HXT 63-74 200kv Brushless Outrunner on an E-bike

[steelefist]

I've built a 1000 Watt scooter (750W over-volted) that gives half decent performance.
http://www.evalbum.com/1696
But i want MORE power! I want the fun of the build again, not just the end of the journey!
So I have a new plan. I'm thinking about building an electric mountain bike, but one which will look very discrete and barely noticeable to be electric from a distance. Yet one that packs an awesome punch.
People have mentioned this 6000W HXT monster RC motor that could be a potential EV motor. 6kW though seems like far too much power. A mountain bike chain alone would struggle to cope with 8 hp. So I've found a smaller version for a lot less money.....
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=3890&Product_Name=HXT_63-74_200kv_Brushless_Outrunner_(Eq:5240)
With a 2.8kW MAX input from my NiMh battery pack from my previous build I reckon this motor would be a very decent candidate! Over 3hp on a mountain bike should provide great performance on the flat, but what about off-road??

These RC motors are great at handling high current loads. I will arrange my NiMh packs into a 24V x 2 parallel system capable of >100A peak, but I am very very dubious about the torque of these motors. they are used to spin props on rc planes with no load apart from air resistance on the blades. Not for driving high loaded wheels. Could it actually move a bike if geared to a standard "normal" ratio we would use for a normal brushed motor, e.g. MY1020 and MY1016 models.

There's a very simple 100A speed controller on the same website....
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7341&Product_Name=SuperSimple_100A_ESC
coupled with a £10 servo controller from ebay the entire package of motor+ESC+"throttle" INCLUDING P+P FROM USA TO THE UK is only £70!!

about $140!!! Absolute bargain, too good to be true??

So does anybody have info on the torque these motors can produce for an application such as an e-bike or e-scooter?

 

[MitchJi]

Hi,

http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=4625

http://endless-sphere.com/forums/viewtopic.php?f=3&t=5156
http://endless-sphere.com/forums/viewtopic.php?f=6&t=5168

http://www.wisil.recumbents.com/wisil/shumaker/default.htm
http://endless-sphere.com/forums/viewtopic.php?f=6&t=3904#p57685

http://www.endless-sphere.com/forums/viewtopic.php?f=10&t=5394&start=0&st=0&sk=t&sd=a

 

[steelefist]

cheers mitch!

 

[Dee Jay]

I am very very dubious about the torque of these motors. they are used to spin props on rc planes with no load apart from air resistance on the blades. Not for driving high loaded wheels.

I've been thinking about using an RC motor also (blue) . Don't know if it's been mentioned or been done... my concern is (side load?). I think the answer would be to beef up the motor bearings (black), fit an additional bearing at the tip of the shaft (green), reinforced by a block of aluminum (red) as part of the motor mount (pink).

Savvy?
:wink:

 

[MitchJi]

\
There's a very simple 100A speed controller on the same website....
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7341&Product_Name=SuperSimple_100A_ESC
coupled with a £10 servo controller from ebay the entire package of motor+ESC+"throttle" INCLUDING P+P FROM USA TO THE UK is only £70!!

Hi,

I think you should choose the controller very carefully.

 

[steelefist]

I have the 100A ELF ESC, It has a red and a black wire one side (presumably for the battery system) and 3 wires the other side (all are black). The motor has three wires red, green and black. Before i blow anything does anybody know how to connect the ESC to the motor? I don't want to get these wires mixed up!

 

[Miles]

As long as you get the connections between the battery and the ESC the right way round, you'll be fine. Connect the wires between the ESC and the motor in any combination and swap two of them if it runs in the wrong direction.

 

[swbluto]

Need UPDATES!

 

[Jason]

Hey, I did a similar set up to what you're thinking about. And as the previous post said be careful about the speed controller. I'm using a turnigy sentilon 100A hv esc... Well not reallly using it still trying to figure out what's wrong with it. So far I've found a bad solder joint and a missing diode. Anyhow I'll include pics of the motor mount, it's very crude done with jigsaw and some brazing but it seems to work out fine.

 

[steelefist]

Just updating on progress, I've stripped out the 1000W My1020 motor and the 48V speed controller from my frame....
http://www.evalbum.com/preview.php?vid=1696

I've finally got everything I need to start the conversion. It was a nightmare getting a 25# sprocket with a 10mm bore diameter with fewer than 12 teeth. I couldn't find a single supplier in the UK so it had to come from USA. So I'm tretaing this component like gold!

This is the difference in size compared to the previous lower powered motor!
IMG]http://i97.photobucket.com/albums/l224/steelefist/DSC00844.jpg[/IMG]

Frame with disc brakes has lost all the weight of the motor and motor guard system which weighed around 4kg, plus whatever the motor was.

