I don't like hub motors - (crappy ones)

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swbluto

10 TW
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May 30, 2008
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I've had my RC motor + controller and I must say it's a god send! The only thing that limits it from going much faster is the current I'm limiting it to. My 407 hub motor - What's limiting it top speed? Oh, that's right, the voltage. As you might know, increasing the voltage is not as easy or as cheap(or, in my case, not nearly as effective) as increasing a programmable current limit. And, and... get this! My motor could propel me up a hill at 30 mph without even making me help at all - the only thing standing in the way is the current limit! What's limiting the 407 from going up a hill at 30 mph unassisted? Oh, that's right, reality.

Another thing I don't like about cheapalyte hub motors is their shoddy aluminum casting. To quite a few, it means having their gears shearing off the threads; To me, it means a broken flange! Have I had to deal with this with on an R/C motor? Nope. But, I'm probably speaking prematurely as the cheap R/C motor I have might(probably) eventually come down with other quality control or reliability issues, but it seems those are more readily fixable than the aluminum problems some crystalyte owners have experienced.
 
can you take a picture of what you are talking about? I don't know what an RC motor is. Also, how fast can you go on 24v on the flat?
 
morph999 said:
can you take a picture of what you are talking about? I don't know what an RC motor is. Also, how fast can you go on 24v on the flat?
Click to expand...

Go to hobbycity.com and click on "Outrunner motors". You'll find a ton of these special R/C motors. The problem they have with bicycles is mounting the motor and drive system to bike, so it's more difficult to set up, but it's soooo much sweeter than a fixed hub. If you get the right batteries(I.e., those that can supply the necessary current) and pick the right gear ratio, you could get near 35 mph off of 24 volts on flat land. Typical "fast" hub motors? Maybe 17 mph. But they definitely don't compare when you start climbing hills! That fast hub motor starts to become a weakling up a hill but the R/C motor will be happily chugging along at greater than 15 mph at 24 volts(Given you set the current limit high enough).

Also, there's a "Non hub-motor" section on Endless Sphere, you might check it out some time.
 
swbluto,

Are you still running a hub motor on your bike, and RC on your scooter?

If so, when will see your RC bike build???? :D

(or have I missed some posts?)
 
It's all on my scooter. I admit, I haven't gone through the frustration of mounting an RC motor to a bike(But it did take a few reworks to mount it to the scooter! But, luckily, the "system" was already in place so it was pretty straightforward in what needed to be done) and mounting the necessary gearing system, but those are setup costs: once you're done, you're done!

Right now, I'm just seriously thinking about selling my hub motors and going to all R/C motors as I seem to be getting pretty annoyed by their crappy build quality and I just don't want to invest any more money in what I think is an inferior technology(They are more stealthy, however and a little quieter.). If you're using a123s, you should *definitely* try out R/C motors and take advantage of the power of your a123s! If you're using low-C batteries like Pings, you probably won't notice much difference assuming you use an appropriate current limiter(If you don't, I can guarantee your Ping's BMS will cut out!). With the a123+ping pack hybrid(I'm planning on building one), R/C motors are definitely the way to go whereas I'm just seeing little to no way to take advantage of the potential performance benefits of that on my hub motor. Maybe when going up hills and accelerating from a stop at lower speeds(Which would require modification of my controller or buying a new one - Not something I'm looking forward to doing if I'm moving away from hub motors), but that wouldn't get me anywhere near as good as a fine-tuned R/C motor system would be.
 
that one guy on youtube was using some kind of motor, maybe a cyclone and I posted it on here and most people said that it was inferior to hubs because I think the motor would overheat. No overheating problems?
 
For my boring 20 mph, at boring 36v, drawing a boring 12 amps, my inferior front hub motor gets me to work day after day.

It just depends on what you want I to do. I agree though, that taking a hub motor and pushing it way beyond it's design voltage is not the best approach to speed. I keep telling noobs, if what you want is going to cost 3-4 thou, why not just convert a motorcycle? Not an rc motor, but the same concept, get a good motor and chain drive it.
 
Well.... i've thoughrolly tested everything hub motor.. I've done a 500w cyclone ( hated that thing.. ) And i expect my 2 stage Astro powered beast to arrive at my doorstep this week .. so i shall soon find out.

Hub motors, for legal 500w, easy to install, maintenance free, ( weather resistant ? ), installed by the average joe with a few allen keys and an adjustable wrengh on most bicycles... hard to beat.

Higher perfromance Hub motors ?.. yes.. it's possible but it involves small diameter wheels, and high voltage ( to make up for the wheel diameter reduction ). An X5304 in a 20" wheel with 48v to 72v 40 amps won't bog down on hills..

Watt for Watt... don't matter what voltage you run if you put into consideration the system as a whole.. fine.. you can do 40 mph on 24v with an RC motor..but at 100 amps. :wink:
 
I ain't got the energy for this - sure that's not Randy lurking in the background? :|

DK
 
swbluto said:
I've had my RC motor + controller and I must say it's a god send! The only thing that limits it from going much faster is the current I'm limiting it to. My 407 hub motor - What's limiting it top speed? Oh, that's right, the voltage. As you might know, increasing the voltage is not as easy or as cheap(or, in my case, not nearly as effective) as increasing a programmable current limit. And, and... get this! My motor could propel me up a hill at 30 mph without even making me help at all - the only thing standing in the way is the current limit! What's limiting the 407 from going up a hill at 30 mph unassisted? Oh, that's right, reality.Another thing I don't like about cheapalyte hub motors is their shoddy aluminum casting. To quite a few, it means having their gears shearing off the threads; To me, it means a broken flange! Have I had to deal with this with on an R/C motor? Nope. But blah blah nlah blah blah blah blah blah blah blah blah blah nlah blah blah blah blah blah blah blah blah blah nlah blah blah blah blah blah blah blah blah blah nlah blah blah blah blah blah blah blah.
Click to expand...


