FS: Commuter Booster Friction Drive Beta Units

[adrian_sm]

Hey,

Thanks for thinking of my needs, I appreciate it.

Pretty dodgy assumptions on the power formula. But I think that is probably what my $7 bike computer does to calculate callory consumption.

I really see tire wear as a non-issue these days. Early on I was using the grip tape to get more traction between motor and tire, but that was because I had no real power limiting on the electronics resulting in stupidly high torque and power. Now that I have things dialled in with the Brain Box, it smoothly ramps up the power delivery, and peak power such that I now just use the bare shell of the motor exclusively on all my bikes with the Commuter Booster. Gives plenty of traction in the dry (which is all I rid in these days), and has no effect as far as I can tell on tire wear.

I don't know for sure why the trainers sue the elastomer rollers. I haven't really looked into it. But I do know on my cheap trainer I gave up on using it as a dyno load because it has really poor heat sink design. This means all the heat it is absorbing from you pedalling or the motor driving he wheel was not getting expelled into the air very well. Resulting in the actual roller that contacts the tire heating up, a lot. So much I could smell the tire rubber, after only a very short test. Now that would affect tire wear. Especially with the small roller diameter and amount of tire engagement.

I can't see how the elastomer/tire contact combination would really help in the real world. In the wet it would still suck as it does nothing to cut through the boundary layer of water that gets drawn into the contact region. And in the dry the bare motor/tire contact works fine.

Actually thinking about it more this is my list of why they would use the elastomer for the trainer rollers:
1) heat insulation
2) radial deformation of the elastomer means less deformation of the tire -> less wear and tear on tire
3) tangential/axial deformation of the elastomer possible, resulting in less sliding shear between tire and roller as the tier conform to the roller shape -> less tire wear.

For the commuter booster (3) is taken care of by using the smooth shell of the motor, and allowing a small amount of sliding between the tire and motor as the tire conforms to the motor shape. (2) is a pretty minor concern, & (1) is possibly a concern if running the commuter booster very hot, but if you want >1000w you probably shouldn't be using the Commuter Booster anyway.

I would still really like to get some sort of dyno load setup up so I can test motors. It would be nice to know what the continuous torque limits are for motors. This would allow me to more sensibly set up the Brain Box to protect the motor, while still maximising power.

- Adrian

[deepfraught]

About the trainer elastomer roller, they only provided loose marketing "50% less noise, 30% less tyre wear", no detail on the scenario, what it is being compared to (metal roller presume, etc. etc.
The Kurt Kinetic claim to know their fluid resistance behaviour by power tap to calibrate their dyno to use that formula. They assert it being repeatable and reliable.

[DavidD]

oh, now I know why I'm waiting so long for a package from HK- my LiPo and balancer/discharger are still on backorder

I'm having the same problem, its been over a month since I made my huge HobbyKing order and have nothing to show for it. On the plus side the CB hardware is all here and looks great. I finally gave up and had HK cancel that part of the order and give me some store credit.

Does anyone have a recommendation for a replacement charger other than this guy? Bonus points if its in the USA warehouse, since that one is across town from me and the global warehouse is across the world.

Are there some wattage numbers, battery types, or connectors I should be on the lookout for while I'm searching for something? I'm still new to this electric drive stuff, its like trying to grab onto a moving train. Not as hard as catching up to a moving plane though.

[adrian_sm]

This one is in stock in the US warehouse, and should do the trick.

http://www.hobbyking.com/hobbyking/stor ... se%5F.html

And if you need a power supply too this one looks about right, as long as you have a spare power cord for it
http://www.hobbyking.com/hobbyking/stor ... se%5F.html

[deepfraught]

My first chapter with CB and feedback on the 50mm motor after a few rides (cut short). I'm very happy with my new road bike flat bar commuter mk2, and the CB complements my goals for a great bike with/without electrics, and no real "battery range limits" using pedal power and infrequent bursts of the CB for faster climbing.
I loved the smaller size, ran it with default brain box settings 500W with a 5Ah 6S battery in a slightly modified water bottle tool container in 2nd water bottle holder, carrying identical spare battery in my rear bag to be swapped on at work for return commute in lieu of a 2nd charger kept at work.

CB kit first installed on Roubaix

The motor and controller have blown after two stuck throttle button incidents. The motor came loose shortly after the 2nd stuck throttle incident, so I didn't use it enough to kill it that day. Next use first hill climb caused total motor burnout and subsequently found a dead ESC also.

