Motor Review | SK3 6354 245KV -vs- NTM 5060 270KV

onloop

10 kW
Joined
Jun 24, 2013
Messages
600
There seems to be lots of people asking about what motor is suitable for use on an electric skateboard. I selected two of the most commonly used & recommended motors from this forum & did some real world testing.


CHECK OUT THE VID TO SEE WHAT MOTOR PERFORMS THE BEST


[youtube]ioFqJPht2kM[/youtube]

IF ANYONE LIKES DOING STATISTICAL ANALYSIS ON THE RAW DATA HERE IS THE DATA SHEET WITH THE RUN TIMES:
https://docs.google.com/spreadsheets/d/1hnI3sXMS3NYDerEMLpPYJY9Se4gTGP6e4FjirWgXJUY/edit?usp=sharing


Please let the comments roll in
1. I'm interested to know if you have any ideas on how I can improve my testing methods. OR my videos...
2. Other ways you would like to see the motors tested.
3. Tell me about other motors that you want to see compared side by side....
 
cool slides.. :mrgreen: might have to learn to do that..
.
Like everything in life this test could go differently under other circumstances. With different gearings the test might be very different as the sk3s higher torque could probably allow for 8-10% more teeth on the drive sprocket.. Perthaps the original design was based on the NTM making the sk3 under geared. Had the original design perhaps been done on the sk3 (10% more teeth on the drive sprocket) then the NTM might have been under powered uphill, and of equal top speed on the flats.Also the battery consumption of the undergeared sk3 might allow it to go 15-20% further (or is it farther) than the higher amped ntm.

I learned this when i changed from my tacon 245 kv to my current NTMs, and had to go from 19 teeth on my drive sprocket to 16 to maintain acceleration and power to climb as well as max amps, I also noticed i was running out of bateries about 750 or so meters early on my daily 20 km run which the batteries handled well with the Tacon. Once this sprocket change was done they perfomrmed very similarly and satisfactorily.

That said i was rooting for the NTM the whole way, its cheaper looks cooler i-ts much smaller (than the tacon at least) and currently have one going on 1250 kms on my velociraptor board... everybody on the forums says the magnets fall off and have to be reglued.. mine have not, and this little motor has nicks and scrapes all over..and just keeps on ticking.

Congratulations on this video..More tests please. :D
 
Great video mate! Liked and subbed on youtube!

How about a braking distance and startup cogging test? Also, maybe make an ESC and battery enclosures with the same color, that would really complete the look. :wink:
 
Silenthunter said:
Great test!!!

I was thinking about getting more clearance since the numbers are very close.


hey silent hunter, could you explain in more detail? about clearance.... where do you want more of it? are you talking about wheel diameter etc?
 
beto_pty said:
cool slides.. :mrgreen: might have to learn to do that..
.
Like everything in life this test could go differently under other circumstances. With different gearings the test might be very different as the sk3s higher torque could probably allow for 8-10% more teeth on the drive sprocket.. Perthaps the original design was based on the NTM making the sk3 under geared. Had the original design perhaps been done on the sk3 (10% more teeth on the drive sprocket) then the NTM might have been under powered uphill, and of equal top speed on the flats.Also the battery consumption of the undergeared sk3 might allow it to go 15-20% further (or is it farther) than the higher amped ntm.

I learned this when i changed from my tacon 245 kv to my current NTMs, and had to go from 19 teeth on my drive sprocket to 16 to maintain acceleration and power to climb as well as max amps, I also noticed i was running out of bateries about 750 or so meters early on my daily 20 km run which the batteries handled well with the Tacon. Once this sprocket change was done they perfomrmed very similarly and satisfactorily.

That said i was rooting for the NTM the whole way, its cheaper looks cooler i-ts much smaller (than the tacon at least) and currently have one going on 1250 kms on my velociraptor board... everybody on the forums says the magnets fall off and have to be reglued.. mine have not, and this little motor has nicks and scrapes all over..and just keeps on ticking.

Congratulations on this video..More tests please. :D

Yes, the system was designed around the NTM PROPDRIVE. Originally I had the NTM on 12T-36T this had lots of torque, but too much belt slip due to not enough teeth in mesh, at 15T-36T the motor is at its best. Still has torque, braking is better & top speed is verging on scary.

