Grinhill's Medium-power RC-Motor Hardtail build

[swbluto]

Great project. I'm particularly interested in the spoke-mounted pulley from Golden Eagle. Does it compromise the wheels in any way? Looks a little scary to me...

Dang, $300 just for the mounting kit? It looks like a bunch of plastic and metal...

Given how common gas kits are for the bicycle, surely there are cheaper places to get a spoke-mounted pulley? It seems the one thing that'd be superbly helpful in adapting an R/C motor would be the spoke-mounted pulley, mainly, but also a drive pulley and motor mount would be helpful. In my opinion, though, those can be easily enough ordered and constructed. Wood+rear-rack = easy!

 

[swbluto]

Anyone else had problems with these ESCs?

I haven't had a HobbyCity ESC, but it seems recumpence has seen many others who've had syncing problems or other problems with HobbyCity's ESCs. It seems like some of the newer ones might be better, but they seem to be approaching the cost of a Castle ESC as might be expected. :lol:

 

[Miles]

Great project. I'm particularly interested in the spoke-mounted pulley from Golden Eagle. Does it compromise the wheels in any way? Looks a little scary to me...

Dang, $300 just for the mounting kit? It looks like a bunch of plastic and metal...

Given how common gas kits are for the bicycle, surely there are cheaper places to get a spoke-mounted pulley? It seems the one thing that'd be superbly helpful in adapting an R/C motor would be the spoke-mounted pulley, mainly, but also a drive pulley and motor mount would be helpful. In my opinion, though, those can be easily enough ordered and constructed. Wood+rear-rack = easy!

The pulley is available separately, for $40 plus $10 for shipping.
http://www.bikeengines.com/orderpage2.htm

 

[ktronik]

Just want to thank Grinhill for poping over to my work, for me to have a look/go... Man! having only ridden hub motors this RC tech is great!! its got bags of pull off the mark!! & goes really fast for the size of everything...& the battery fits in a water bottle...crazy stuff...

thanks Grinhill!! today I wore that R/C EV grin...

Best

Ktronik

 

[Grinhill]

No worries, mate.

It's good to know someone who works at the LBS (local bike shop) and actually has an interest in e-bikes. You're definitely in the minority there.

 

[swbluto]

The pulley is available separately, for $40 plus $10 for shipping.
http://www.bikeengines.com/orderpage2.htm

That's pure awesomeness.

Grinhill, do you know what the pitch and width of the drive pulley is? Is it like... 5-15m HTD (Is that the correct phrasing)?

 

[spinningmagnets]

Great work, Grinhill, very inspiring! concerning the wheel pulley option for our budget-minded friends...

The original "Peltzer" version 1.0 used a 20" rim. He ended up being unhappy with this, but this was years ago, before RC motors became an option and HTD belts became better-known. Motor is a 24V 3,000-RPM Scott one-HP from an EBAY floor scrubber. When not being used as a short range hot-rod bike engine, it can be used to crush your enemies.

Eric said this does 30 MPH on the flats and 20 MPH on a steep uphill. Final version ended up with two-stage drive. Rubber toothed-belt primary and chain secondary to eliminate wet weather pulley slippage. Single-stage chain version was too noisy.

For stealth, how about combining this with a (ahem..cough, cough) rear Bafang "drum brake" in-between two pannier-bags? Everyone will of course "see" the bright shiney RC motor and belt...("drum brake" only used on hills?) the RC motor should provide excellent range on the flats, along with its other obvious benefits.

 

[swbluto]

Spinningmagnets, do you have a build page of some sort for this bike? I'm very curious where you obtained the spoke-mounted pulley and other needed equipment.

The beauty of the "wheel" mounting type of method is that it seems that it could be relatively easy to adapt to dual suspension bikes without incurring suspension-based drive losses or too many other complications. It also seems that you might need to lose the back v-brakes if you want to mount on the back-brake posts, but this doesn't seem to be a type of theoretical necessity.

 

[Miles]

Grinhill, do you know what the pitch and width of the drive pulley is? Is it like... 5-15m HTD (Is that the correct phrasing)?

Looks like 5mm pitch 9mm wide (XXX-5M-9 HTD) belt. Pulley will be wider, of course.

 

[Grinhill]

Looks like 5mm pitch 9mm wide (XXX-5M-9 HTD) belt. Pulley will be wider, of course.

Yep, spot on Miles. The pulley width is around 13mm between the flanges, which is specifically designed for the 9mm width belt. It seems to self-centre quite well anyway.

 

[spinningmagnets]

swbluto, here's the Peltzer build-site and his final version 2-stage. He only required short range, but had steep hills and wanted high power from 24V.

http://www.electricycle.com/

Grinhill, if one of these RC motors was mounted like yours but on a rear suspension bike, could it be better or worse for the motor running over a pothole? hardtail, or sprung?

