Light, high torque, powerful mid drive motor choices

speedmd

speedmd

10 MW
Joined
Nov 14, 2012
Messages
3,339
Location
new england
Looking to build another mid drive. Single reduction (motor direct to left side of rear wheel) to eliminate all mechanical complexity issues other than the drive chain and sprockets. Motor size targets are 6 -9 inches in diameter, 10 -14 pounds, and motor body length of 4 -4.5 inches max. I can go wider if need be, but do like the size of the original GNG block, but looking for much more power / torque / speed / RPM. Plan on running 18 - 20s lipo at under 100 amps on a modded downhill or XC frame.

Motor and controller budget is somewhat limited, but will spend a few K on the project if performance is warranted. First question I have is anyone in the group successfully using a Joby, Plettenberg Nova or similar size/power motor on a ebike application. Please share results / controller stories (with hall sensor/sensorless) if so. I do like the look of the zero motorcycle motor, but a bit large / pricey for the build. Also like what LFP suggests, which is to use a larger motor without the need for gearbox /gear changes. Plan is to gear it for great -super acceleration / steep climbs at the expense of ultimate top speed unless I can get it to rev forever. Any input is welcome.
 
With a quick evaluation of your idea & goal package....I can only see the Joby JS1 fitting the parameters.
& you can get it wound any way you want it...including split into a 6 phase/2 controller scenario.

IIRC, toolman2 had one....but I don't think he's shown us a build with it yet.
I will be watching.....& curious to see the results.
 
I am currently just sorting out the wider 1000watt rickshaw or GNG type motor for left side direct drive, I have been running the 500w version direct drive to the rear freehub for over a year with 5000 watt peaks and no issues using kart 219 sprockets with a Lyen 12 Fet.
So far I have 2 of the 1000watt motors which I have upgraded the bearings to SKF turned the motor shaft down to accept a 219 sprocket with a key way machined in and upgraded the phase wires to 10awg plus fitted a temp sensor but I am probably 2-3 weeks away from mounting this to a bike.

I also have 2 more on the way from China.

As soon as I have more results I will post them here.
 
Hi Speedmd,

Not sure if you know about the BHT "Big Block" motor.. here's the relevant thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=57483

The name of the thread is slightly confusing as it has "GNG" in the title, but it relates to the BHT motor.. it is a big block motor that is "an alternative to the GNG big block" is how I read it.

It has a lower kV than the GNG big block motors so requires less gearing reduction (5:1 +/- is common).

I am not sure if you would call it light or small, but it meets your other criteria of suitability for single reduction to the back wheel and reasonable price.

Several members have bikes running with these motors and all seem happy with the performance, and none that I know of have blown them up or had other problems.
Dave
 
For gearing I have been using a 5.8 reduction. 13 front and 76 rear. But on the 1000w motor I am going to start with a 16 on the motor and work out what suits best for my needs. I have not tested top speed for a while but I have had 48mph with a different ratio on the smaller motor. All my riding is off-road so top speed not as big a requirement as torque for me.
The smaller motor is currently on a bike with a clyte HS 3540 set for 4500 watt so 9500 watts total
What I can tell you is the smaller motor pulls much harder than the 3540 for the same power input
 
Thanks justforfun. The GNG 450 motor does pull strong. I have one running in the stock (through the crank) config with a 30 amp controller fed with 18s lipo. In lower gears, it feels near to braking something for certain. I want something the feel of that bikes lightness and acceleration in lower gears, with 3 - 4 times the power of what I am running now. It will be mainly off road also.
 
[strike]What is the weight of the Joby motor? Seems they listed all specs but the weight on their website.[/strike]

It was all there under mass :oops: :oops: :oops:
 
They are incredibly light for the rated power. On miles motor summary chart they are off the scales with respect to specific power/ torque. I am hoping some of the veteran builders will share some of their experience trying to get them going well in the app. Some have suggested they may not be suitable to run outside of the designed RPM range(built specifically to spin a prop). Not crazy about the back half only support on them either but may give one a try if it can be controlled well. Size / weight wise they are the bench mark for certain.
 