So YES! the next thing I need to do is gear the SK3 245KV motor to its optimal.... I will probably do this buy down sizing the wheel pulley to 34T, this will also allow for testing some smaller wheels too, due to the smaller wheel pulley diameter

However gearing the SK3 like this will likely (I assume) make the it accelerate slower.... Then the NTM probably wins on the 16 meter sprint.

Logically I think the next motor to test is the SK3 6354 260kv...........

Then Single Drive VS Dual Drive.

a battery test would be interesting......
 
Pediglide said:
Great video mate! Liked and subbed on youtube!

How about a braking distance and startup cogging test? Also, maybe make an ESC and battery enclosures with the same color, that would really complete the look. :wink:

So you like the blue colour? so you mean do everything in blue? actually the though had crossed my mind.... the reason i didn't do it yet was actually to keep the board looking a Discrete as possible... the darker colour seems a bit more stealth the components are hidden in the shadows...... however I did just order a batch of aluminium components housing in gun metal grey, it has a bluish shimmer! but still subtle & stealthy.

was thinking about the braking test, thing is with brakes it is ESC dependent so will be different for everyone.

Startup cogging test is difficult one!. I have tuned my setup to eliminate the cogging 95% of the time, and i have it pretty good now through a combination of low power startup settings in the ESC & correct teeth in mesh configuration with rock solid motor mounts that don't flex combined with perfect belt tension they are mostly gone in day to day use (even when powering forward when rolling backwards after doing a 180 slide), however under extreme conditions you can get it to cog...

Actually an example of extreme conditions was discovered during my tests....

You will notice on the video the tests all start from a rolling start.... the reason is It is very difficult to test 100% acceleration from a stationary position. Basically you cant do it reliably.... Ever tested your cars 100% acceleration from a stationary position..... out-of-control.... same thing happens on an eboard.

so that's why i used a two push (about 3 board lengths) rolling start technique.

When trying to hammer it 100% from a stationary position, it results in one of these things occurring.
1. Cogging
2. or the ESC was just cutting out. Maybe it has some high amp cut out feature... need to investigate
3. wheel spin, YES i got wheel spin.... the road was a bit moist for some of the tests..... and because you are planting all your weight on the front wheels!
4. if none of the above happen you fall off.
 
Interesting how, in the 530m sprint, the 6354 has a higher top speed and lower average speed: seems to imply lower acceleration (and thus lower torque) and higher top speed, despite the lower kV + bigger motor. Oddly enough, the SK3 also seems to have more torque when you consider the two hill tests....

The results seem a little subjective/ambiguous to draw any solid conclusions: a more objective/scientific test might be more useful. Stall current, heat characteristics, efficiency, torque, kV, etc...



Personal experience: the NTM's bearings wore really quickly on my board, turning the motor by hand got significantly rougher and efficiency dropped noticeably after a couple weeks of use.

/firstpost
 
brent said:
Interesting how, in the 530m sprint, the 6354 has a higher top speed and lower average speed: seems to imply lower acceleration (and thus lower torque) and higher top speed, despite the lower kV + bigger motor. Oddly enough, the SK3 also seems to have more torque when you consider the two hill tests....

The results seem a little subjective/ambiguous to draw any solid conclusions: a more objective/scientific test might be more useful. Stall current, heat characteristics, efficiency, torque, kV, etc...



Personal experience: the NTM's bearings wore really quickly on my board, turning the motor by hand got significantly rougher and efficiency dropped noticeably after a couple weeks of use.

/firstpost


yeah your right, top speeds might not be accurate... that's why i didn't rate the top speed against each other in the final score... the final score is based on time & cost. not top speed.

Also i am not really testing build quality.. just performance.....

interestingly enough i had an issue with both motors during testing, on one of the NTM motors the 4mm connector snapped at the soldering, actually the wire snapped...
the SK3 after the first few hill runs had copper wire hanging out of it.... so they both have some slight issues.

The top speed data is from an iphone app called map my ride..... Im thinking it is not a perfect method of recording top speed.
I was considering omitting the data due to the fact it didnt add up. But I though people would like to know how fast i was travelling even if it could be over/under reported by 3-4%. I really need a speed radar that the police have.

however average speed reliable.... it is calculated using time over distance.

