Mid drive vs Hub Motor for 10000 watt project
- Thread starter johnnyz
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johnnyz
1 kW
Yup...Did I say I was guessing?..lol...Ive done this before...and it is a pain in the butt...but its got to be done...shouldnt take too long...I couldnt find any info stating that the controller has self learning with regards to this issue..
johnnyz
1 kW
Well....without calibrating the controller which I cant do because Its snowing outside....this thing will not go faster than 50 kph!..even with the bluetooth settings with overspeed on full...and boost..no difference...the guy in St.thomas says that there is either a board in the motor (This is a QSmotor) or a potentimeter in the throttle...mm....well im gonna change throttles and see....
I did get lucky, and found the right combo on the third try..
I did get lucky, and found the right combo on the third try..
johnnyz
1 kW
Well....another throttle and ..exactly the same results...mmm...sure seems to be going faster than 50 kph...but even if it was the settings in the controller outta make it go faster...mmm....anybody have any ideas? (the last thing I personally want to do is open the motor..lol
By the way..has to be the right hall/phase combo because it is only taking 2 amps to push the motor unladen to 50 KPH
Addendum; When I hooked up the three speed switch, with overspeed on, it went 59 KPH but at only 82 volts (battery is almost dead)..so Im gonna charge it up to 92 or so and see what happens. Could the marginal speed increase be because it is such a high pole count motor?..(or high torque)??
Addendum (2); At 90 Volts, it went a max of 62 KPH..an increase of only 3 KPH???...Maybe this things speedo is off...cant be...Anyone know how I can hook up my CA just as a passive display so I can see the correct speed?
John
By the way..has to be the right hall/phase combo because it is only taking 2 amps to push the motor unladen to 50 KPH
Addendum; When I hooked up the three speed switch, with overspeed on, it went 59 KPH but at only 82 volts (battery is almost dead)..so Im gonna charge it up to 92 or so and see what happens. Could the marginal speed increase be because it is such a high pole count motor?..(or high torque)??
Addendum (2); At 90 Volts, it went a max of 62 KPH..an increase of only 3 KPH???...Maybe this things speedo is off...cant be...Anyone know how I can hook up my CA just as a passive display so I can see the correct speed?
John
e-beach
10 MW
Ok, what I don't understand is how you are getting speed tests done with all the wires hanging out and it is snowing outside?
Are you actually riding the cycle, or just propping up the back wheel and watching her spin?
Anyway the basic rule of thumb with motors is that: The rotational speed of a motor is proportional to the voltage applied.
Voltage won't help with greater torque for going up the hills, you need more amps for that.
If you want to spin that motor faster you probably need to increase the voltage of your battery. Don't burn up your new controller, make sure it can handle a higher voltage if you decided to go that direction.
Also if you go with a higher voltage, make sure you don't overheat your motor.
Are you actually riding the cycle, or just propping up the back wheel and watching her spin?
Anyway the basic rule of thumb with motors is that: The rotational speed of a motor is proportional to the voltage applied.
Voltage won't help with greater torque for going up the hills, you need more amps for that.
If you want to spin that motor faster you probably need to increase the voltage of your battery. Don't burn up your new controller, make sure it can handle a higher voltage if you decided to go that direction.
Also if you go with a higher voltage, make sure you don't overheat your motor.
johnnyz
1 kW
e-beach said:Ok, what I don't understand is how you are getting speed tests done with all the wires hanging out and it is snowing outside?
Are you actually riding the cycle, or just propping up the back wheel and watching her spin?
Anyway the basic rule of thumb with motors is that: The rotational speed of a motor is proportional to the voltage applied.
Voltage won't help with greater torque for going up the hills, you need more amps for that.
If you want to spin that motor faster you probably need to increase the voltage of your battery. Don't burn up your new controller, make sure it can handle a higher voltage if you decided to go that direction.
Also if you go with a higher voltage, make sure you don't overheat your motor.
Yup, just the rear wheel off the ground...the wires hanging out are the testers to get the thing to run in the first place (testing the halls and phase wires)..
I understand that Torque = amps and Speed = volts.
I have a 100 volt battery that for these test is at about 90 volts.