Due to the light weight and hi power output one those Joby motors if they don't perform good under say 5,000 RPM you might wanna consider a light weight racing variator/clutch setup. I know - everybody will come out and say it is stupid due to loosing power in the clutch, added complexity and added weight. But for these motors I think it really could work out great. Because they have such high performance and light weight you could easily tolerate a few more lbs of weight to use the motor in best performing power band all of the time.

You will have endless setups you can use. Light weights in variator, or heavyer weights. You can play with secondary clutch by changing spring stiffness. You can easily change spring and or weights for any specific trail, riding style or needs. As easy as swapping a spring - done in 15 minutes. Or you could just find the setup that works best for your most common use and just stay with that.

You can gear them so that you let motor spin up to desired RPM before engaging. And that will let motor work in it most optimal powerband all the time. Great acceleration, climbing the steepest hills and yet have awesome top speed.

Back in the days we used to play around with those variators and clutches for our snowmobiles. Power was sort of limited, and in order to get maximum fun factor in terms of acceleration, hi-marking in steep mountains and yet have decent top speed we put much afford into the cluthces. And the reward was awesome.
 
Agree, a centrifugal go cart /mini bike clutch or a snowmobile v belt clutch would work. The v belt setup would allow for multi ratios also. Nether would allow regen / electro braking. This is a long term /learning project and want to dig into it a bit more to learn the controller side much better than I understand now. For now, I think the fewer parts needed, the better. Will see where this leads me in the coming months.
 
AFAIK Sora Lito uses v belt clutch - but I have no idea of the weight of that clutch. But for sure you can dial it in to fit your every need.Not to say any e-bike should be as fat as the Lito it could sure use a diet :)

If only my pockets where deeper.........

383777019.jpg
 
Thud said:
With a quick evaluation of your idea & goal package....I can only see the Joby JS1 fitting the parameters.
& you can get it wound any way you want it...including split into a 6 phase/2 controller scenario.

IIRC, toolman2 had one....but I don't think he's shown us a build with it yet.
I will be watching.....& curious to see the results.
Click to expand...

Yes, the joby is awesome, they dropped lamination size to .12mm and are happy to do 9000rpm, inductance is very low.

Heres the latest race from a couple of weeks back where the JOBY was pushed pretty hard, it turned out to be more like a wet speedway track
with 450's topped out in 5th at around 140 k's -way higher speeds than we're used to and we dropped from 121 rear sprocket teeth to 109,
100 and then 80, ending up at 380 phase amps to the motor to not lose any acceleration.
with no active cooling the windings got to about 100 deg c. These motors have incredible torque density and efficiency.

enjoy, https://www.youtube.com/watch?v=cxBbNV6jK8E
 
ThatS awesome.
the e-bike looks a little (shall we say) "frail" at those speeds. :twisted:
interesting track also....nice to see something that isn't littered with jumps every 20'.

is that a Kelly controller with the erpm's jacked up?
or have you gone a bit more sophisticated?

thanks for the share & thread bump.
 
Joby Dirtbike: How much, and where can I get one?
 
toolman2 said:
Yes, the joby is awesome, they dropped lamination size to .12mm and are happy to do 9000rpm, inductance is very low.

Heres the latest race from a couple of weeks back where the JOBY was pushed pretty hard, it turned out to be more like a wet speedway track
with 450's topped out in 5th at around 140 k's -way higher speeds than we're used to and we dropped from 121 rear sprocket teeth to 109,
100 and then 80, ending up at 380 phase amps to the motor to not lose any acceleration.
with no active cooling the windings got to about 100 deg c. These motors have incredible torque density and efficiency.

enjoy, https://www.youtube.com/watch?v=cxBbNV6jK8E
Click to expand...