I think i probably need to use averages of 6 runs for the 530M sprint.... then it would smooth out any errors... Just didn't have time.

And the other issue of running high number of test is battery drain, performance will decrease as the battery is drained more....

So maybe just average of 4 runs over 530m with each motor. Or ideally a fresh battery for each run would be good.

Honestly the SK3 really surprised me. it was really fast! (i thought the top speed would be allot slower but it was very close.)
Using gearing I think i can get top speed of SK3 to be faster than the NTM whilst still having more torque than the NTM that would be nice.... but the SK3 is more expensive too so for anyone on a budget..... i think the NTM is the best buy...
 
Hi Onloop
Perhaps the second gearing test is unnecesary... They WILL beave different as they ARE different...
Example say my 100 lb niece rode the board... the difference in torque might not be noticeable in the hill run, and perhaps not in the short sprint run and probably not in any of the +10 kg runs... all the results would point to a "better" NTK... unless all the gearings were optimized for this test exactly..
If my head mechanic who weighs 350 lbs (conservatively speaking) rode the board the results would be more heavily staggered towards the sk3 perhaps scoring first in all categories, and maybe even stalling the NTK on the harser uphills with 10 kg backpack... unless (you guessed it) all the gearings were optimized for this test exactly..
And none of the tests would prove one better than the other as better would be dependent on the test being made by you, my niece or my mechanic.. Maybe the more interesting test to readers (who are interested in long and reliable lived of their equipment) would perhaps be a Kms till failure test.. (which again woudl be dependent on terrain, dirt, rust, salt content in the air, riding style, maintanance). I know I woudl galdly give up a couple percentages of efficiency to obtain an extra 1000 kms or life on my motor or something like that. Like I said my NTK should be logging in 1300 kms by Monday, and they are running pretty silent and actually (probably thanks to austin's wiimote) faster than they have ever run before.
Also the price difference makes a difference, as they cannot be compared head to head when there is a significant percentual price difference..
 
Hey beto,

you make some good points...

suppose if there was a SK3 270KV -vs- NTM 270KV it would be a better test...

i agree longevity is very important.... & also hard to test...
 
Hey Onloop,


I made my trucks for 6374 motor (too much power - weight) and I regret that now. I went with white captains 80mm wheels (Wheels are 73 mm contact patch. Too wide and touching the belt) which fixed the clearance issue. Now I would choose a thinner motor, smaller in diameter wheels in order to obtain more clearance and get the board as light as possible.
 
Silenthunter said:
Hey Onloop,


I made my trucks for 6374 motor (too much power - weight) and I regret that now. I went with white captains 80mm wheels (Wheels are 73 mm contact patch. Too wide and touching the belt) which fixed the clearance issue. Now I would choose a thinner motor, smaller in diameter wheels in order to obtain more clearance and get the board as light as possible.

wows 73mm contact patch is rather wide.....center set OR offset wheels?.

my mission objective: i am going to keep testing different setups until i find the optimum configuration. that is the one with the: lightest weight, highest top speed, cheapest, most reliable, best acceleration, most torque.

Ill test the 245KV SK3 with a 15T- 32T gearing ratio, its should be nice, and also means lighter / small diameter wheels.

One of the next complete boards i am going to build is single drive SUPER LIGHT WEIGHT....
 
Cool video! Makes me feel good about my order of 2x NTM :D.

I agree with the consensus that there are actually far too many variables in the setup to compare a single element ie the motors with a constant setup. It might be cool to compare the possible design setups, ie what kind of optimal performance is possible to get out of each motor and how much does it cost (at a reasonable reliability). This includes gear ratios, voltages and Ah (I would say based on speed and mass, so design each setup for a certain amount of mass). This would give you a better idea of performance as you could do reliable time-distance tests, maybe around a circular track.

In this kind of a study there would also be two other things that would also be important in the case of these two motors: the different voltage capabilities (NTM is max 8s and SK3 is max 10s), which will have a significant effect on top speed and also the efficiency (time it takes to run down batteries), n=(W_mech)/(W_elec).

It could also be cool to test the motors in star termination.
 
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