The Controller can handle 100 amps easily and 120 volts (I opened the case and found 6 gauge wires for the + and - and 160 volt caps)
There must be a formula to figure the RPM/Voltage of a 28 pole motor in a 16.3 inch wheel. Something seems amiss...as this bike would do 49 kph with the 72 volt setup (about 85 volts fully charged ) vs 100 volt Lithium (98 volts fully charged) and only 6 kph faster..and then with this controller with the overspeed and only 7 kph faster...I am trying to get my CA working on this thing...so far its on but amps are reading in the negative with load and no speedo....
johnnyz said:
The rpm/V will depend on much more than those few variables. Eg.
How many turns of (what gauge) wire per tooth.
Delta or Y.
Strength of the magnets.
How much laminate in each tooth.
Fill factor.
Other...
johnnyz said:
If, for example, your stator was near to saturation when running at 72V, then upping the voltage to 100 would not increase the no-load rpm proportionally, because the stator would simply not be able to absorb/carry the potential extra magnetic field.
johnnyz
1 kW
Buk___ said:
Well...now that on the face of it, makes sense. I never considered this. In fact I should have..even though QSMotors is a good company with quality products, why make a 72 volt motor with anything more than is what is required...looks like a motor re-wind is in the works..Thanks for the reply!
johnnyz said:
The problem with that is that if they've done a bang up job of sizing their stator teeth, then they will form the saturation limit, not the windings.
At which point your only recourse would be to replace the cores with a much higher permeability. You might gain a little by moving to much thinner laminates -- say 0.2mm if they are currently 0.5mm -- but if they are already 0.35mm or less, then you'd probably lose more than you'd gain, through the extra space taken by the 'tween-laminate insulation.
Beyond that you'd need to look at something like metglas, which is expensive, difficult to work with, and almost impossible to source except in bulk.
johnnyz
1 kW
...Buk___ said:
The problem with this scenario is HOW DO I KNOW?...especially if I take it be re-wound..would the "expert" do this know this?...Alternately I could always buy another Hubmotor from QSmotors and specifiy what I need...anyway you look at it its expensive..
BTW...I hooked up my CAv2 and got everything working including speedo and since this was calibrated for my bike before I replaced the controller, unladened speed is 75 kph with FW and 65 without but since I am running with external shunt the amp values appear way too low..so have to somehow figure this out..
johnnyz
1 kW
Buk___ said:
Thanks...thats my next order of buisness...I will give them the number on this motor and they would know if it can be modified for more performance or another hub motor.
Speaking of changes..
I had to use this huge shunt to get the CAv3 working as I could not open up this controller to solder it to the exisiting shunt. Now the values (amps) are very low and out of whack...here is a pic of the side of the shunt..(300 amp .75 mV)...does anyone know how to adjust the values in the CA so as to get a more accurate amp reading?
johnnyz
1 kW
Ok so after a little reading I took the amp rating (300) and 75mV so....75/300=0.25 mOhm.
Since this is what the CA is reading I am assuming I put this resistance in the CA, but it will not go that low...keeps coming back at .772...
and still the readings on the CA are whacked...(way too low)
John
Since this is what the CA is reading I am assuming I put this resistance in the CA, but it will not go that low...keeps coming back at .772...
and still the readings on the CA are whacked...(way too low)
John
I'm not sure why you have seen such a limited speed increase going from 72 to 100V but I can't see how it's anything inherent to the motor? Magnetic saturation is surely only the result of excessive winding current and nothing to do with voltage. At no-load, the current will be very low and you should be nowhere near any saturation effect.
The only things I can think to suggest are to verify the wheel speed in case there is something weird going on with your speedo. Otherwise, are you possibly bumping up against the eRPM limit for the controller due to the motor being such a high pole count?
