohms law.

R= V/I

Max amps = Volts/resistance

The whole bike has resistance from the middle cell positive terminal of your pack all the way through every part to the motor coil and back to the negative terminal of the middle cell of your pack and in between.

If you were to add this resistance up. or easier take your max amps and divide it by the volts and you will finds the resistance.

say 49v @ 50 amps.

49v/50A = .98 ohms.

So if we plug the .098 ohms into a 24v system and use ohms law.

24v/.98 ohms = 24 amps max.

See the higher voltage alone can increase the max current a motor can sink, leaving the 24v systems stuck at 24 amps MAX even set at 50 amps.

The controller needs a way to balance these differences so it attempts to counter act by means of making the Pwm faster on the 24v setting..

Monkey with the 20" wheel would notice more power on take offs you should experience more power up hills at a higher speed.

As this is only a little trick and not the same as decreasing the resistance to the motor the true RMS power of your motor only changes at certain K. K= rpm per volt..

12 fet~18fet (field effect transistor) controllers have a net lower resistance as the fets in parallel widens the current path to the motor and you should see much less loss of energy due to the volts not dropping over the fet near as much during high load times..

The result of using a 12 fet is the motor needs less RPM to draw more more current, lots of phase events on the smaller controller seem to see less voltage slump over the fets when RPM is higher.

So the 24v setting is not the holy grail on a 26" wheel, as Monkey experiences much lower load on take offs and has higher K than the 26" wheel.

[MonkeyMagic]

Hey it's not just me, I've seen a few people comment on this. And Super Gary's wheels are 26/28" ?

I don't think I have as much speed as a bigger wheel... I get 40km/h on flats and 45km/h max downhill dual drive... but nearly 40km/h uphill lol so its aight

[GM Canada]

Hey it's not just me, I've seen a few people comment on this. And Super Gary's wheels are 26/28" ?

I don't think I have as much speed as a bigger wheel... I get 40km/h on flats and 45km/h max downhill dual drive... but nearly 40km/h uphill lol so its aight

Mine are 26 in and I think your going faster then I am! Mine goes 38 pretty steady on the flat. 34-36 uphill and 42-44 downhill

Gary

[Leslie]

Awesome.

I would need to push 1500+ watts continuous to achieve this.  MY magic controller on the 26" wheel has problems with this area of performance..

Andrew sorry for the long post but I have managed to explain the acronyms we commonly use here, even if you don’t understand everything I am saying you will still have the chance to learn the terms and talk us Ebikers use here at GM forums..


If I could with the 6 fet internal controller on a  26" wheel do away with this awesome efficiency I get, I would limit my range to say 40kms, and get almost identical performance as the 20" wheel on hills and take offs for the RMS same power wasted. As long as more heat/noise is not created, nothing else matter, which is not really realistic pursuit.

The 20" will always have more torque but Monkeys dual 20" must cog like hell and the 20" wheel would have lots of problems with obtaining the same range a 26" wheel can achieve.

Battery life.

With the 20" wheel, it uses more power over long distances cycling the pack lower each ride..  

Battery life is effected by a few things, mainly depth of discharge (DOD) and max current drawn vs C rating..

C rating is based on you ah to current draw.  So if you have a 12ah pack and it is rated at 1C it is rated to give 12amps max.  At 2C its rated
 it will safely give 23amps max and so on.

With the 26" wheel, the range is longer per (WH) watt hour.

I may only use 1 thrid of a pack but I may over shoot my C rating by .5C.

So in one hand I am gentle on my pack where it concerns DOD but am aggressive where it concerns C ratings.


At 1C my pack is rated to have a 1000 cycles, cycle life.  At 2C its rated to do 800 cycles.  While at 100% DOD it rated to do 1000 cycle life and at 66% dod its rated to do 3000 cycles.

So you take the 66% dod at 3000 cycles and plug 80% at 2C and ?I get 2400 cycles.  One very long lasting pack.


The GM batt is rated at 2.5C @ 100% dod at 800 cycles. Which is pretty dammed good for a 12ah pack IMO.