The recent projects with an RC 2-stage drive seem more appropriate for a BB "Cyclone" style attachment (to me), but your single stage seems a good fit for a rear suspension, and unlike left-spocket-drives, it still allows a disc brake for those who want it...

 

[Grinhill]

I think the beauty of a 400g motor is that there will be much less force on the mounting & frame when you hit the proverbial pothole than if you had a Scott motor mounted there.

The hardtail vs suspended will probably not make much difference.

See Luke's twin-motor monster, those motors are double the weight of mine, although they are mounted lower down.
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=8347

 

[spinningmagnets]

Grinhill, I want to thank you for posting all of this information!

"...Top speed is 44 km/h (27 MPH) on the flat, and if I pedal as well I can maintain 35 km/h (21 MPH) up a 10% grade, pulling 45A at 22V (990 Watts!)..."

Most RC builds are focusing on an upscale high-performance set-up, but after converting units, I am even more interested. I am impressed with the two-stage drive on Ypedal's build, but its $150 now (and easily worth $250 retail) and its capabilities exceed my needs. This set-up of yours is looking like its perfect for what I want.

If you were building this bike again from scratch, would you do it exactly the same, now that you've ridden it for a while? Have you found alternative parts options that may have been better?

 

[Grinhill]

Spinningmagnets:

If you were building this bike again from scratch, would you do it exactly the same, now that you've ridden it for a while? Have you found alternative parts options that may have been better?

I'm still sketching away at new ideas, but I can't say I've come up with anything much better. The weak link is still the one-way bearing setup.

I have considered going to the larger motor size, which would give a few advantages for not much extra cost:
- lower Kv allows use of 20-tooth pulley for same speed
- lower motor temp up hills
- 10mm shaft allows larger size one-way bearing with higher torque rating, should last longer.

As always, there is a downside, which would be boring out the pulley to a larger diameter to suit the one-way bearing. Whether you use a drill press or a lathe, it's still difficult to clamp the pulley effectively, without damaging the flanges. It would be great to be able to avoid this machining step.

I think the shafts of these motors still aren't hard enough to use with the one-way bearings (since they roll directly on the shaft). I have found a hardened 1/2 inch shaft (2 inches long) in my garage which may be more suitable. This then introduces another problem - support bearings would be required, and also a method of drive coupling from the motor to the shaft. I have also given this some consideration, and one idea is to cut a slot in the hardened shaft (say 5mm wide) then grind flats on the motor shaft so they can mate together.

All of a sudden, the simplicity of the system is gone. Matt's drive system is looking very good.

 

[swbluto]

You don't really need one way bearings though, do you? It seems like detaching the motor to the wheel would be as easy as removing the belt when you don't want to use it. In your situation, though, it doesn't seem like you have timing pulleys where you can just slide the belt off, so you'd probably have to detach the motor pulley. Hmmm... I have a better idea! Make the motor or motor mount adjustable by some fashion, and just "bring it down" when you need to to remove the belt.

 

[Grinhill]

Do you mean like a belt-tensioning arrangement, say a lever or some sort of cam?

That may work, although with the large pulley, even when not under much tension, it has such a long contact area that it would probably still be trying to move the belt.

I would be interested to hear from anyone who has used a similar system without the one-way bearing, to see if the drag makes it too difficult to pedal when the motor isn't running.

 

[swbluto]

Do you mean like a belt-tensioning arrangement, say a lever or some sort of cam.

I wasn't thinking of that but that sounds like a good possibility!I say that because it seems "belt tensioners" are 'normal', I guess, since I've heard they stretch according to an experienced roboticist.

Anyways, on my electric scooter, the wheel's "timing pulley" doesn't have a ridge so it's possible to slide off the timing belt if needed. I typically carry several rubber-bands on me so I can take the belt off the timing pulley and attach it to the frame when I need to free the wheel from the motor when I want to ride "motor free"(i.e., when problems arise when I'm relatively far from home and the motor's resistance would seriously impede the ride). With proper alignment, I think something similar could be achieved with a bike and that's certainly better than what a hub motor has to offer!

 

[etard]

Is freewheeling really necessary? I can spin my Hacker motors with my hand, it doesn't seem like it would impede pedaling too much.

Also, I have some extra rc motors if you want to upgrade.

 

[bzhwindtalker]

I have a similar set-up but with a koll frame-mounted instead of vbrake monted.
no freewheeling. I can keep up withs friends with multi-speed (I used to ride the bike singlespeed) bikes with a dead battery.
but I am running a 1/10 gearing ( single stage belt) on a diferent kind of motor...may be different on rc's with higth gearing.
It works just ok like that but I'm a bit afraid of burning controler or batts on downhills....



get fun

 

[Joepostal]

I am waiting for parts to copy your design Grinhill. I will be hard mounting the pulley to the motor and I will probably use a belt tensioner to tension the belt. I figure I could just remove the belt from the motor and place it on the tensioner when I run dead. Still I won't have the parts for a month or the build done for a week or two after that

I will update here when I know how much the motor tows down the pedals...

