Commuter Booster - <1kg Friction Drive

[Kepler]

Yes, welcome Adried. Great solution for a throttle mount on a road bike. I can see this idead being taken up very quickly

[Kepler]

I meant holes on the arms for mounting the motor. I believe 5/32" is right (error in post) but I don't have a motor on hand to try.

Adrian: so you think the big 63-74 (the one you're working with) will be okay on a little 85A esc? Are we talking about using no motor under 15 kph?
I'm also interested in the Hyperion Z4045 solely because I don't want to deal with hobby king right now. They just sent me a $130 helicopter kit instead of my $30 charger. Are any extra parts required for the Hyperion Z4045 (I can get it for $84)?

Is it straight forward using the servo tester to control the esc?

I have done plenty of testing with the 85A 63-74 combo. Works quite well but does get quite hot under constant load. I have had them tripping out on high temperature quite a few times but never actually hurt one. The 100A gives you a bit more head room.

The Z4045 is a nice motor. Bolt pattern is 25mm centre to centre. As this is 48mm motor, go with the 320 kv since speed is what you are after. Main negative with the Hyperion is that the bearings are quite small. I ended up retiring mine due to noisy bearings and not being able to find replacement bearings for it.

[adrian_sm]

ES Post - throttle

Okay I need to start getting the electronics sorted out for this drive. My options are either the mythical Kepler interface, or a custom one. Let's talk about the custom one. 

So I was thinking of starting off with the Turnigy Watt Meter, making the shunt remote (thanks Jeremy), then modifying the software to do a few extra things (thanks Jonas). Here is my wish list:
- throttle interface to go from hall or buttons to the RC ESC input
- current limit, reduce PWM when limit is exceeded
- speed/distance display, will require a wheel speed sensor input
- minimum speed for friction drive, throttle set to zero below threshold speed
- 5v output for MagicShine style headlight/taillights from ESC BEC
- display mounted in custom waterproof enclosure on handlebars
- shunt mounted back at motor/ESC
- switch to turn it off/reset Ah/Wh/distance
- button to switch between display modes
- on/off switch for lights

Display modes I am thinking of having are:
1) Speed, distance, Wh/km, Wh used
2) Speed, distance, Ah/km, Ah used
3) Speed, distance, power, Wh/km instantaneous 
4) Speed, distance, Volts, Amps

So to do this I need some extra inputs:
1) mode button
2) wheel sensor
3) throttle input

And the throttle output. 

Now I need to see if this is all possible with the number of extra IOs available, and the programming options, space, speed we have available. 

- Adrian

[Adried]

Hi,thanks for the reply .Hope i can help for this throtle problem.I use it now 10 weeks on my roadbike with hub wheel 700c23.This system works perfect you can choose te right position with the parts on the photo.No problem to switch the gear.First photos campa,and i use shimano by my self.Ergonomics ,it is verry fine to use when you have found the perfect position.Photo with all the parts

[adrian_sm]

Very nice work.

That final photo makes it crystal clear how to build your own. Thanks a lot for sharing.

- Adrian

[umejopa]

Adrian I think you can have this but may change Up to ATtiny461 or 861 to get some free code space.
http://www.atmel.com/dyn/resources/prod ... oc8273.pdf
For button you can use a A/D input and get ex 16 input , Speed you have one free I/O for that.
Then you need to make some more change in program but that I think it will work.
//Jonas

Quote Adrian
So to do this I need some extra inputs:
1) mode button
2) wheel sensor
3) throttle input

And the throttle output.

Now I need to see if this is all possible with the number of extra IOs available, and the programming options, space, speed we have available.

[adrian_sm]

I was really hoping to not have to make significant mods to the PCB like swapping for a bigger attiny. Being a Mech Eng my skills and patience with a soldering iron are limited, and little surface mount chip soldering is definitely outside my skill set.

Think I would prefer to limit what I try to get it to do instead.

Only just started looking at the assembler files now, and it us making my head hurt. I'll need a lot of help if I am going to make these changes. Any recommendations from people on where to start getting my head around the changes I would like to make. I haven't done programming in about a decade.

- Adrian

[adrian_sm]

To answer my own post. I found this resource for programming these.
http://www.attiny.com/assembly.htm

- Adrian

[hillzofvalp]

DO you think that 8 gauge copper wire will be just right for this application?