Run it at 50% DOD and you will get 2000 cycles.  Run the PIE more efficiently, you get more range per watt and your pack will live longer for the same miles you travel.

Monkets 20" require less C rarting per Newton meter at high load times meter and in this case it he maintains a good pack life too.


Here is a small list of terms and acronyms which some of you already know and some may help you.  We need a GM glossary thread.  I might start one and everyone can add their bits.

Electrical

R= resistance.
I or A  = current
E or V= volts.
W= watts
EM = elecro magnetic
EMF electromagnetic frequency
P= power
Buck converter.= a circuit designed to power an inductor with PWM that can lower volts by raising amps.
Boost conveter.=A circuit designed to power an inductor with PWM that converts amps into a higher volts.
inductance. = easliy explained, The amount of amps that is drawn into an electro magnet (motor) at a set frequency the return result is measured in henrys..
Impedance.  The resistance an inductor place into a circuit all inclusive and is measured in ohms.


Battery talk

DOD= depth of discharge.
SOC= state of charge
AH= amp hour
C ratring= Imax/AH
Internal resistance= battery resistance.
LVC= low volatge cut off.
HVC= high voltage cut off.
Series connected cells= battery cells hooked in a manner that raise the voltage of the pack.
Parallel.  Battery cells hooked in a manner that raise the current and AH rating of the pack.

EG. The GM 48v 12ah pack has 13s 3P cell configuration. and the 36v 16ah pack battery has a cell config of 10s 4p cells.  Yes the 36v pack comes with one cell more than the 48v pack.  <<<< correct me if I am wrong.





Bike electric motor talk.

BLDC motor=- brushless direct current motor.
Stator= coils and coil chassis in motor
former= coil electro magnet iron core
S= slots, former for the count.
P= magnet poles
Eg. the MP has a 63S 46p stator. 63 motor coils (slots) and 46 magnet poles (poles)

winding= copper wound around former
MF= magnetic flux (field area volume)
MD= magnetic density (field saturation)
phase wires= thick wire that lead to motor stator coils.
Hall sensor= small IC's that detect magnet pole position glued into the stator formers.
3 phase and single phase= The method used to power the motor. single phase uses two wire and three phase uses three wires.
Newton meter, Nm = One newton metre is equal to the torque resulting from a force of one newton applied perpendicularly to a moment arm which is one metre long.  Torque!

Controller talk.

Fets =The component that supplies the power to motor.
PWM= pulse width modulation.
Fet driver- small transistor to drive the mosfet.
Shunt= A high current resistor in the miliohm region for most controllers that will only allow a set amount of current through the circuit.  Limits the max power of a controller regardless off software settings  in the amps field..
PCB= printed circuit board.  The MP internal controller electronics components are soldered onto a good sturdy PCB.

Basic Electronic parts.

capacitor= a device that stores high energy fields.  Buffer or filter.
Diode= a device that allows current in one direction and blocks it in the opposite.
Zener diode= a device that works like a diode until a certain voltage is reached the zener breaks down and allows current to pass.
Mosfet.  Metal oxide field effect transistor.  The component that supplies the power to motor.
Resistor= a device that restricts both current and voltage in a circuit by means of creating heat.
Inductor= Wire wound around magnetic material that converts current and voltage into a magnetic field, can convert amps into volts and volts into amps. A motor is an inductor but transforms volts and amps into momentum.
Pot= variable resistor. eg. a volume knob on an old stereo is a resistor pot.
Linear voltage regulator = One of a few types of IC's that burn volts to achieve a set voltage. The Lm317t is a linear regulator.
Linear current regulator= IC based on the voltage regulator but configured to lower voltage output by burning watts when the set current is reached programmed at the adjust leg to read a voltage drop over output R.
PIC= programmable integrated circuit. Allows an engineer to control many processes at the legs of the ic. cleans a lot of the mess up in a PCB and allow one to design something that need not to be altered on a hardware level.

[Leslie]

Ok now get this.