Oh Yeah? Well My Hub motor just banged your RC motor's Mom. :p
 
Those motors are for toys. How long do the bearings last if they all seem to spin at 3000rpm+ Hub motor bearings typically last 10000km before the bearings need replacing. If I spent as much time as you on a scooter drivetrain I would expect it to do a lot better than 30mph uphill. That is the same as an x5 at 60v on a much heavier bike frame.
 
Well, I'm also conscious of cost. The controller to drive an X5 is going to be comparably expensive as the controller to drive a hungry RC motor. So, now we're onto hub motors. What's the X5 going to cost? Oh, that's right, a cool five hundred dollars, extra 30 pounds to your bike's back and a dangerously high voltage needed to get high speed and reasonable unassisted speeds up hills. What does an RC motor cost? Maybe 200 dollars(bearing replacement and additional gluing included in the figure :wink: ) and maybe 4 pounds to the bike. That's quite a difference! To be honest, you'll also need to figure in extra drive train costs, unless you're piggybacking, and I'm guessing you can get that for under $200 just by looking at some of the enterprising efforts in the non-hub-motor section, so maybe $400 in total or less. Given the lack of need to run at high voltages to get reasonable speeds up/through anything, that also improves safety(And for a123s, you can also readily run in their original configuration).

Also, the cooling of outrunner motors are generally superior to hub motors as they have an open design and some are designed to 'forcibly air cool' and the magnets are separate from the coils, so you can pump a bit more power through them to get the same temperature rise. It's also possible to increase cooling if needed, but it seems people generally haven't needed that except for those who seem to run their e-bikes at >50 mph.

Sure, hub motors are easy to set up, but they have their limitations and extra costs. I sure know that a hub motor certainly wouldn't be anywhere nearly as powerful at the size of vehicles that my scooter belongs to.

So, if you want power and non-aluminum strength and ease of set up, get the X5. If you want power, safety, low weight and are the slightest bit mechanically inclined and have an ounce of fortitude, I'd highly suggest looking at R/C motors. For smaller vehicles than bikes, hub motors just can't even begin to compete(assuming you can mount the R/C motor).
 
huskydave said:
That is the same as an x5 at 60v on a much heavier bike frame.
Click to expand...

I declare... fact check! I actually can't fact check that as my current computer can't run the e-bike simulator I programmed(see in the tag-line), but let's say 7% hill and 290 pounds(190 pound person+50 pound bike+30 pound motor+20 pound batteries) and than let's compare that to a 260 pound bike on a 7% hill with an optimized gear-train. How do the speeds compare?
 
performance is bike to bike. 5305 with a123s 50a controller and 60v will do 30mph on a medium grade. I have nothing against using toy airplane motors but it seems like a lot of work and less reliable ie high rpm motor + more moving parts = less reliable everything has pros and cons but an rc setup is needlessly complicated.
 
Ypedal said:
you can do 40 mph on 24v with an RC motor..but at 100 amps. :wink:
Click to expand...

And that's no problem for a Ping! Just rewire a 48V20Ah(you'll need the capacity anyways at insane power levels) into 24V40AH and 100 amps is only 2.5C. Just replace a few bad cells now and then when they crop up and you'll be fine. Or, alternatively get 2 24V20Ah packs or 3 or so. :lol:

Honestly, if you want range and available power on the cheap, I'd suggest paralleling pings and a123s. BUT, you have to pick the right configuration to ensure you don't hurt the Pings and add on some electronics to protect things.
 
are those motors meant to be run continuously or are they supposed to be cooled down after 15 minutes.
 
I don't know. But it does seem reasonable for you to suspect that something designed for an RC aircraft would have similar limitations when directly applied to e-bikes, but the general saying with nearly anything electronic/mechanic, "you can run anything as long as you want as long as you have sufficient cooling". That said, I don't think my motor would have to be actively cooled at 1300 W continuously(As it's only merely warm running at 700 W for 20 minutes or so at 70% efficiency) and it could be ran as long as you wanted. Of course, you might want to improve the bearings beforehand as not all bearings are created equal. I've heard, in particular, that ceramic bearings have much less heating issues at a given RPM but I haven't tried replacing anything, yet.
 
come up with a frame that has a non-jerryrigged mounting system for r/c motors, and come up with a good way to weatherproof 'em and then i'll be interested.

as it is now my 407/pedal-first/48V 12Ah LiFePO4/CA system works day in, day out, in sunshine and in torrential rains even when left outside for 30 hours when i'm on call. i'll trade performance for reliability any day, since going to work is not optional.
 
swbluto, the e-bike industry needs enthusiastic early-adopters like you. I have been following the non-hub section RC posts with interest, and eventually I may buy the parts for the reasons you mention (a year from now?), but...

If my wife wanted an electric kit installed on her bike this week, I would just buy the hub-motor from ampedbikes.com.

Keep experimenting, and post pics with a description of what you liked/didn't like.
 
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