[adrian_sm]

What for the spring? Haven't seen too many springs made from copper, the yeild strength would be too low at a guess. Justplug the figures in to an online spring calculator and work it out for yourself.

Personally I would just find a real spring and modify.

- Adrian

[hillzofvalp]

I meant for handling 100 amps of electricity. I would never make a spring.

I noticed that the 63-74 motor has the casing screws. would it be possible to cut a piece of slick bike tire and wrap it around, securing it with washers and screws that are a little bit longer than the ones there? I think it would make the most sense if the two materials coming together (bike tire and motor) were the same. It would definitely bite in a lot more than bare---and could withstand some pounding. Just a thought.


Is there a way of drilling perfectly spaced holes in aluminum without a jig? I just marked them with pencil but I can never get them all absolutely perfect in line. Is there a tolerance with hole placement? I haven't ordered my motor yet to test fit.

[adrian_sm]

Kepler and a few others have tried this and all come to the conclusions that it is not good when wet.

I would bow to the experience of others and stick with the belt sander/grip tape type solutions given your two week time frame.

As for the 100 amps and 8 gauge copper wire. It will be fine.

- Adrian

[adrian_sm]

Is there a way of drilling perfectly spaced holes in aluminum without a jig? I just marked them with pencil but I can never get them all absolutely perfect in line. Is there a tolerance with hole placement? I haven't ordered my motor yet to test fit.

Use a centre punch to make a small indentation in the metal. Then the drill bit won't wander when you drill.

Personally I would just wait until you get the motor to drill. Just to make sure you get the spacing right.

- Adrian

[hillzofvalp]

A punch?

What is the real advantage of going with the HV160 for $225 on ebay? I know it can accept a lot of input and take a lot of current. It's also a US manufacturer with high reputation I believe.

Also, I'm trying to stay away from hobbyking right now. I still have one of their helicopters that they sent me by accident.

Do you know of another source for the 63-74 motor? For some reason I want to get that motor, I'm not 100% sure why. MAybe because it's big and it's the one your using. I will try a different motor it's just that I'm not sure I could match the performance of the 63-74. Advice?

Thanks.

[adrian_sm]

Phew. A lot of questions.

Centre punch:
http://www.google.com.au/search?q=centre+punch&ie=UTF-8&oe=UTF-8&hl=en&client=safari

HV160:
High quality, more features, less likely to fail

63-74 alternatives:
No idea. I just went with the cheapest options, to see if I could make it work.

- Adrian

[Adried]

E bike controller with friction bike motor
http://www.youtube.com/watch?v=JRuuM-1P ... er&list=UL

[spinningmagnets]

Yes, there was a discussion a while back about the option of adding hall sensors to the RC motors. There is no plug-and-play kit for sale anywhere yet, but all the details and pics are just a quick ES search away. You would have to order the hall sensors online, and then fabricate a bracket to hold them in the proper place.

http://endless-sphere.com/forums/viewtopic.php?f=30&t=15686

ES member Gwhy has added halls, and is using a conventional E-bike controller from ES member Lyen. I believe the controller with the minor mods neccessary was less than $100.

http://endless-sphere.com/forums/viewtopic.php?f=2&t=16910#p249247

Plus if you have added halls to an outrunner, another controller option that doesn't require mods (for a slightly higher price) is the 6-FET from ebikes.ca

http://www.ebikes.ca/store/store_controllers.php

One of the major benefits of using the tiny RC ESC-style controllers is that they are very small and light, which is clearly one of the goals of this build. If you also want a tiny ESC, the Castle-Creations HV-160A has proven to be the best. Though I suspect the 120A "might" be adequate for this build, the greater heat-absorption/shedding of the 160A is an available insurance. The 160A also allows for future performance upgrades.

http://www.castlecreations.com/products/phoenix_ice_hv.html

[hillzofvalp]

Can't I just run a little fan over the hv 120? I think it's a $100 dollar difference between the 120 and 160. I think I might go all out and get the 160, and have it for other future ev projects. As for the Hyperion ZS 4035, I can't find any hard testing of it for this application. It does have a smaller 6mm shaft, almost half of the turnigy 63-74. I would really like to avoid hobbyking, but idk if the price will justify dealing with them.
Also, what capacitors would I need to buy for my hv 160/120?

