Commuter Booster - <1kg Friction Drive

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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Kepler
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Re: Commuter Booster - <1kg Friction Drive

Post by Kepler » May 24, 2015 10:39 pm

I have played around with the SO6P and RC style motors quite a bit. on a 260 kV motor, 9S is about as high as you can go. I ran 10S 36V no problems SK3 6374 150kv motor.
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Re: Commuter Booster - <1kg Friction Drive

Post by Blanthegenius » May 25, 2015 10:05 am

Folken wrote:Hi guys, I've made an approximate copy of Adrian's bracket and swing arm, and I have a problem: Sometimes, as the drive engages into the tyre, it starts rattling against the stops very hard. It then ends up with bent pin of the swing arm (best case), or the clamp block cracks because of excessive impact force applied to the screw stops. Does anyone know a solution to prevent this rattling?
If you make your bracket from Nylon 66 like in this tutorial it will work.
http://www.instructables.com/id/Frictio ... for-bikes/

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Re: Commuter Booster - <1kg Friction Drive

Post by tomjasz » May 25, 2015 10:43 am

I STILL dream of a Kepler drive kit... Someday.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » May 25, 2015 5:22 pm

Blanthegenius wrote: If you make your bracket from Nylon 66 like in this tutorial it will work.
http://www.instructables.com/id/Frictio ... for-bikes/
I would make the bracket out of Nylon 66 if I knew where to buy it. Did you buy it online somewhere?

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Blanthegenius
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Re: Commuter Booster - <1kg Friction Drive

Post by Blanthegenius » May 26, 2015 2:45 am

Yes I googled and found a few places, here's where I bought mine just recently http://www.directplastics.co.uk
If you click on the free delivery on orders over £50 button a window will appear and at the bottom of that window you will see Rest of the World click the link and send them an email regards to delivery etc.

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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » May 28, 2015 6:44 am

Blanthegenius wrote:Yes I googled and found a few places, here's where I bought mine just recently http://www.directplastics.co.uk
If you click on the free delivery on orders over £50 button a window will appear and at the bottom of that window you will see Rest of the World click the link and send them an email regards to delivery etc.
Thanks for the link!
I'm just wondering, why you chose Nylon over Acetal? Adrian made his original one out of acetal (or was it delrin?)

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Re: Commuter Booster - <1kg Friction Drive

Post by Blanthegenius » May 28, 2015 3:44 pm

I had a piece of nylon 66 to hand at the time of the build which I knew would work and
Acetal and Delrin tend to be used for bearings/bushes. Nylon 6 is too brittle and will most likely crack.

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Re: Commuter Booster - <1kg Friction Drive

Post by ferias77 » May 29, 2015 11:40 am

Kepler wrote:I have played around with the SO6P and RC style motors quite a bit. on a 260 kV motor, 9S is about as high as you can go. I ran 10S 36V no problems SK3 6374 150kv motor.
Tanks for your reply Kepler. I will stay with 7S, and try to upgrade the S06P to 20A.

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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » May 30, 2015 8:17 am

I'm going to pull 35-45A continuous, and am concerned about my ESC overheating. Out of your experience, guys, what ESCs are the most efficient (=produce less heat)? Should I aim for, say, 150A ESC? Will it be cooler than a 80A one, all other things being equal?

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Re: Commuter Booster - <1kg Friction Drive

Post by bose » May 30, 2015 1:31 pm

Check the skateboard / stand up scooter forum for the VESC. Should be perfect for the task. You could write an application for whatever throttle ramp you would wish for that makes it activate smoothly. No need for any external arduino/whatever, all code would run in the ESC.


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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » Jun 17, 2015 6:01 pm

bose wrote:Check the skateboard / stand up scooter forum for the VESC. Should be perfect for the task. You could write an application for whatever throttle ramp you would wish for that makes it activate smoothly. No need for any external arduino/whatever, all code would run in the ESC.
Because I’m not interested in re-engineering the whole system, I’ve decided to buy an off the shelf ESC. This time, 150A and with an active freewheeling design. This is also called synchronous rectification, when the diode in a buck regulator is replaced with an active switch (MOSFET). This reduces losses dramatically, so now my ESC stays cool even with no airflow around it at all. Incredible! Before, I had to open the frame bag to avoid overheating my old ESC. Nevertheless, at the top of a big hill it usually started cutting out because temp protection was kicking in. It was very hot to touch. It was a 100A ESC, and I was drawing 35A. This new ESC just gets to maybe around the body temperature, while sitting in a closed pocket of the frame bag, protected from water. I’m very pleased. Let’s see how it goes.
http://www.hobbyking.com/hobbyking/stor ... oller.html

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Re: Commuter Booster - <1kg Friction Drive

Post by Masure » Aug 07, 2015 1:32 pm

Hi,

I finally made my mounting bracket and did the first test with my friction drive. It's not bad for a first try but I have an issue. The motor disengages itself once the maximum speed is reached. I don't know whether the geometry or the "spring" is the cause.

The spring is just an elastic. Once the motor is at upper deadstop, it doesn't not give much force because it's not loaded anymore. Don't know if it's the problem.

The geometry could be cause too. I don't know if the angle between the rear wheel center and the pivot is enough.

Here is quick video. At full throttle, the motor goes to dead stop and, whenthere is no acceleration anymore, the motor falls.

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Re: Commuter Booster - <1kg Friction Drive

Post by Solcar » Aug 07, 2015 4:16 pm

I think I see the problem. At full engagement, I believe the motor should go slightly beyond the peak pressure engagement point and settle in slightly beyond. Otherwise, if the motor isn't pushing against the tire during heavy assist, like during acceleration, the wheel can push the unit back toward disengagement too easily.
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Re: Commuter Booster - <1kg Friction Drive

Post by Masure » Aug 07, 2015 5:38 pm

Ok i'm clearly below this point. i'm gonna modify my design to get beyond. Thanks for your advice !