Burnt out 50mm, new 63mm to try

I am now looking to:
- upgrade to 8Ah 6S batteries
- new controllers (no stock at Hobby King again - any tips for alternatives?)
- new spare 50mm motor
- but will first try the 63mm motor I have. I had the 63mm set up last night replacing the dead 50mm, but no-load test found the controller was dead from the motor burn out

First full test of the 50mm was about 13 climbs (mostly freeway overpass elevations) over a 20km commute trip home which is the more uphill trip (more downhill or shorter climbs into work).
I engaged it on the flat early enough to get up to speed (instead of dropping down a gear and spinning legs up without motor), then could hold higher gear and pedal assist as it flew up in anger (I do like the noise in a "coming through!" warning aspect for regular cyclists climbing ahead). It was after dark, so it felt like a rocket, insanely quick with the typical faster feeling from reduced vision in the dark (unlit cycle paths). In daylight I had time to look at my cruise 32kph, that increased over 40kph with CB engaged and wound up to speed before hitting the hill.

I liked that it is noisy, in tandem with my single 5Ah battery, it kept me honest to only use it for bursts of climb assists and not the majority of the ride.

In the wet, any hint of damp road/path and I couldn't get traction. When it was nearly dry, it was easy to see dry patch to damp patch, and if running over a non-dry patch it would slip after running over any hint of moisture. The great thing was it didn't matter, without the assist it is still a fast road bike. I've been over 2 weeks back on road bike commuting again after 4 months with the A2B Metro.

The only setup catch I had was tMin at 1100 being too high for the ESC, so Adrian advised tMin 1000 and problem solved.

Congrats to Adrian on such a good kit already with still more potential, it's made my best road bike become my best (dry weather) e-bike now. I have cycle commuted every working day this year, and even when tinkering all night with only 2hrs sleep could still get to work taking it easy on the way in, with assist for the way home (it was dry that night).

[adrian_sm]

Hey deepfraught.

Great to hear your experience with the Commuter Booster. Would you mind elaborating a bit on a few points.

The motor and controller have blown after two stuck throttle button incidents.

What caused the stuck throttle? One possibility is the button not being free to move in the hole in velcro securing strap. This is usually fairly obvious when first mounting it, but things could move during a ride. I have had an electronic stuck throttle once during my testing, but this was many firmware revision ago. Would be good to hear your thoughts so this can be solved, and avoided for others.

Here is a reference image for those not familiar. This is an early prototype, but shows the button and the securing velcro strap.


Also what caused the motor to "blow". I would have thought at 500w your 50mm motor would have been all right. Guess not. The only 50mm motor I have killed was before the power limiting of the brain box was introduced, and I was running it without a power limit and dumped way more than 1000w into it for a long up hill climb. Would really like to understand how it happened, so I can see if I can do something about it. One thing I have in the works is a torque limit, which basically restricts power at lower speeds when the motor is its most inefficient, resulting in limiting waste heat. This should really help. The other thing is I think the recent firmware versions now have a bug where it does not cut the throttle when you drop below the minimum speed.

Oh, and when I fried my motor the shorted windings in turn fried my ESC, just like you.

If you need a replacement ESC, I have some in stock now, just email me if you want one and we can sort out the details.

The motor came loose shortly after the 2nd stuck throttle incident

How? Was it the four securing screws coming undone? Or a failure of the Commuter Booster?

In the wet, any hint of damp road/path and I couldn't get traction.

Yep, with the smooth can this is normal. If you need wet traction then you will have to do the sand paper wrap of the motor trick. It improves traction, but results in increased tire wear. I always run smooth can in fair weather, and swap motors if it is going to be a bit damp.

without the assist it is still a fast road bike.

That is the essence of the commuter booster, and the reason I have spent so much of my time making it. I still remember the first time I had to pedal my 30kg hub motor bike. I was blazing along at 40kph without a care in the world, when I ran out of juice or something broke. Suddenly I was stuck on this heavy bike, that had the drag of a hub motor, and I was 10kms from home. Quite a contrast. Now I regularly ride a road bike with the commuter booster on it, and forget it is there.

Congrats to Adrian on such a good kit already with still more potential, it's made my best road bike become my best (dry weather) e-bike now.

Thanks. Now lets see what we can do to make it even better.

- Adrian

[deepfraught]

[quote="adrian_sm"]Hey deepfraught.

Hi Adrian, stuck throttle was like that, from the momentary throttle button having a side action, so at one time it was after a tight turn my grip changed, and second time standing over bike jumping back on to cross traffic lights my grip had changed, pulling it enough to engage. It must have been just above 6kph walking speed to be able to engage. Given how I've used it only for cruise speed climb boosts, as initial safety I can bump the low speed limit up to 12kph to cover the times it happened. Better still I was thinking of modifying one of the many reflector clamps to recess the button in there, so no clamp movement like the velcro. I also thought a brake cut switch on the throttle would stop the throttle when rear brake is applied, but not addressing the root cause which I think the reflector clamp mod will do.