Amazing vid. Can you share more? What controller(s)? Pics or vids to share?
 
speedmd said:
Looking to build another mid drive. Single reduction (motor direct to left side of rear wheel) to eliminate all mechanical complexity issues other than the drive chain and sprockets. Motor size targets are 6 -9 inches in diameter, 10 -14 pounds, and motor body length of 4 -4.5 inches max. I can go wider if need be, but do like the size of the original GNG block, but looking for much more power / torque / speed / RPM. Plan on running 18 - 20s lipo at under 100 amps on a modded downhill or XC frame.

Motor and controller budget is somewhat limited, but will spend a few K on the project if performance is warranted. First question I have is anyone in the group successfully using a Joby, Plettenberg Nova or similar size/power motor on a ebike application. Please share results / controller stories (with hall sensor/sensorless) if so. I do like the look of the zero motorcycle motor, but a bit large / pricey for the build. Also like what LFP suggests, which is to use a larger motor without the need for gearbox /gear changes. Plan is to gear it for great -super acceleration / steep climbs at the expense of ultimate top speed unless I can get it to rev forever. Any input is welcome.
Click to expand...

subbed, as this is almost exactly what im looking for too. the rv160s looks ok, but i'd rather spend an extra few bob and get something really nuts, though probably not as much as a joby - dont quite have the doh for that sadly. Anyone know what the NT power motors are worth? http://nt-power.eu/engine.html. I assume jobby prices or more...

lol should have looked at the dates. but yea... any word on this, or toolman2, any details on the joby bike?
 
> Anyone know what the NT power motors are worth?
> http://nt-power.eu/engine.html. I assume jobby prices or more...

The price I have seen ~2 years back was around 1.500 Euro - I don't remember the source.
I am not 100% sure they are still producing the motors (rumors, after Flytec stopped their production )
But I have seen one of the NT-power motors last September, installed on a new motorized paraglider at an exhibition in France.
So the PG-Backpack-Motors were displayed for sale which gives me hope that they should still be available.
The motor looked nicely made, just like in the pictures.
I am interested in that motor as well, so if you contact them and can find out more, please post the information here!

Thanks,
Ulli
 
Snowchyld said:
lol should have looked at the dates. but yea... any word on this, or toolman2, any details on the joby bike?
Click to expand...


Hehe don't think you will get a response on that one any day soon. Some secrecy going on on toolman2's joby bike I think. Guess he is still dialing in the details, hopefully he will share with us when completed. I've been checking forum daily for a few months hoping to see more details.

Toolman2, do you hear us? Details pls.
 
Some interesting looking outrunners.

20 KW. 24cm dia. choice of KV
http://mymobilemms.com/OFFTHEGRIDWATER.CA/Brushless-Motor/20kw-238-50-Lightweight-Large-Brushless-Motor
238-50b.jpg


40kw 20cm dia, 80mm wide 6.4Kg
http://mymobilemms.com/OFFTHEGRIDWATER.CA/Brushless-Motor/40KW-BLDC-Brushless-Motor-100hp
https://www.alibaba.com/product-detail/202-80-powerful-bldc-motors-with_60727607300.html?spm=a2700.galleryofferlist.0.0.880d6245rS3MXL
BLDC-MOTOR-a2.jpg



15kw 21cm dia 80 wide 5.2Kg
http://www.rotexelectric.eu/products/bldc-motors/rex-series/
rex_30-1030x730.jpg

rex_30_03.jpg


15kw 20cm dia 57mm wide 5.2KG
http://www.nt-power.eu/motor_m.html
21_82.gif


15Kw 16cm
https://frchobby.en.alibaba.com/product/60802391219-811433165/MP_15470_30kw_60kg_thrust_Sensorless_Motor_for_Drone.html?spm=a2700.icbuShop.41413.35.2df04df72DV8qj
 
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