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Re: Commuter Booster - <1kg Friction Drive

Post by Solcar » Aug 07, 2015 8:00 pm

Your welcome, good luck!
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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » Aug 08, 2015 3:11 am

Of course the motor will disengage because there is no load. Just test it on the road.

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Re: Commuter Booster - <1kg Friction Drive

Post by EVTodd » Aug 08, 2015 8:02 am

Folken wrote:Of course the motor will disengage because there is no load. Just test it on the road.
Or you can use your brake to provide the load if you're testing on a stand.

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Re: Commuter Booster - <1kg Friction Drive

Post by umejopa » Aug 10, 2015 2:45 pm

Folken wrote:
bose wrote:Check the skateboard / stand up scooter forum for the VESC. Should be perfect for the task. You could write an application for whatever throttle ramp you would wish for that makes it activate smoothly. No need for any external arduino/whatever, all code would run in the ESC.
Because I’m not interested in re-engineering the whole system, I’ve decided to buy an off the shelf ESC. This time, 150A and with an active freewheeling design. This is also called synchronous rectification, when the diode in a buck regulator is replaced with an active switch (MOSFET). This reduces losses dramatically, so now my ESC stays cool even with no airflow around it at all. Incredible! Before, I had to open the frame bag to avoid overheating my old ESC. Nevertheless, at the top of a big hill it usually started cutting out because temp protection was kicking in. It was very hot to touch. It was a 100A ESC, and I was drawing 35A. This new ESC just gets to maybe around the body temperature, while sitting in a closed pocket of the frame bag, protected from water. I’m very pleased. Let’s see how it goes.
http://www.hobbyking.com/hobbyking/stor ... oller.html
I have also diffren problem ESC but most them get killed when motor overheat get in short circuit but this one has worked good even as burn 2 motor with it.
http://www.hobbyking.com/hobbyking/stor ... _SBEC.html
Now with 25A current limit and some peak at 900-1000W uphill the motor last.
How hot does you motor goes ? Mine get about 50-60 degre outside
I run it also on 6S but have 26Ah about 600Wh and using 250-300Wh going to work. Have no speed limit only current .
I think my same speed as same you but have turn it down so it dont overhet on long uphill.
// umejopa
E-Bike friction RC-drive
E-Bike mid-drive

Folken
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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » Aug 10, 2015 10:45 pm

I’m wondering how do you get 1kW at 6S with 25A current limit? :)
After 2 minutes of a very steep uphill at 20kph at 1kW (that’s 45A @6S), the windings of my motor get to 87C. The outside of the motor was obviously cooler (never measured it, as it’s not critical anyway). If I ride continuously at 50kph at 700W, the windings get barely warm. These motors like high speeds.
BTW, I turned off any speed limiting. It appears to be useless anyway (does not give me any significant energy savings).
I never managed to burn a motor or ESC yet. That's after half a year and 3000+ km of use.

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Re: Commuter Booster - <1kg Friction Drive

Post by umejopa » Aug 11, 2015 4:00 am

Well this peak . If the motor take to muth current my interface redus PPM to ECM but it will take 20mS as PPM control are in 50Hz
With RC-ECM we dont direkt controll current as the input is with the PPM controll.
Well i missing temp mesurment in winding. And the code memory are wery few free byte left in the wattmeter
Yes if have high speed on them it is ok but that is the hill the get hot .

//umejopa
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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » Aug 11, 2015 7:07 am

Absolutely, uphill is the worst condition for the motor. I'm just using an infrared thermometer when I reach the top of my largest hill to measure the windings temperature. I keep it simple, so there are no temperature sensors in the system. There is even no speed sensor. :)

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Re: Commuter Booster - <1kg Friction Drive

Post by Folken » Nov 03, 2015 8:06 pm

I’m currently testing the new motor: SK3 5065 275kv. It is significantly longer and 50g heavier than my NTM 50-60 270kv. However, with the new motor, climbing my “calibrated hill” :lol: (600m 10%) takes 10% less amp-hours of my 6S battery: 0.72Ah instead of 0.8Ah. The power is fixed, so this means the motor is more efficient, and I’m now going up the hill 10% faster as well. Not bad!
Although SK3’s axle is only 6mm vs. 8mm of NTM, SK3 has a skirt bearing which NTM doesn’t. NTM developed some minor play in its bearings after 3000km, then I replaced them. Let’s see how long SK3’s bearings will last.
SK3 is also quieter than NTM.
The windings resistance I measured is 35mOhm for SK3 and 44mOhm for NTM. This is probably the major factor why SK3 is more efficient.

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Re: Commuter Booster - <1kg Friction Drive

Post by Hillhater » Nov 04, 2015 5:12 pm

Interesting !
Whilst technically the correct layout, those skirt bearings were previously suspected of sapping a chunk of power ! :wink:
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Re: Commuter Booster - <1kg Friction Drive

Post by FlyX » Nov 29, 2015 12:17 pm

Hello e-bike community!

Im considering to mount a friction drive to my bike, the Commuter Booster seems to be exactly what i imagined :)

Problem is: i only need the support on a very steep hill on my way home, i guess its around 25° slope. Im planning to use the 149 kv Motor on a 3S Battery, that sould equal at about 20 kph top speed.
But i have still doubts if the drive works at such low speed / high tourque, so any experiences with very steep hills?

thx

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