My MP inductance pole on stator.  540 Uh
My HBS inductance pole on stator 840 uh

The cogging is a sign of transinductance crossfading the stator pole.  But at low RPM, this IMO dissipates the transinductance to equal and cancel the cogging effect sum and off the Pie goes like a rocket.

The lack of inductance in the MP at 0 RPM makes the larger wheels slugs off the mark IMO, and truck loads of current for a brief shot woll solve it on the larger wheels.  Not to good for the pouch lifepo's, but after the intial surge the Pie can take advantage of lots of volts and be very conservative on the amps to keep good form.

Monkey.

Id place bets that the smaller wheels you got will kick like a donkey.


I honestly think my MP 26" beast is a different breed of donkey and needs to be approached differently than say a HBS.  We seem to be treating the Pie like a HBS with the controller regimes we are using.

Things like Gary and you finding out the lower volt setting giving more power has got me thinking about looking for something totally different when getting a controller for the MP.

If only GM sold a 12fet version of the magic controller.  Imagine that!  12 fets and a setting at the 24v.  Voltage would be comming out hard of the phase wires.

[Leslie]

Alan!

This explains the mystery -0.82 amps on the CA.  It happens when I accelerate or pull the brakes.


I turn the wheel very slow and inductance goes through the roof.  OMG  

Not like im seeing with the HBS.


It's It' sa

DC inductance motor?


When the transinductance and energy from the motor spinning meets a path to ground RPM turns the stator former into an electromagnet.  

OMG how ingeneeeious is that.

 

Na na muuuch more fun to be has with this MP me thinks.

[MonkeyMagic]

Wow man that is a mouthful of info, ok I am somewhat clearer on this now.
Hmmm... so apart from riding higher, and better range to some degree, what benefit would I have to change to bigger wheels then?

What I am 100% on is cruising along on a pair of phat 20's is pretty bling lol

peace out

[Andrew]

Wow! I think i'll have read through the above 6 posts quite a few times.  It's good to see some of the commonly used acronyms explained as well as BLDC motor parts and components explained. Thanks Les.

i had fun today commuting to and from work. I made the 5 mile journey to work in 13 minutes. it takes me 20 minutes in the car. The kids in school were quite impressed with the bike build.

Anyone know what a good torque setting would be on the pie wheel nuts?

[GM Canada]

Awesome.

I would need to push 1500+ watts continuous to achieve this.  MY magic controller on the 26" wheel has problems with this area of performance..

Andrew sorry for the long post but I have managed to explain the acronyms we commonly use here, even if you don’t understand everything I am saying you will still have the chance to learn the terms and talk us Ebikers use here at GM forums..


If I could with the 6 fet internal controller on a  26" wheel do away with this awesome efficiency I get, I would limit my range to say 40kms, and get almost identical performance as the 20" wheel on hills and take offs for the RMS same power wasted. As long as more heat/noise is not created, nothing else matter, which is not really realistic pursuit.

The 20" will always have more torque but Monkeys dual 20" must cog like hell and the 20" wheel would have lots of problems with obtaining the same range a 26" wheel can achieve.

Battery life.

With the 20" wheel, it uses more power over long distances cycling the pack lower each ride..  

Battery life is effected by a few things, mainly depth of discharge (DOD) and max current drawn vs C rating..

C rating is based on you ah to current draw.  So if you have a 12ah pack and it is rated at 1C it is rated to give 12amps max.  At 2C its rated
 it will safely give 23amps max and so on.

With the 26" wheel, the range is longer per (WH) watt hour.

I may only use 1 thrid of a pack but I may over shoot my C rating by .5C.

So in one hand I am gentle on my pack where it concerns DOD but am aggressive where it concerns C ratings.


At 1C my pack is rated to have a 1000 cycles, cycle life.  At 2C its rated to do 800 cycles.  While at 100% DOD it rated to do 1000 cycle life and at 66% dod its rated to do 3000 cycles.

So you take the 66% dod at 3000 cycles and plug 80% at 2C and ?I get 2400 cycles.  One very long lasting pack.


The GM batt is rated at 2.5C @ 100% dod at 800 cycles. Which is pretty dammed good for a 12ah pack IMO.

