Commuter Booster - <1kg Friction Drive

It's getting wetter in NZ now, so I need to find a grip material to wrap the motor for wet weather. I’m pretty sure this was discussed a long time ago. Since then, a lot of testing must have happened. Can you share your results please? I'm considering anti-slip tape they usually stick to floors and stairs. What kind of adhesive is the best, I'm not sure.

Also, did anyone actually try machining parallel groves or other pattern on the motor can itself? Does this actually help in the rain?
 
About the grooves in the motor casing, my thought is that wouldn't help much. However, people have mentioned that power sander belt material seems to work about the best so far.
 
It would be the best if the grip material could be removable. I have an idea of using a metal can sliding over the motor. The grip material is on the can's surface. For dry weather, one can easily remove the can to avoid too much tyre wear. I'm tempted to go to my local supermarket with my calipers to find a suitable tin can. :D
 
I had the belt sander material stuck with contact cement, lasted 2 years until no grit left (though went through two tyres, small price to pay for great performance). No lifting at all. Went with the same again, works great, highly recommended.

I think it would be difficult to prevent a steel can from slipping on the motor can.
 
I've decided to stick some self-adhesive anti-slip tape to the motor. There are no signs of it coming off or wearing out after several days of use. :) I've applied it in spiral pattern, so there is no joint perpendicular to the tyre. Puddles are not a problem anymore! Also, the power losses became lower because I don't have to deform the tyre as much as before.
 
Grinhill said:
I had the belt sander material stuck with contact cement, lasted 2 years until no grit left (though went through two tyres, small price to pay for great performance). No lifting at all. Went with the same again, works great, highly recommended.

I think it would be difficult to prevent a steel can from slipping on the motor can.

What kind of contact cement did you use? The belt sander material is grit 40 I presume?

Unfortunately, my anti-slip grip tape is already showing some signs of wear, so I'll have to replace it soon. :(
 
Folken said:
What kind of contact cement did you use? The belt sander material is grit 40 I presume?

Yep I think its 40, if you can get 60 or 80 that would be OK too and possibly less tyre wear.

Here's the glue I used, but the brand wouldn't matter. I used the "spread on both bits then wait for it to be almost dry before bringing together" method.
20150424_153941s.jpg
 
Thanks guys, I've glued a 60 grit sander belt using Selleys Kwik Grip contact adhesive - that's what was available in my local shop.
PS. Looks like more people are using 50mm motors! Good! Adrian was too quick to rule 50mm motors out. I wonder how small can you go without overheating motors...
 
Hi there,

As I said, I want to replicate folken's work. Even if I understand the whole picture, I'd like a quick validation of the wiring before I go further.

Notes :
- 3 phase motor and dlux controller are not accurately drawn. I just put a DC motor and no controller on the diagram. I understood I have to wire the 5v, gnd and d3 pwm to the controler.
- screen connection is not drawn

folkens%20nano%20controller%20%28Custom%29.png


And what I have done so far (not so far :F) :
- connector to hall sensor soldering
- voltage divider soldering

20150503_121803%20%28Custom%29.jpg


Any advice appreciated !
 
Masure said:
Hi there,
As I said, I want to replicate folken's work. Even if I understand the whole picture, I'd like a quick validation of the wiring before I go further.
Looks correct so far. I'm not 100% sure if the code will work without the LCD connected though.
 
Hi Folken,

I did some work on your circuit and here is what I have :

Soldered all the I2C interface pins to the screen in a compact block. Not so easy !

20150509_200135%20%28small%29.jpg



Soldered all the arduino circuit. Not easier !

20150510_194128%20%28small%29.jpg


The small DC DC switching convertor fits very well in the box. I recommend it.

I tested and adjusted battery voltage read from your program and that's all for now.

I have not tested current reading from the hall sensor because I have nothing to test with. I'd prefer not to check directly with motor + controler until I'm not very confident with your code.
 
Hi folks,

I'd some help here. I plugged the motor in and it does not start by itself. It's stuttering and can start if I retain a little the can. No idea what to check.

https://www.youtube.com/watch?v=SPM6TMCDjm8
 
The first thing I would do is connecting the ESC to a servo tester. If the motor rotates with no issues, then the next step is to find out what ESC pulse width is actually produced by Arduino.
 
Thanks for your advice, I managed to get a servo tester but it was a not better. Then I found the issu => too weak voltage with the power supply I used (15v) :oops:. Using my 6S battery did the trick.

I'm now working on the bike mount design. I also have to perfectly understand the code. I didn't even check the real current value to compare it with what the arduino reads and display.
 
Hello to all,

I'm looking to increase my battery life for my current assisted friction drive system.

I have the following components:

Motor Brushless Outrunner = 63/74 KV200 PowerW 2940, Wire Winds 8, Resistance(mΩ) 37, Idle Current(A) 2.3, ESC(A) 90, Cells Li-Po 4-10
ESC = 85A BlueSeries SBEC
Batteries = x2 - 5000mAh 5cell 18.5v

I travel 12 miles round trip to work and back and use the friction drive system off and on throughout the journey to assist.
15 times on the way into work holding it down for about 4-5 seconds and
19 times on the way home for about the same 4-5 seconds at a time.
I find myself having to re-charge the lipo batteries every day

What setup do you have and how long do your batteries last?
And what would you recommend for increased lipo battery performance please and thanks.
 
4-5 seconds at a time?! That's no fun!

My setup is 2x 6s 3Ah (133Wh total).
Motor run time for half-hour 15km commute trip is 19min. So I'm using my motor more than half of the time with an average power of 420W.
Charging at work as well, of course, as the battery goes flat within the last 500m of every trip, exactly as designed (unless there is strong tail wind).
30kph average speed on my cycle computer, 40-45kph cruising.

PS. Tried turning off speed limiting. Result = 55kph @700W. :twisted: But the battery will go flat in 10min in this mode.
 
Cheers for replying Folken,
Looks like you have got a pretty decent set-up, do you have a link to your build you could share or not?

At first I was buzzin' about having built the friction drive but now i'm getting more used to it, I'm wanting to increase time and speed too. :D

I don't know what would be the best cause of action to take
increase the lipo amp hours
or change motor or both, still pondering.
 
It depends on what are you trying to achieve.
You can get a rough idea of what is achievable here: http://www.commuterbooster.com/performance

In terms of power, 300W is boring, 450W is my preference, 700W+ is for steep hills or for setting speed records.

PS. I've already described my build here, with photos, a couple pages ago.
 
adrian_sm said:
Good question. The cheapest and easiest alternative to my fancy "Brain Box" is actually and very cheap off-the-shelf controller.

The S06P magically works very well, at both 24V & 36V.
The key is the ramp rate of the throttle, and ability to spin up these small motors well which is not the case with many controllers. There may be alternatives now available, but this is the one I know to work.

Here is a link:
https://bmsbattery.com/ebike-kit/545-s06p-250w-torque-simulation-square-wave-controller-ebike-kit.html

Hi everybody,

I tried a "commuter booster copy" 3 years ago on a folding bike. I had tire wear problems... but I think my setup was not correct.

I would like to retry it on my recumbent bike.
I have a Turnigy Aerodrive SK3 - 6354-260kv : http://www.hobbyking.com/hobbyking/store/__18127__Turnigy_Aerodrive_SK3_6354_260kv_Brushless_Outrunner_Motor.html
I tried the motor with a S06P. It works with a 24V ebike battery (7S lipo).
But with a 36V battery, impossible to go higher than 50% throttle, then it stops. It looks like the motor is too fast for the contoler...
Adrian_sm, what motor do you tried with the S06P controler ?
 
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