Instead of the previous 13:52 gear reduction I am now using a 11:80 on a 25# chain to bring down the 4000+ RPM to a useable figure. The greater ratio will lower the top speed but I want acceleration now. Brutal acceleration.

Motor really is a masterpiece. looks stunning and such high quality.

Connected to hard wood this will easily fit onto the back of the scooter, but at a much lower weight cost than the previous steel frame components.

Just rebuilding the battery pack now with PVC. My NiMh cells will form a parrallel pack providing 24 Volts and 28Ah.

just a question..... Somebody mentioned that with these motors they do not run on DC. So, a 20amp max rated battery can provide effectivel 40A. Something like this anyway? Is this true.

 

[swbluto]

I've heard they're brushless motors with a 3-phase AC waveform that's generated by the correspondingly needed brushless controller that itself is powered by DC power(usually from a battery). The motor can consume more current than the battery puts out if D, or the duty cycle of the controller, is less than 100%(Either when throttle<100% or the battery current is being limited).Using the latest version of my e-vehicle calculator, http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=6892&start=75, you can see what the motor current and battery current will be at different speeds. The part you can see is the graphing feature I've tacked on.

Did the motor automatically come with that frame-box?

 

[recumpence]

I am very very dubious about the torque of these motors. they are used to spin props on rc planes with no load apart from air resistance on the blades. Not for driving high loaded wheels.

I've been thinking about using an RC motor also (blue) . Don't know if it's been mentioned or been done... my concern is (side load?). I think the answer would be to beef up the motor bearings (black), fit an additional bearing at the tip of the shaft (green), reinforced by a block of aluminum (red) as part of the motor mount (pink).

Savvy?
:wink:

I use an outer support bearing on my setup. I did so, not to prtect teh bearings, but to eliminate the shaft flex from betl tension.

It is not really needed in most situations.

Matt

 

[steelefist]

Cheers. The frame for the motor was a cheap extra from hobbycity, but massively helpful for mounting the motor. Was just under Brushless motors > Motor Parts on the website.

I've fitted the motor onto hard wood (because I don't have the tools for metal working!) and fitted this onto the rear of the scooter.

 

[etard]

Updates please!!! Did you ever get this motor going? I am interested in the quality of the HXT

 

[swbluto]

Hey, it seems that i picked the exact same motor as you did! I have some questions...

Did yours mention "Turnigy Aerospace xp C63774-200" on the product label? Mine mysteriously did and it doesn't seem like anyone makes a similar reference to it, but it appears to be the right product and a "Turnigy 200Kv motor" doesn't appear to exist. Also, how long is the shaft that exits from the motor? And where/how did you come up with that 11t motor sprocket? I can't seem to find a sprocket/timing-pulley for the 10mm-wide shaft, but they must be out there somewhere! I'm willing to increase the inner diameter of a smaller one to make it fit, but I don't know which ones that'd be safe on.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=7409&start=15 - Here's where I detailed my find. I measured the windage resistance of my motor to be about ~.03 ohms, which would seem to make for some serious speeds possible using my simulation program for prediction.

 

[steelefist]

I'm at work at the moment so not completely accurate but I'd guess the shaft extends about 1 inch out!
I didn't come across that label on the motor. Seems strange that it would have it on but perhaps there is an alternative technical name used for the motor. One not known to customers.
I know, they are an absolute nightmare to get hold of!! I got my special sprocket from monsterscooterparts. They are the only company in the world I could find that supply the exact sprocket I needed!! Some places do them to match the 10mm bore but with more teeth than i wanted! I'm gearing this thing for acceleration rather then top speed so I'm using 11 tooth : 80 tooth.

I'm at the same stage at the moment. In order to fit the chain I have had to move the rear axle assembly about 20mm in, which has brought the rear tyre right into the wooden motor base! So I'm remocing a small section of the motor base to accommodate the spinning wheel!
I've never used RC speed controllers before so very anxious about powering up this motor for the first time. Might put in a 5 or 10 A fuse just to be ultra safe the first time it goes live!!

 

[recumpence]

I would not use an inline fuse. If the FETs see a voltage dropoff, they can blow.

What controller are you using and what style PWM driver for it?

Matt

 

[steelefist]

The controller is just a cheap style 100A ELF off ebay. My battery pack should be putting out around 90 amps so i thought this one would do, as I'm trying to keep the costs down. I would have preffered using 48V and lower amps but this motor will already be exceeding 4000rpm at 24V!

 

[recumpence]

The only concern I have is the controller. You can skimp on motors and batteries, but the controller is critical.

I am interested to see how your controller runs. If it works well, that would be a good thing. The only controllers we have found to be truely stable and not ultra expensive are Castle Creations. It would be good to find another useable controller. So, I am watching with a curious eye.