I was looking at a 10mm inner and 12mm outer sprague but I couldn't find one in case it doesn't work hard mounted.

 

[Grinhill]

I have a follow-up to a posting by gwhy on the Castle Controller thread:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=7504&start=119

Last week I experimented with ESC settings (Turnigy 80A) as suggested by gwhy. I changed the start setting from VERY SOFT to SOFT, and I think it has definitely improved the ability to stay in sync. It is perhaps a whisker more "jittery" when starting, but since I always pedal-start this isn't a problem. NORMAL start was a bit too rough, and was no better at staying in sync at higher speeds.

I also tried different timing settings, and will stick with LOW as it is the best.

 

[Joepostal]

Hey Grin

Where did you get the fan for your motor? I have an old broken drill I was thinking I would tear apart.

MMM HOCKEY
Joe

 

[gwhy!]

I have a follow-up to a posting by gwhy on the Castle Controller thread:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=7504&start=119

Last week I experimented with ESC settings (Turnigy 80A) as suggested by gwhy. I changed the start setting from VERY SOFT to SOFT, and I think it has definitely improved the ability to stay in sync. It is perhaps a whisker more "jittery" when starting, but since I always pedal-start this isn't a problem. NORMAL start was a bit too rough, and was no better at staying in sync at higher speeds.

I also tried different timing settings, and will stick with LOW as it is the best.

My other cheap controller arrived (mystery 100a) it was a lot cheaper than i first thought it was only uk £18.00 delivered, it is the same as my other no name controller that I paid uk £29.00 delivered except for the input caps are only rated at 25v instead of 35v. The programming is the same on both controllers, and they both work well with a larger heatsink installed, doubling up on the input wires and using the extra caps . I still haven't got round to putting one a bike yet ( not enough time in the day ) but getting really close now 8) . I still need to do more testing as regards the sync issues when it is on a bike ( dont see any probs at all when the controllers on the bench ) but I am sure that the sync problems can be overcome I just need to get some real life readings to be able to sort it out.

 

[matt_in_mtl]

Has anyone considered replacing the firmware on a cheap esc?? There are guys using these brushless controllers in quadrocopters, and they need i2c interfaces, and fast response, so some have bought cheap chinese esc's since it is simpler/cheaper than making your own, and replaced the firmware with open source modified code. Doing this may allow better design for ebike use, along with the possibility changing the interface to 0-5V to allow direct ebike throttle use.

Information on modifying a TowerPro ESC for i2c interface. Likely the higher current esc's are nearly identical (more FETS).
http://www.mikrokopter.de/ucwiki/en/TowerPro25A2Regler

online repository of BLDC firmware used in quadrocopters
http://svn.mikrokopter.de/mikrowebsvn/l ... rev=0&sc=0

Good general info:
http://mikrokopter.de/ucwiki/en/BrushlessCtrl

If someone has brought this up, forgive me. I just think that it would make an interesting jumping off point for hackers to get more out of these cheap esc's.

-Matt

 

[gwhy!]

Has anyone considered replacing the firmware on a cheap esc?? There are guys using these brushless controllers in quadrocopters, and they need i2c interfaces, and fast response, so some have bought cheap chinese esc's since it is simpler/cheaper than making your own, and replaced the firmware with open source modified code. Doing this may allow better design for ebike use, along with the possibility changing the interface to 0-5V to allow direct ebike throttle use.

Information on modifying a TowerPro ESC for i2c interface. Likely the higher current esc's are nearly identical (more FETS).
http://www.mikrokopter.de/ucwiki/en/TowerPro25A2Regler

online repository of BLDC firmware used in quadrocopters
http://svn.mikrokopter.de/mikrowebsvn/l ... rev=0&sc=0

Good general info:
http://mikrokopter.de/ucwiki/en/BrushlessCtrl

If someone has brought this up, forgive me. I just think that it would make an interesting jumping off point for hackers to get more out of these cheap esc's.

-Matt

Im Liking the sound of that , The cheap esc that im playing around with are ok'ish, they can handle the current and the heat as long as they are well heatsinked. since my last post i have been testing again and have found a few things that im not happy with and this is down to the firmware, I wish that the 2 cheapos I got were different ( they are different makes but they are the same and use the same firmware :? ) the problem Im having with them is starting up when a massive load is on the motor and I have done enough testing now to tell me its not a sync problem , once the motor is moving and above a preset level of rpm then there is nothing i can do to make it loose sync as long as the motor stays above that preset level of rpm's and I think its built into the firmware as away of protecting the esc, motor and drive train on a model that should prob never see 50A+ from a non running condition, I have been thinking along the lines of maybe a esc for a car or boat would be better suited for ev use as these are more likely to deliver a higher current from a non running condition. I think the CC controllers have much better firmware that enables them to start a lot harder.