If you took a Bafang or similar and rebuilt the motor part using the quality materials and construction that they use in RC motors (good iron, good magnets, good copper), you could no doubt greatly improve the efficiency.
Using RC motors on E-bikes [Archive]
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voicecoils
1 MW
fechter said:
I strongly agree with this. If the actual Bafang body was better made, I'd be interested in trying to stuff an RC motor inside. However with a cast casing (I'm assuming), questionable bearing quality, very thin hollow axle on RHS for wire outs, and nylon gears prone to "peanut butter" destruction, it's perhaps not the best starting point.
The basic design, dimensions and price of the Bafang however does make the conversion idea tempting.
Hey guys, random idea that just occurred to me... since we don't all have fancy 5-axis CNC machines, but we would still like to keep our little RC motors cool, we can use impellers designed to keep vacuum cleaner motors at operating temp. A wide variety is available on eBay. Just take a look at these search results. I asked a few sellers for diameters and am awaiting replies. Shouldn't be too hard to adapt most of these to RC motors.
That sounds like it might be a good idea, except I don't know enough about outrunners to know their particular weaknesses, so I don't "qualify" to "qualify" the idea, so to say. Sounds good, though!
Anyways, I was wondering... has the idea of smaller wheels been brought up? That'd reduce the gear ratio to something a bit more earthly, then the you can just attach directly from the motor sprocket to the wheel sprocket and get the ideal performance from a low Kv RC motor. I'd say such a wheel size would be around 6" to 12".
Anyways, I was wondering... has the idea of smaller wheels been brought up? That'd reduce the gear ratio to something a bit more earthly, then the you can just attach directly from the motor sprocket to the wheel sprocket and get the ideal performance from a low Kv RC motor. I'd say such a wheel size would be around 6" to 12".
Fumesucker
100 W
Hyperion 5045-18 outrunner on ebay for a decent price..
http://cgi.ebay.com/NEW-HYPERION-Z5...39:1|66:2|65:12|240:1318&_trksid=p3286.c0.m14
http://www.aircraft-world.com/prod_datasheets/hp/z50/z50all.htm
http://cgi.ebay.com/NEW-HYPERION-Z5...39:1|66:2|65:12|240:1318&_trksid=p3286.c0.m14
http://www.aircraft-world.com/prod_datasheets/hp/z50/z50all.htm
Fumesucker
100 W
johnrobholmes
10 MW
I have sold a lot of hyperion motors, and I can say that I was never very happy with the construction. Magnets are not glued properly, they would rub on the stator, and I saw way too many stators come unglued from the bearing tube. Not worth the retail cost at least.
HAL9000v2.0
10 kW
Slowly I am turning off the hub motors, they are just to heavy for off roar ride. Last night I spent 2 hours reading this interesting post and just got 1 idea. Will this work? On HXT outruner motor like this one --> http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=5139 I like to attach on the axle perforated disc and 3 opto sensors and run it with kelly brushless controller. I think gearing should be 1:16 for 26" wheel?
HAL9000v2.0
10 kW
they say "Resistance: 17ohm" ! Is that correct or it is more likely 17mOhm?
safe
1 GW
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Unite motors have about 0.3 ohms resistance which translates to 300 mOhms and I would figure all of these RC motors are better than the Unite motors.
Unite: 0.3 Ohms = 300 mOhms
RC: 0.017 Ohms = 17 mOhms
...the Unite has 17.6 times higher resistance than the RC motor.
(I'm definitely hoping to do this one day)
Unite: 0.3 Ohms = 300 mOhms
RC: 0.017 Ohms = 17 mOhms
...the Unite has 17.6 times higher resistance than the RC motor.
(I'm definitely hoping to do this one day)
etard
100 kW
What kind of setup are you running? That motor could be a lot of overkill for your application, If you plan on something lightweight, find an outrunner with an 8 or 10 mm shaft, and maybe go back to 250kv or even 350kv, and gear it down for the rpm. We are all used to huge motors, but properly geared rc motors can be quite small. Spend that same money on a higher quality smaller outrunner. Just watch one of these videos and you see the power from only a 3550kv motor!!
http://www.youtube.com/watch?v=lbHuGsJYeCw
http://www.youtube.com/watch?v=lbHuGsJYeCw
docnjoj
1 GW
I've been out of model aircraft for a while now, but I have NEVER seen anything like that heli fly! WOW!
otherDoc
otherDoc
recumpence
1 GW
HAL9000v2.0 said:
Those motors are huge and innexpensive. But, I would move you toward a higher quality, but a bit smaller, motor.