Adrian, just to clarify things, I go back to school around the 10th, and my primary goal was to have all fabrication out of the way. I don't need to have everything finished by the 10th. The other issue is that I don't want to order something and it not get to the right place at the right time. But the primary issue is fabricating the arms and mount. I'm going to go check out the lbs. Btw, if you think that posting in your thread is inappropriate, I will start my own thread. I see it more fit to start one when I actually have a prototype.

Lastly, would it be possible to rewire a servo tester with a different form factor pot? couldn't I fashion a nice trigger I can mount on my handlebar out of an old rc remote and wire it in into a servo tester? This way you could incorporate a spring mechanism that is more practical than physically turning the pot down when you want to slow down, very similar to thumb throttles. Here's the assembly out of the stock Losi Mini t RTR:


am I missing something, or is this not the easiest way to go? I would try mounting it right where the brifter rubber hoods start, cause I ride up there a lot while commuting. I could have my stonger fingers on the brakes and my ring or pinky on the throttle trigger. It could even be mounted on the side of the brifter, and the trigger could stick out parallel to the brake lever.

update: just pulled these off my old bmx bikes. One is from a powerlite p19 (pictured). However, my other dyno threaded bmx stem is zero rise and might work splendidly if I modify the clamp hole that is designed for 3/4" handlebars. MOdification would involve cutting off the post that goes into the fork.

Solution to mounting on seat tube issue:

though I don't think I should've made that cut. I should've gone at an angle so that, when tightened, this piece won't flex. Oh , well. It should work.

[spinningmagnets]

hillsofvalp, I doubt you will make your timeline, this field is still very new and experimental. There are simply no guarantees that if you "do this, you will get that". I recommend that it would benefit you to start a new thread (though it is not required). I guarantee that every step will take longer than you think it will...

Regardless of the motor "kV" selected, if you use something from the 63mm diameter family, and use the motor-shell as the drive-roller (2-1/2" roller), any ESC with a continuous rating of 100A (or more) should be fine. If the selected ESC has caps already, the factory caps should be adequate. However, if you need to add caps (two caps should be enough), here are my recommendations:http://endless-sphere.com/forums/viewtopic.php?f=28&t=21197&start=15#p325342

You haven't mentioned if you plan to use 6S (22V) or 12S (44V), If 12S you must used a "HV" ESC (High-Voltage) from any one of several manufacturers, if only 6S, you have many 100A+ ESC options, depending on desired features. If you use 8S or 10S, get a 12S-capable charger and a 12S ESC, or you might not be able to sell them later.

Matts E-bike systems use a 12S RC-motor to drive the axle, and after he has tried everything, the HV-160A from CC is the only survivor. If you have a separate friction roller that is a small 1.0"/1.25" diameter (Like EVTodd, and also me) a 70A ESC has proven to be adequate, with 85A being useful for heavy duty.

[hillzofvalp]

Thanks for the info. I may or may not have mentioned that I'm running 7s 26650s. Getting a hyperion 1420i.
I don't need to have everything working by a set date.. I just wanted to avoid bringing a bunch of tools to school.
Turns out I have access to a bunch of tools at school anyways (ev club), it's just a bit more tedious.
I'm considering just building up a front hub wheel, though I'm concerned that my fork/headset won't take it (lightweight racing frame and old headset).
If I bought a castle HV 120 would I be able to use it with a front hub motor if my friction project falls through?

[adrian_sm]

Btw, if you think that posting in your thread is inappropriate, I will start my own thread. I see it more fit to start one when I actually have a prototype.

I reckon you should start your own, since you seem willing to modify things, and do them a bit differently your build will likely morph into something that isn't a direct copy of my evolving design. Then you will also get a better record of your build in one place, as well as getting better input from others.

Lastly, would it be possible to rewire a servo tester with a different form factor pot? couldn't I fashion a nice trigger I can mount on my handlebar out of an old rc remote and wire it in into a servo tester? This way you could incorporate a spring mechanism that is more practical than physically turning the pot down when you want to slow down, very similar to thumb throttles. Here's the assembly out of the stock Losi Mini t RTR:


am I missing something, or is this not the easiest way to go?