Run it at 50% DOD and you will get 2000 cycles.  Run the PIE more efficiently, you get more range per watt and your pack will live longer for the same miles you travel.

Monkets 20" require less C rarting per Newton meter at high load times meter and in this case it he maintains a good pack life too.


Here is a small list of terms and acronyms which some of you already know and some may help you.  We need a GM glossary thread.  I might start one and everyone can add their bits.

Electrical

R= resistance.
I or A  = current
E or V= volts.
W= watts
EM = elecro magnetic
EMF electromagnetic frequency
P= power
Buck converter.= a circuit designed to power an inductor with PWM that can lower volts by raising amps.
Boost conveter.=A circuit designed to power an inductor with PWM that converts amps into a higher volts.
inductance. = easliy explained, The amount of amps that is drawn into an electro magnet (motor) at a set frequency the return result is measured in henrys..
Impedance.  The resistance an inductor place into a circuit all inclusive and is measured in ohms.


Battery talk

DOD= depth of discharge.
SOC= state of charge
AH= amp hour
C ratring= Imax/AH
Internal resistance= battery resistance.
LVC= low volatge cut off.
HVC= high voltage cut off.
Series connected cells= battery cells hooked in a manner that raise the voltage of the pack.
Parallel.  Battery cells hooked in a manner that raise the current and AH rating of the pack.

EG. The GM 48v 12ah pack has 13s 3P cell configuration. and the 36v 16ah pack battery has a cell config of 10s 4p cells.  Yes the 36v pack comes with one cell more than the 48v pack.  <<<< correct me if I am wrong.





Bike electric motor talk.

BLDC motor=- brushless direct current motor.
Stator= coils and coil chassis in motor
former= coil electro magnet iron core
S= slots, former for the count.
P= magnet poles
Eg. the MP has a 63S 46p stator. 63 motor coils (slots) and 46 magnet poles (poles)

winding= copper wound around former
MF= magnetic flux (field area volume)
MD= magnetic density (field saturation)
phase wires= thick wire that lead to motor stator coils.
Hall sensor= small IC's that detect magnet pole position glued into the stator formers.
3 phase and single phase= The method used to power the motor. single phase uses two wire and three phase uses three wires.
Newton meter, Nm = One newton metre is equal to the torque resulting from a force of one newton applied perpendicularly to a moment arm which is one metre long.  Torque!

Controller talk.

Fets =The component that supplies the power to motor.
PWM= pulse width modulation.
Fet driver- small transistor to drive the mosfet.
Shunt= A high current resistor in the miliohm region for most controllers that will only allow a set amount of current through the circuit.  Limits the max power of a controller regardless off software settings  in the amps field..
PCB= printed circuit board.  The MP internal controller electronics components are soldered onto a good sturdy PCB.

Basic Electronic parts.

capacitor= a device that stores high energy fields.  Buffer or filter.
Diode= a device that allows current in one direction and blocks it in the opposite.
Zener diode= a device that works like a diode until a certain voltage is reached the zener breaks down and allows current to pass.
Mosfet.  Metal oxide field effect transistor.  The component that supplies the power to motor.
Resistor= a device that restricts both current and voltage in a circuit by means of creating heat.
Inductor= Wire wound around magnetic material that converts current and voltage into a magnetic field, can convert amps into volts and volts into amps. A motor is an inductor but transforms volts and amps into momentum.
Pot= variable resistor. eg. a volume knob on an old stereo is a resistor pot.
Linear voltage regulator = One of a few types of IC's that burn volts to achieve a set voltage. The Lm317t is a linear regulator.
Linear current regulator= IC based on the voltage regulator but configured to lower voltage output by burning watts when the set current is reached programmed at the adjust leg to read a voltage drop over output R.
PIC= programmable integrated circuit. Allows an engineer to control many processes at the legs of the ic. cleans a lot of the mess up in a PCB and allow one to design something that need not to be altered on a hardware level.

Wow! Nice post Leslie, I think my ears popped about halfway through!

Gary