Using RC motors on E-bikes [Archive]

[nemo]

Do you have a picture of this freewheel ? I'm interest to see it. Thank You

 

[John in CR]

I did something similar with a freewheel. No way was I paying $100 for a rear bike hub threaded on both sides, so I took 2 regular cheap rear hubs and cut them each in half. Then I welded the 2 halves with threads together, giving a hub threaded on both sides. Now the normal thread would be fine for a screw on brake disc, but for a sprocket would unscrew. I just put epoxy on the threads and screwed it on tight. It never budged and gives me a freewheeling sprocket on the left side. That may not stand up to some of these really powerful RC motors, but I'm sure there is some adhesive that would make it permanent. I didn't want to tack weld it out of concern it would damage the freewheel grease or interior parts.

John

 

[Miles]

belt pulleys and belts

where to get those ?

aluminum and plastic reenforced,
good source sdp-si.com but they don't list GT2 belts (timeing belts, poly chain gates)

need to get to 49:1 ratio, 2x3x3x2.77 = 49:1

on the last gear, thinking to use a flip flop hub ,... sealed bearings,
but how to mount a belt pulley ? cound not find a thread cutter for bmx hub 1.375 die ,

Belts and Pulleys you can get from SDP, but only to 5M.What pitch do you want? Polychain is expensive...Why 49:1.......?

Flip flop hub isn't ideal as both threads are right-handed.... you can use anaerobic adhesive to bond the sprocket on but it's better to use a bi-drive such as http://www.profileracing.com/estore2/index.php5?productid=16 Screw on a sprocket or LH freewheel and fix the pulley to that..

 

[docnjoj]

Do you have a picture of this freewheel ? I'm interest to see it. Thank You

http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=4331
otherDoc

 

[rschultz101]

just found an bmx disc adapter for flip flop hub,
http://www.bikeworldusa.us/Atom-Lab-Disc-Brake-Adapter/M/B001DCYS9I.htm?utm_campaign=froogle&utm_medium=organic&utm_source=froogle

but think, by the time of adding the dapter, and figuring out the right size to bolt on a belt pulley,.... it be too wide, ...
the bmx hub is already 120mm, plus the nuts / axel, it won't fit between the cranks,... if I take the bmx hub, get a sealed one, get smaller spacers,...
that might work to get it down to 100mm befor axel/nuts,... bolt on a 15mm HTD belt pulley on the flange,... right size freewheel 18t, left side , guess 60+t pulley,..
that be the 4-stage,... side plates to mount, but now, everythink needs to fit inside those dimensions, including motor plus pulley, and axel load bearings for the motor,...
oops the the 49:1 was for an 2500rpm motor,... for outrunners,... 36v * 170kv, ~6000 rpm, need almost 100:1 ,... 3x3x3x3 4 stages be 81:1 ,...
6000 rpm / 81 = 74rpm at crank,... think 15mm wide 5mm HTD belts will do,... at $100 per stage +200 for side plates axels , bearings,... be $600 for the box
where can I find dimensions for the outrunners ,... aka, HXT 80-85-B 170Kv,... would that fit between 100mm,...

oh, the big wheel pulley idea, is not going to work, for most frames , due clearance issues

this gearbox thing is a major undertaking, ....
there is always the truck starter motor with worm gear drive,... but at 20 lbs+ + 20lbs mounting hardware, controller, + batterys, that's 80-100lbs + for a bike,...
not what I'am aiming for,... like to add only 10% weight from current rider + bike,... aka 30 + 180 = 210 so the additional stuff should be ideally only 21lbs extra,...
gearbox efficiency,... 100:1 aoutsch,... 3 belts + 1 chain, plus 8-12 bearings, tensioning,... did somebody mention, once the belts are tight, the motor got hotter ,...

dynometer,... pedelmeter ,... thinking one of those exersize backwheel trainers, where you can adjust how hard you'd pedal, then have the motor drive it and figure out how much batteries you'd need,... there is one of those power metters for a car, where it measures the acceleration , don't know how accurate that would be for a bicycle/ mtb to measure the watts/joules ,...
just brain stroming , appreciate your input