You get what you pay for. Unfortunately, I have seen some problems with those motors if pushed anywhere near their rated output.
Matt
HAL9000v2.0
10 kW
I plan to use it up to 3kw constantly. Can you recommend some other motor that can give 2,5 -3kw constant? What is the difference in torque? I choose this motor because it has biggest diameter and biggest shaft; although this is not an issue because shaft is standing and half of the housing rotates.
I think that motor is vastly over-rated. At 48 volts, my program predicts a maximum output power of around 1300 watts with the optimized setup. The motor is probably rated by its input power(which is always higher than its output power, so why not?), which can reach 135 amps*48v ~=6000-6500 watts at its stall current(with a 135 amp controller; 150 amps could go upto ~7000, but still have a ~1350 ouptut max), but the efficiency is so low at that point, you're not going to realize any significant amount back.
But, you know, properly geared, 1300 watts of output power can take you upwards of 35-40 mph on the flat. So it's not much to sneeze at. Properly geared, it could get you up a 10% road at 20-25 mph(Or more if you're under 250 pounds for total weight).
*EDIT*:
It appears I was under the assumption of .4 ohms for the battery's internal resistance. Decreasing that number to .2 can increase the maximum output power to around ~3000 watts and .1 to around ~4000 watts. So, nevermind, it's not *that* under-rated if you have the "right" batteries(Which you'd need for the current this motor demands.).
But, you know, properly geared, 1300 watts of output power can take you upwards of 35-40 mph on the flat. So it's not much to sneeze at. Properly geared, it could get you up a 10% road at 20-25 mph(Or more if you're under 250 pounds for total weight).
*EDIT*:
It appears I was under the assumption of .4 ohms for the battery's internal resistance. Decreasing that number to .2 can increase the maximum output power to around ~3000 watts and .1 to around ~4000 watts. So, nevermind, it's not *that* under-rated if you have the "right" batteries(Which you'd need for the current this motor demands.).
dontsendbubbamail
10 kW
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HAL9000v2.0 said:
I am using the 130 kv version of this motor and a 53-54. You can read about my experience with HobbyCity motors on my "Bubba's Experiment" thread. My experience says that their voltage ratings are over rated by about 12V and the bearings are junk. I think they are great for experimenting and jury is still out on how long they last. Using this motor constantly at 3kw would be a stretch and I would expect you to have heating problems.
Bubba
safe
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The RC motors just make me drool....
My advice would be to go ahead with this type of motor and then build yourself an Armature Current Limiting circuit that would either truly limit the Armature side (controller to motor) or the battery side (battery to controller) and then place a limit of about 1000W or 2000W so that it doesn't overheat. Without a good current limiting device you get all the heat.
Limit the current... protect the motor...
One of the these days I'm going to do this too...
My advice would be to go ahead with this type of motor and then build yourself an Armature Current Limiting circuit that would either truly limit the Armature side (controller to motor) or the battery side (battery to controller) and then place a limit of about 1000W or 2000W so that it doesn't overheat. Without a good current limiting device you get all the heat.
Limit the current... protect the motor...
One of the these days I'm going to do this too...
Tom Tom
100 W
What do you guys think about the astroflight brushless motors?
http://www.astroflight.com/pdfs/3210.pdf
http://www.astroflight.com/pdfs/3210.pdf
Tom Tom said:
They get my vote
Sealed inrunner of just the right size, high quality materials and built to last.
I've been playing with a 3210 for a while - it's the 12t version:
I heard from them today, that the 8120 6t will be back in stock January or February - that's the one I'll use for my next project.
These and the MEGAMax [ http://www.maxcim.com/MEGAMax.html ] should make excellent ebike motors.
erth64net
100 W
Miles said:Tom Tom said:
They get my vote
Sealed inrunner of just the right size, high quality materials and built to last.
I've been playing with a 3210 for a while - it's the 12t version:
I heard from them today, that the 8120 6t will be back in stock January or February - that's the one I'll use for my next project.
These and the MEGAMax [ http://www.maxcim.com/MEGAMax.html ] should make excellent ebike motors.
Where'd you get that pulley? Is it an HTD style? Not aluminum?
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