The only things I can think to suggest are to verify the wheel speed in case there is something weird going on with your speedo. Otherwise, are you possibly bumping up against the eRPM limit for the controller due to the motor being such a high pole count?
flippy
1 MW
- Joined
- Aug 12, 2015
- Messages
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i have the same issue with my hub motor. 2.5kW 10". i have tried 2 motors from different factories and both are 48v. i went from 48v lead to currently 16S lithium (65v charged) so a easy 15v increase under load and i went from 43km/h to 51 while according to my calculations i should get 55+ easy.
i use a (300A) kelly controller wich is way overspecced for my use but something is causing the motor not getting higher speeds depsite cranking in enough volts to get 60km/h easy.
i use a (300A) kelly controller wich is way overspecced for my use but something is causing the motor not getting higher speeds depsite cranking in enough volts to get 60km/h easy.
johnnyz
1 kW
Punx0r said:
Yeah, obviously Im not that hip with the inner workings of these things but I think the high pole count leads to very diminishing gains relative to voltage/speed..The saturation thing...now what you said seems to make some sense...so now I REALLY dont know what the heck is going on..lol...yeah the speed is very close to correct as i tested it against a GPS and the CA was calibrated to this motor before I changed the controller...now I am using the hall signal for the signal the CA needs to measure speed, the same way I am assuming it did with the Crystalyte controller.
johnnyz
1 kW
flippy said:
Measure the voltage signal to one of the halls when you rotate the wheel and I guarantee you you have at least a 26 pole motor...something like mine...a motor designed for torque not speed. My Crystalyte h4080 would speed at 115 kph at 72 volts, as it is a low pole count motor (8 pole if memory serves) but under load would only do 72 kph aprox at 5500 watts.
flippy
1 MW
- Joined
- Aug 12, 2015
- Messages
- 2,351
i have a 26 pole motor. i already knew that when i took it apart to change the POS chinesium bearings for proper SKF ones.
and torque, it has plenty of that. its almost comical how fast i get off the line compaired to the ye olde petrol scooters, even unrestricted ones.
but i wnat to get 55kph steady. but that probably means a different motor
and torque, it has plenty of that. its almost comical how fast i get off the line compaired to the ye olde petrol scooters, even unrestricted ones.
but i wnat to get 55kph steady. but that probably means a different motor
johnnyz
1 kW
flippy said:i have a 26 pole motor. i already knew that when i took it apart to change the POS chinesium bearings for proper SKF ones.
and torque, it has plenty of that. its almost comical how fast i get off the line compaired to the ye olde petrol scooters, even unrestricted ones.
but i wnat to get 55kph steady. but that probably means a different motor
Well...im thinking that perhaps we are in the same boat...
eRPM is pole pairs (13 for your motor) x mechanical RPM.
Thinking about it, with your hubmotor you're unlikely to be at the limit for even a low speed controller.
The star-delta thing is how the windings are terminated and can usually be changed without rewinding the motor. If you motor is wired in star then changing to delta would give a 1.7x increase in speed for the same voltage (and the same increase in phase current to produce the same torque). However, I believe delta-wired as standard is more common, so don't get your hopes up...
Thinking about it, with your hubmotor you're unlikely to be at the limit for even a low speed controller.
The star-delta thing is how the windings are terminated and can usually be changed without rewinding the motor. If you motor is wired in star then changing to delta would give a 1.7x increase in speed for the same voltage (and the same increase in phase current to produce the same torque). However, I believe delta-wired as standard is more common, so don't get your hopes up...
johnnyz
1 kW
Punx0r said:
Ok good...I am contacting QSmotors and ask them not only this question but other things that have come up on this post. I can, but dont really want to pull the motor and take it apart...I am assuming that you could tell if I had pics of the inside of the motor?
John
It's not something I've done, just read about on this forum, so it's not something I have experience of. However, if you follow the phase leads inside the motor, they are soldered to the ends of the winding bundles. How the bundles are joined to each other and the phase leads determines the star/delta. If memory serves on most motors, it's just a case of unsoldering, working out what winding is what and reterminating.
it will be good if QS can advise what it is as standard.
it will be good if QS can advise what it is as standard.
johnnyz
1 kW
Punx0r said:
So....UPDATE:...at 91 volts, unladened top speed with Field weakening is 83 KPH, and the wheel so unbalanced it wasshaking the whole bike...however, I am looking into this hubmotor...
Its an 8000 watt motor capable of up to 120 kph with 72 volt...$560 US..just seeing what the shipping would be to London Ontario Canada...I think that a 24s 16p Pack made from Panasonic PF cells will do the trick..with 90-100 battery amps....
x.l.r.8
100 W
If you have the stock tires that are designed for e-bikes that will throw your balance out at those speeds. Fortnine.ca are pretty good at prices and delivery
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