The motor blowing I presume was from the high load for the seconds each time it took me to stop and fumble to stop the throttle. The final death was up first hill on way home, after the charred winding pic of the night before, it engaged for a bit then faded and cut out before top of climb.

The first throttle stuck time may have been longer stuck, but it was when the road was damp so the motor just spun freely, actually no issue with that time now that I remember that it was wet.

The second time I knew what was happening so stopped it quicker, but it was in the dry, and really trying to grip and drive. Immediately afterwards I could smell the winding burnt, but it wasn't dead. I used it a bit more later that ride, the loose motor screws to CB arm then made an appearance. I don't remember how tight I had done them, probably just lightly from first fit and my mistake never checking.
FYI I also got a flat front tyre in office before leaving on the same night as stuck throttle and motor screws falling out, so you can see I'm the perfect tester with my bad luck =D

Regarding low speed cutout I was stopped for a couple seconds when it was still driving so I don't know what the low speed cutout time delay is or if it was the firmware bug. I presume the time I went from under 6kph to stopped was a couple seconds, and then a couple more second when stationary it was still driving. I don't know if it was me unsticking the throttle that stopped it, or the cutout. I would be able to test for cutout with a wet tyre and same button mounting without consequences as it would just slip.

Re: wet grip, I won't bother. We had nearly driest July on record before last couple days of month. In the fine weather I got this frame, built it up, then got the CB going, by which time we had 2 weeks of rain =D Still being a great ride with CB onboard and not in use, I'm fine going without in the wet since it's not critical to use it and rain is infrequent enough here as you know, 9 dry months and probably only 1 month of regular showers that would keep the road damp. If running a "winter bike" I could see it convenient enough to leave a wet version on, but I'm so happy with this bike alone I'm going to clear a few bikes out.

I'll email you about the ESC, thanks no waiting for Hobby King stock! Then I will step up with the rest of the big boys using the 63mm motor =D

PS: I understand the moderation of the 500W limit more now, I didn't feel the need for more, and can see if you are at speed with 500W you could press as required to get 1000W, but for short climb uses with pedal assistance the 500W flattens the hill and you can still provide your input to not need 1000W from the motor.

[adrian_sm]

Cheers for the info.

Sounds like the firmware bug may have compounded the stuck button issue. Prior to the bug, if you drop below the minimum speed it immediately cuts the throttle. Which would have stopped your stalled motor from soaking up 500w of heat. As would the yet to be released torque limit feature.

I have a new throttle design in the wings, but my attempts at silicone casting have been pretty average. And I am not ready to pay someone else to manufacture my design quite yet. But this would totally eliminate the failure mode you had.

I'm so happy with this bike alone I'm going to clear a few bikes out.

Glad to hear it. Once I started using the commuter booster my hub motor bike got left alone for so long that my BMS killed my headway pack due to a slow drain.

Then I will step up with the rest of the big boys using the 63mm motor =D

Not sure if the 63mm motor will fit the 50m swing arm. Mounting screw pattern is different, and the swing arm is shorter so there is probably not enough clearence to the clamp/pivot block for the larger diameter motor. But I can provide a standard ( 63mm ) swing arm if it will fit your frame. Let me know.

PS: I understand the moderation of the 500W limit more now, I didn't feel the need for more, and can see if you are at speed with 500W you could press as required to get 1000W, but for short climb uses with pedal assistance the 500W flattens the hill and you can still provide your input to not need 1000W from the motor.

Yeah. the 500w goes a loooong way on an efficient road bike. The 63mm motor can take a lot more, but I never seem to bump up the power.

[deepfraught]

I originally got the 63mm beta release from you so using that swingarm, then the CRX City I was going to use didn't fit it so you gave me a 50mm swingarm. Just the ESC holding me back now.
My wife asked about bikes oddly, so the A2B Metro would be good for her, and I got a Tyke Toter front seat for it to take our 2yo daughter on the bike which A2B Metro is also best at. Low seat height for stand over since front seat takes your stand over room, means no pedal efficiency, so hub motor is good for. When our 6 month old boy is old enough for a stroller/trailer towed, I can let our daughter choose with him or shotgun up with Daddy =D
Like a mullet hairdo, Commuter Booster up front for business, hub out back for pleasure =D

[adrian_sm]

Like a mullet hairdo, Commuter Booster up front for business, hub out back for pleasure =D

Is that a pitch for a marketing slogan...