 

[lawsonuw]

I've found that gearing the motor's free speed to match the fastest the rider can pedal for a minute or two works quite well. (see my Linear build report linked in my signature) Also, spur gears are only noisy if the mesh is off and they don't have enough teeth. (a 10 tooth pinion is too small, 16 or 20 teeth will be much quieter) Helical gears are an option too, SDP-SI.com has some 45 degree helix angle gears that would work well as a first stage.

Some other gear suppliers
http://www.qtcgears.com/RFQ/default2.asp (has some nice helical and helical bevel gear choices)
http://www.pic-design.com/
http://www.bostongear.com/
http://www.martinsprocket.com/
http://www.wmberg.com/ (mostly smaller stuff)
http://www.sdp-si.com/ (generally the metric gears are better sizes for power transmission)
(Also, the .pdf version of the SDP-SI catalog has a LARGE section on how to properly size gears and belts. Worth reading)

I've been tempted to make something similar to the "cyclo" gearboxes http://www.smcyclo.com/ makes. Unfortunately I don't have ready access to a CNC machine that could cut the rotor. A "cyclo" gearbox can go 20:1 or more in a single stage with high efficiency.

Regarding threads, for the 1.375x24tpi "standard" thread and the 30mm by 1mm/thread BMX (I'm pretty sure that's what the BMX thread is) the threads will need to be custom cut. It's not to hard to do on a lathe with a thread cutting drive. A CNC mill or lathe can also cut odd size threads. (I've made two "standard" freewheel adapters so far) http://www.staton-inc.com/ also sells "standard" freewheel adapters that fit on a 5/8in keyed shaft. (wish they made BMX thread adapters too!)

Marty

 

[dirty_d]

hmm, putting that threaded disk brake deal on the other side of the hub woul work for brakes since its being tightened when you brake. but if you put a sprocket on it will produce torque in the opposite direction and loosen it, maybe you can just weld it so it cant come off.

 

[Dee Jay]

How 'bout them beans? A Sanyo tranny and RC motor combo!

http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=2744

We have truck-loads of these hubs here, many of them just abandoned in the streets, Woo woo! I found an abandoned one just this week.

I never seriously considered using this hub because I didn't want to deal the built-in electronics I knew nothing about.

Hell, I can just tear all of that out and install the ESC and I'd still have plenty for room to put my weed in there, :wink:

-Plenty of space for cooling fans and/or heat fins on the gears

-Belt driven so it should be silent.

-Built-in One way Roller Clutch

-20" wheel will help reduce motor RPM...

Would need to secure non-rotating side to the frame to act as a torque-arm.

Last gear need to be bigger, I think.

I may not even need to use an RC motor, maybe I can rewind the existing motor for more speed!

Hey Rick (aka rkosiorek), did you need special tools when you took it apart? And what's the width of this hub? I wonder if I can fit one in my Revive at 135mm.

 

[Miles]

Info on the new 55mm class Scorpion motors:

"The new 55mm motors are still in development, and most likely, will not be available for a couple more months.

There will be 3 different sizes in the 55mm line-up, the 5525, 5535 and 5545.

The 5525 motors.... will be available in 3 Kv values: 170, 195 and 225. These motors will weigh about 24 ounces, and will be able to handle around 3000 watts of power.

The 5535 motors..... will be available in 2 Kv values, 160 and 190. These motors will weigh about 29 ounces, and will handle up to 4000 watts of power.

The 5545 motors..... will be available in 2 Kv values, 150 and 180. These motors will weigh about 37 ounces, and will handle up to 5000 watts of power."

Ref: http://www.rcgroups.com/forums/showpost.php?p=10539557&postcount=3738

 

[johnrobholmes]

Thanks for the post Miles. You can bet I will have a few of the scorpion motors. I can tell you right now that they can't be switched very fast, any more than 12k PWM and they get noisy and hot.