Matt

 

[swbluto]

Thanks for the source! I was also looking for a ~10mm ID sprocket with 11-teeth and you found it! I'm not as fanatical about acceleration, but I want as "fast" as hill-climbing as possible and those usually go hand-in-hand for more modest current limits.

Now, I'm curious, how did you secure the motor sprocket to the motor's shaft? I noticed the motor's shaft didn't have a bore hole and the roundness of it doesn't seem to lend itself well to being "ultra-secured" like, say, a D shaft or a double-D shaft, and I was told by an ACE hardware employee there's a "torque limit" with trying to secure it using the "set key" on a round shaft without a bore hole. Do you think this motor is well within that "torque limit"?

I have no experience with set keys and the such(Well, beyond my puny erector set about 8 years ago!), but I can imagine it slipping under high enough force.

 

[steelefist]

Yeh that is a very good point, one which I was thinking about. I was going to try and do a D shaft modification - by basically grinding down part of the shaft and fitting a D bore sprocket. But I didn't want to do irreversible modifications to the motor. So, as it stands at the moment, the sprocket is secured on using a grub screw. I had to make the grub screw myself as motorscooterparts didn't supply one to fit - (which i reckon is absurd) - from a sawn off screw. This has been tightened on as mush as i can do without stripping the threads, so I'm hoping this will hold.

The 11 tooth sprocket is a relatively small sized master sprocket which should reduce the resisting force on the motor. (i.e. a 20 tooth sprocket will be harder for the motor to turn, putting more force on this one and only grub screw). Only time will tell!
I'll test the controller this week and see if the system is working! I'm gonna use a 12V lead acid first in case this dubious ELF 100A controller wants to do a bit of shorting. then at least my NiMh batts will still be safe!
I'll get a video on youtube and link it to show you the motor spinning. If it spins at all!

 

[swbluto]

Ok, I see. I'm as reluctant as you are about modifying the motor's shaft so I'll be testing the grub screw too. With the way it seems to dig in, I'm thinking it'll work for the 200-300 lbs of force the screw should experience at max(The motor puts out 5 NM at start-up assuming the battery current is limited, which comes out to 1000 newtons at 5mm radius, or ~100 kg at earth's gravitational field or about 220 lbs. It only decreases from there.) and probably much less considering it's not "stalled"/"completely resisted" per se.

I'm now getting everything assembled for testing on the original belt-drive system of my scooter but now the issue is the connectors. What kind of connectors are these? I'm thinking about lopping them off and replacing them with 45-amp power-poles just to make life easier, but seeing one motor manufacturer's warning to never shorten the motor's wires has me a little worried(Although I don't understand what the big deal is if it's done properly.) and I wonder if the "45 amp" connectors can safely sustain 70+ amp current without melting.

 

[steelefist]

The connectors on the motors are a bit strange on mine, I've never come across them before. I think I may change mine too once I have the system working properley. (Just gonna do a simple twisty wire connection at first). What controller are you using for your motor? I've been looking at the controllers on the hobbyking website where the motor is from, and it seems my ELF 100A ebay controller is very very similar to the super simple 100A controller from that website.

(http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7341&Product_Name=SuperSimple_100A_ESC)

One review has mentioned that controller handles outrunners poorly and is more suitable for inrunners.

So been lookin at another....

(http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=4316&Product_Name=hexTronik_PRO_120A_BESC_w/_PC_Programmability)


Because of my concerns over this cheap controller I might just completely change it before using it for a more expensive, better suited model! Things are so much easier with a brushed motor!! lol

 

[swbluto]

I'm actually going to test out my Crystalyte pedal-first controller. It's kind of questionable if it'll work, but if it does, that means less investment(and potentially less wasted money that experiments seem to be inclined to do!).

Doing some calculations, it appears the Back-EMF has to be like 5-6 volts for the controller to even start operating, so it appears the motor will have to be going 1000-1200 RPM which with my gearing and all appears to be around 6-7 mph before the controller kicks in. I hope it isn't too hard!

 

[steelefist]

Hey sorry for no updates in months, been very busy at work so no major updates to make.

I'm selling my 40 F 14000mah Nimh cells on ebay and buying four 5000mah 18.5v li-poly packs from hobbycity. Wiring these all in parallel will give me 18.5V, 20Ah, 4000rpm at the motor with constant current capability of 150Amps (not necessary on the particular build). If I get really crazy i'll wire them 2 series 2 parallel giving me over 7000rpm at the motor.

I'm making a few changes to the way the motor is secured.

I'm getting rid of the 100A Ebay ELF ESC and buying a more substantial 120A ESC from hobbycity with good reviews. I just don't trust the ELF 100A ESC after hearing about one setting on fire almost.

The reduced battery weight (about 7-8kgs!!) as well as a huge area in the scooter body may allow me to actually carry the charger on the scooter. Probably won't though and will just use the weight loss as an acceleration advantage.