[deepfraught]

The only change in hindsight I thought was to replace "pleasure" with "leisure" because it alludes the CB is not pleasurable. So here's my Gruen effort:

Commuter Booster up front for business,


hub out back for leisure.

That's alluding to Cadel Evans with the Alpha kit CB winning Tour de France, and Leornado DiCaprio on an original A2B Metro representing the hub

[adrian_sm]

Short video of the Commuter Booster on a road bike that shows the drive engagement.
Apologies to those that have been asking for it, I know I took a while to make it. But I now have a really nice boom mount for my GoPro.



And here is the longer version, around the block. (Still uploading at the moment)



A couple of notes:
- The drive was set up at 500w battery side power.
- The audio makes the drive sound a bit louder than it is on the road.
- The roads are a bit bumpy, and there were a few small hills
- I purposefully stopped pedalling on a couple of the hills

[deVries]

Which specific controller/motor did you use for the video?

What specs do you get with this motor voltage? Top Speed level or 5% hills w/total weight? Wh on level at x-speed? Etc.

Thanks.

[adrian_sm]

ESC: Turnigy 85A
Motor: Turnigy Aerodrive SK3 - 6364-190kv
Battery: 5s5Ah 20C LiPo in 4p configuration
Top Speed Level: ~40 kph
5% Hill: No idea, but it is pretty much just a function of power so you can work it out
wh/km: Very dependent on the bike aero, and rolling resistance, more so than the drive. But given I do about 40kph, at 500w, that equals 12.5wh/km. But in reality I will get much better efficiency as the bike is really easy to pedal, so I use the assist a lot less than my hub motor bike.

More info here.

- Adrian

[adrian_sm]

Video of the same mount on a hub motor bike, to compare noise.

On the bike the hub motor is very quiet, but the GoPro/mount picks up the noises more.

[adrian_sm]

[EDIT] Removed. Posted to the wrong thread.

[adrian_sm]

[EDIT] Removed. Posted to the wrong thread.

[adrian_sm]

[EDIT] Removed. Posted to the wrong thread.

[liteCycles]

Adrian,

Can the commuter booster be mounted on a frame that has the Front Derailleur Cable directly behind the seat post?

Is it possible to drill a hole through the mounting block, then thread the derailleur cable through? Would not want to compromise the strength of the mounting block or hit the internal return spring.

cross_pro_ti_xi_2100.jpg (118.7 KiB) Viewed 546 times

[adrian_sm]

Yep definitely possible. But since those cable mounts are not in identical spots on all bikes I did not add the clearance hole to every unit.

I'l PM you a diagram that should help show you where it is safe to cut into the block.

BTW I would just make the hole actually break through into the seat tube hle. This way you don't have to thread the cable through.

- Adrian

[adrian_sm]

Just found out that one of the Alpha units has been resold for a profit, after a bike shop called me up to help trouble shoot, and let me know how much their customer paid for it.

Funny.

[jana]

When will these be available for sale again?

[adrian_sm]

It will be a month or more.

Family life has taken over development time, and I am about to go overseas for a short trip. I learnt a lot from the last round, and I really want to make the next batch a lot simpler to use and install.
Less things t get wrong when setting it up, and easier to use once installed. All these changes are on the electronics side BTW.

Currently this means:
- removing the display, but make it available as an upgrade option
- introducing a normal twist throttle option
- integrating the brain box functions into the controller
- mounting the new controller on the seat post, or front of drive mounting bracket
- soft on/off switch which allows the controller to turn itself off, which will add another layer of protection for the batteries from over-discharging.

This will effectively result in a dedicated Commuter Booster controller. That just has battery, motor, wheel sensor and throttle inputs and outputs.
It will still be fully programmable but this will be done by connecting it to a PC via a USB cable.

Then I will likely sell it as a complete kit minus battery system.

- Adrian

[Degull]

I have one from the last batch that I have not had a chance to play with. It is brand new never installed, just looked at. If anyone wants one, shoot me a PM, you can have it for what I paid for it (I think is was approx. $180).

[adrian_sm]

I assume that is just the drive unit, and not the brain box.

BTW degull, do you think it would be a better approach for me to only sell the commuter booster with the controller and motor etc. Meaning all you would have had to do is source a battery to get it running? Or did something else stop you from installing it? It will end up being more expensive for people than sourcing all the parts themselves (as my volumes are too small to get a discount) but it would be much simpler for people.

- Adrian