Edit: Who am I kidding, I talk to Lucien about once a week and know more about the 55 series than he posted :lol:

 

[Miles]

Thanks for the post Miles. You can bet I will have a few of the scorpion motors. I can tell you right now that they can't be switched very fast, any more than 12k PWM and they get noisy and hot.
Edit: Who am I kidding, I talk to Lucien about once a week and know more about the 55 series than he posted :lol:

Have you had some samples/prototypes to play with?

Any info you can divulge on the new controllers?

 

[johnrobholmes]

I haven't gotten a proto of the 55 series yet, but it won't be anything new or fantastic. Just a big dLRK motor with decent winding. Great stator laminations, strong magnets, but the wire could be packed in a bit tighter on most of the builds. Nothing new for a production motor though, winding them fast is much easier with thin multi strand instead of one thick ass wire. I don't know if they have settled on final design, but it will most likely have the version three fan on the end like this:

As for the controllers, there has been no new information for a while. Lucien isn't involved with the engineering of them, and frankly I have not been impressed with them for ground use. The back EMF detection is not precise enough or not fast enough to work well for Bike use IMO. They may work decent enough for ebikes with weaker hub motors, but for RC motor use they are not very solid on commutation synch.

 

[Miles]

Great stator laminations, strong magnets, but the wire could be packed in a bit tighter on most of the builds. Nothing new for a production motor though, winding them fast is much easier with thin multi strand instead of one thick ass wire.

I guess rolling our own from the kits is the way to get the most out of them, as usual..

 

[johnrobholmes]

Yep, and the kits will probably be available too. If they are not, I could get some made.

 

[Dee Jay]

And what's the width of this hub? I wonder if I can fit one in my Revive at 135mm

Woops!

yes it can be fitted to any frame with wide enough rear dropouts. ie. 135~145 mm. on the freewheel side the spacing can be adjusted using the 2 thin nuts on the axle. just remove the freewheel to see these nuts.

rick

YAY
YAY
YAY!

I'm going to inspect the abandoned bike and take some pics. If I don't see a registration sticker (yes, we register bicycles here ) I may just take the motor ASAP. Can hardly wait!



J

EDIT: http://endless-sphere.com/forums/viewtopic.php?f=3&t=3035&p=97012&sid=3453f366a575cc6a4bd68f71c184c8ab#p97012

Oh yeah... KnomSayin'? 8)

 

[swbluto]

http://www.aero-model.com/motordetails.aspx?series=A100/200&style=6

Does anybody think this motor would be good? It claims it handles upto 15,000 watts but I would guess you could probably, as a lower-bound, extract 10,000 useful watts. According to http://www.kreuzotter.de/english/espeed.htm, that's about 63 MPH. Yeah, you'd probably have to use motorcycle sprockets and chains on the other side of the bike.

 

[RLT]

http://www.aero-model.com/motordetails.aspx?series=A100/200&style=6
Does anybody think this motor would be good? .......

Pretty impressive motor. But at $1,100 I"ll sure not be the one to find out if it works... You can buy TWO 530Xs or 2 ETEK s for that.

 

[swbluto]

http://www.aero-model.com/motordetails.aspx?series=A100/200&style=6
Does anybody think this motor would be good? .......

Pretty impressive motor. But at $1,100 I"ll sure not be the one to find out if it works... You can buy TWO 530Xs or 2 ETEK s for that.

But you can't get upto 63 mph on a normal bike... while only carrying 5 lbs. of motor. The former could do... what... 7000-8000 useful watts together? The latter could do 15,000 "input power"(useful power at maybe the same lower bound) or possibly higher, so that sounds competitive, but it wouldn't weigh 5 lbs. According to http://www.robotmarketplace.com/marketplace_etek.html, two would weigh 56 lbs.

But at those speeds, you probably already have a heavy burly ride with the batteries and all. And there might be differences in reliability between the two, with e-tek possibly being heavier duty.