I like it. What sort if pot do these have? 5k? What range of motion? I really like the idea of a trigger throttle, I just hadn't found a good pot/mechanism I could use. This could be just the ticket.

- Adrian

[spinningmagnets]

No idea about the CC HV-120A ESC running a hub, who knows? edit: adding a small fan to any ESC is always a good idea.

hillsofvalp, If you are a gambler, you have a few of the more-affordable options for 7S. I am using the Miking 120A ESC, and some of the Mystery ESCs are rated for 7S. Search carefully though, two seemingly identical 100A Mystery ESCs will have specs with one maxing-out at 6S and the other at 7S...ALSO! some will list the volts as 7S, but on the same page its also listed as 22.2V (which is of course, actually 6S). Best of luck...

120A 7S Miking (with integral BEC)
http://cgi.ebay.com/120A-Brushless-Moto ... 45f7c23209

120A 12S Turnigy (no BEC)
http://www.hobbyking.com/hobbyking/stor ... oduct=8921

120A 12S Mantis (no BEC)
http://cgi.ebay.com/Brushless-ESC-MANTI ... 2a09bead88

120A 7S Force-Control (with integral BEC)
http://cgi.ebay.com/120A-Brushless-Moto ... 588be80757

120A 10S TurboRIX (no BEC)
http://cgi.ebay.com/New-RC-Plane-High-V ... 3ca2f7bdd1

120A 12S Hobbywing (no BEC)
http://cgi.ebay.com/Hobbywing-Platinum- ... 45f156b369

100A 7S RC-Smart (BEC not listed)
http://cgi.ebay.com/RC-Model-100A-Brush ... 45f60ce6b5

100A 7S RC-Timer (no BEC)
http://cgi.ebay.com/RC-Hobbies-ESC-100A ... 1c0b5c5c41

[LI-ghtcycle]

Great stuff! I have a "Mystery Meat" ESC, the 100A variety for 6S I believe, if I understand correctly, you're having good luck just using the "auto detect" method i.e. just plugging it in and letting it decide your cell count based on voltage, or do you program yours?

Thanks!

[hillzofvalp]

Do the above ESCS work with hub motors? And for clarification, 7s M1 is 3.3x7V not 3.7x7V.. so 23.1V (not 25.9V).

This trigger has about 18 degrees movement in forward and "reverse" directions. If connected to a hub motor it would allow you to brake. Might be able to re align to skew towards a max of 36 degrees travel, but I'm not sure you would want to do that. Also, (to my surprise) it is a 5k pot. I'm pretty excited about trying it. It could be an easy way to brake too, with negative trigger.

The Losi radio I have is one of the cheapest radios you can buy. More expensive than I thought though (got mine with complete kit). ~$27 shipped with a quick ebay search:
http://cgi.ebay.com/Team-Losi-CTX1000-2 ... 680wt_9077

I was looking forward to CC ESC because I could log data, interface and program with a pc. Thanks for all of your links, I'll look into it more. One thing that boggles my mind is how small these are with no heatsinks. How would I cool them even with a fan? there's no place for the air to go.

As for starting my own thread, i'll get on that tomorrow. With regards to friction drive, I was able to get 4 perfectly cut arms (rectangular, 152x54mm ). My step dad took the Al sheet to US Steel . Exactly how much trouble will I have with friction drive? I know this method is in testing in all.... but can't I just slap it on there with a door spring and make adjustments by sliding the mount up and down and drilling, say, 10-15 settings in the arms for adjustments? If I get a hub motor I'll have to run more wire, have a $350 wheel built up to my liking, and possibly even ramp up my battery capacity if necessary. For some reason I am thinking that hub motors take more energy, but friction drive isn't as efficient. Initally I'm going to be running 4.6Ah and I don't know if I could use a hub motor for a minute. (this should go in my thread, sorry).

[spinningmagnets]

I don't know if anyone has used an RC-ESC to control a hub-motor. You might be the first to try that. Please post the results if you do.

I just posted those ESCs as cheaper options compared to the Castle Creations 120A ESC. If you use a Castle Creations 120A for this application, you will not be disappointed. I have used the Miking ESC, and it seems to be working OK for me, except the LVC doesnt work on it. I made a point of saying "If you are a gambler"...every cheaper option listed is a gamble, so, "do you feel lucky"?