(No, wait. Assuming 5C batteries... 15KW/5C = 3 KWH. 3KWH*25lbs/1KWH = 75 lbs. Okay, that's heavy.)

 

[recumpence]

My $1000 plettenberg motor pushes my bike at 40mph without even breaking a sweat and it is alot lighter (2 pounds). It runs nice and cool and only pulls a bit over 1,000 watts doing it. I could gear up to 60mph without much problem. But, anything over 45mph gets pretty scary on a bike.

Matt

 

[swbluto]

:lol:

40 mph at a little over 1000 watts is pretty impressive, though as I'm only going 26 mph at 900 watts on my c'lyte 407 where it's supposed to be ~75% efficient. That might be aided by your relatively small frontal area for air drag(my calculations were based on a mountain-bike according to http://www.kreuzotter.de/english/espeed.htm), where most energy is consumed. Do you have a thread-topic/blog where you detailed your build with the motor/gears/etc. as I'm fairly interested in it? I could trek through this thread but I'm still back on page 11 and that was >7 days ago, so I naturally don't remember many details.

Not to mention that doubling the power on a vehicle doesn't even come close to doubling the top speed.

True. kv^3 = P. v = (P/k)^(1/3). At "high Reynolds numbers", which we are considering here. So, basically, twice the power means 2 to the cubic root times the top speed. Or... ~1.26 the top speed.

 

[Storm]

Beaware it is almost half as long as this thead itself:

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=3904

And:

http://www.recumbents.com/WISIL/shumaker/default.htm

 

[MitchJi]

Hi,

Any advice on these?:
plettenberg Xtra 30:
http://www.plettenberg-motoren.com/UK/Motoren/aussen/xtra30/Luftschrauben.htm
http://www.icare-rc.com/plettenberg_xtra30.htm

Or:
Xtra 30 Evo:
http://www.plettenberg-motoren.com/UK/Motoren/aussen/xtra30evo/Motor.htm
http://www.icare-rc.com/plettenberg.htm

Xtra 30-Evo, high performance version of this popular outrunner now available. Up to 3.5kW of pure power. Will fly scale aircraft up to 20lbs

The Xtra 30 Evo is an improved version of the Xtra 30. It is the model just below the Terminator Matt used.

I am seriously considering getting an Xtra 30 ASAP because right now it is available for $275.00:
http://www.icare-rc.com/specials.htm
Xtra 30-10 (Normal Price 479.00) Clearance Special 275.00

http://www.icare-rc.com/plettenberg_pricelist.htm
The Xtra 30 Evo is:
Xtra 30-10 Evo "Normal Price" 626.00 "Sale" 515.00

Compared here (probably not an unbiased review). Reviewed by:

Adam Glatt
Team F3A Canada
Team Plettenberg

:
http://www.rcgroups.com/forums/showthread.php?t=532405

Is the Xtra 30 a good choice? Should I (we) jump on the $275 price? Would it be a better idea to pay 515.00 for the EVO? Is that overkill? Of course I would like good performance but my main concern is I live in a hilly area and don't want to burn out a motor.

My next step is to check the link Miles recommended (I've been a little under the weather lately) but any advice would really be appreciated!

Thanks!

Mitch

 

[recumpence]

The only negative with those motors is the lack of an output shaft. They are designed with a prop adaptor on the end of the can, but not an output shaft.

Matt

 

[voicecoils]

The only negative with those motors is the lack of an output shaft. They are designed with a prop adaptor on the end of the can, but not an output shaft.

Matt

So, a chainring or a pulley would need to be bolted straight to the motor face?

Which bits of the motor spin, for the curiosity of us non-RC folk?

 

[Miles]

Which bits of the motor spin, for the curiosity of us non-RC folk?

All of the motor case apart from the end where the wires exit. For use on bikes, you need an accessible shaft at this non-rotating end of the motor... as in this photo that John posted earlier: