Direct-Drive conversion of the new GNG/cycmotor X1-pro 3000w

[Grantmac]

A slightly smaller chainring plus some guides and you'd be in business. Would be such a slick setup.

I'm looking at mounting a QS1000 in the same spot if I can find the right frame (thinking ~07 Norco DH).

 

[crossbreak]

still, there is not enough space. I have a tiny 38T laying around that was originally meant for the rear wheel that I could test fit as chain ring. This combined with a Hammerschmidt crank drive could may work. Maybe i find the time on sunday, shouldnt be hard to test as I can simply turn the sidesheets and insert the motor. The axial position is fixed as is anyway, because of the motors chain line.

 

[Andrewol]

not sure, if it fits your frame/chainline i'd say yes. Also you have to meet your desired reduction ratio though.

What is your reduction ratio? 12T front 36T rear (41mm\123mm effective diameter)? Your max. speed with this setup theoretically +80km\h?
For the highest efficiency you'll have to spin your motor at the max. rpm as well, considering 20S voltage. Taking into account wind resistance, very seldom ride at that speed with tailwind and due to safety concerns, usual ride at average 30-45km\h with this setup won't be efficient enough. Maybe 42T rear could be more common wise?

 

[crossbreak]

the 42t will

a) not fit and

b) will eat up your battery since it will have much higher eddy and hystherisis loss.

You have to spin down to get rid of stator loss. not up. Battery voltage doesnt have noticable effect on this. If you want to go slower to get better wh/km efficiency, then just throttle down or set max amps in your display (if you have a Cycle Analyst or something similar). No need to get a new battery, our bikes all have throttles so you can actually throttle down very efficiently if you want to guess this is your fist ebike? Maybe you should better get a ~350W geared hub to get the the basics and the grin in your face before you decide where you want to go exactly 8)

 

[Andrewol]

So, the main reason it won't fit. I don't wish to discuss, but throttle has not much to do with efficiency of the system, this is just a speed lever for your ride. I think everyone agree. We need highest torque point with lowest phase amps ratio.
As it will be fixed gear, efficiency must be taken into account when choosing reduction ratio at average speed used.

 

[tmho]

So, the main reason it won't fit. I don't wish to discuss, but throttle has not much to do with efficiency of the system, this is just a speed lever for your ride. I think everyone agree. We need highest torque point with lowest phase amps ratio.
As it will be fixed gear, efficiency must be taken into account when choosing reduction ratio at average speed used.

Originally, I also thought that throttle has not much to do with efficiency of the system. But later, I found that crossbreak is right.
The higher/greater the throttle position (higher speed), I will have less km per Ah/wh. The reason for that is the wind drag. You can do a simple test to verify this.

 

[Andrewol]

You are right partially. That's why I wrote before about wind resistance. But with one reduction ratio half of throttle position (fixed phase amps) with given wind resistance and road condition you will have 30kmh. With another reduction ratio and the same other conditions you may have 35kmh. The difference are more or less amps are wasted to heat or converted to drive.
We shouldn't discuss about it, it's obvious. Better to concentrate on proper reduction ratio for a preferred speed with known best efficiency point.

 

[crossbreak]

[...]I don't wish to discuss, but [...]

[...]You are right partially.

:lol: man, i can tell you the same..

we can swap the chain for a #219, then it should be possible to have a 12T to 58T reduction, a total ratio of 29 from wheel to motor. Thats a gain of 1.61 compared to the bicycle chain drive but i guess it will be a lot louder for sure. Not sure if it makes sense in sake of performance and efficiency
for such high rpm setup it is definitely needed to fasten the rotor magnets as they are likely to fly away. I am thinking about wrapping carbon fibre around the rotor :?
i hope i can measure hystherisis and eddy current constants plus the terminal resistance soon so we know more about the feasible rpm range of this small motor. BTW the KV is 167 rpm/V or 0.057 Nm/A according to the manufacturer

Better to concentrate on proper reduction ratio for a preferred speed with known best efficiency point

the 18:1 was shot from the waist. we will be able to calc something as soon as we have those figures. no need for speculations yet

 

[Andrewol]

With 2K rpm on a motor spindle chain isn't an optimal solution here for best performance efficiency value, however most available. If the magnets will fly at that speed, than it's a warranty issue. Is there a space for carbon wrapping?

 

[crossbreak]

yeah, cycmotor will offer a rotor with wrapping soon, the final production rotor will be wrapped/equipped with endcaps as stock part.

2k rpm is almost laughable for a chain. Every car engine goes faster and cam shafts are almost exclusively driven by chains these days. In contrast to toothed belts they last almost forever and eat less power. But lets not discuss belt and chains here anymore, this is and STAYS a chain drive. period.

 

[Andrewol]

Perhaps better would be to redesign the rotor for Cyc with magnets shells like in bbshd. I'm for the chain drive as well now.
Will wait for your test results Crossbreak.
Thanks.

 

[neptronix]

Dang, hate to see your wonderful project still stalled.
I am still on the fence about ordering one of these up.

 

[crossbreak]

one month ago jon from cycmotor told me that my 72V controller will be shipped after 2-4 weeks. Time is over and I dont hear anything anymore. I must admit that i am loosing confidence. At least a 6Fet nucular is finally on its way. Hope it will arrive in 1-2 weeks

if someone asks why i dont try to use a kelly then I want to quote Merlin:

Back to Kelly? never...I'd rather walk

 

[Andrewol]

Do you participate in Cyc owners group in FB?

 

[neptronix]

Yeah, i would not wait for a motor manufacturer to put out a good controller.. I have had so many bad 'paired' controllers with kits in my early days that i learned that lesson long ago..

We've got ASIs.. high voltage VESC variants.. forget whatever the manufacturer is chucking your way, you can probably do better..

 

[crossbreak]

forget whatever the manufacturer is chucking your way, you can probably do better..

better than nucular? That is currently my best bet :?

2k rpm is almost laughable for a chain

Of course rpm of a pulley is not a direct design criterea for a chain or belt. Chain/belt speed is one.this chain drive is within the speed limits of the chain. A belt could do more but wuold not reach disirable speeds within this package while it would exceed desirable force

 

[neptronix]

The nucular controller is pretty badass, although it is still a bit bleeding edge at the moment.

The reason i don't have a huge boner for it is this ( quote from vasilisk )

I told before that im not recommend to run RC motors atm, coz my PWM is optimized for switching loss and these motors have low inductance, that causes high ripple current. It may be better with new update since i've added FOC pid regulators to configuration, you can tune it. Maybe later i will do some work to make it working good with rc motors, but it doesnt seem to be really needed right now.

Yeah.. vesc >v6 does 150,000 eRPM sensorless FOC and can drive ultra low inductance motors. :thumb:
I imagine the nucular controller will work fine for your unit since it has such a low pole count.

ps - i am about to buy an astro motor but i'm holding up to see how your drive works out for you first.

 

[andrebandre]

one month ago jon from cycmotor told me that my 72V controller will be shipped after 2-4 weeks. Time is over and I dont hear anything anymore. I must admit that i am loosing confidence. At least a 6Fet nucular is finally on its way. Hope it will arrive in 1-2 week

Same here.
Only i was quoted 2 months.
I also have a Nuke in the mail but the 12FET version.

 

[crossbreak]

Yeah.. vesc >v6 does 150,000 eRPM sensorless FOC and can drive ultra low inductance motors. :thumb

yeah that is what i thought as well. But i could not find a VESC that runs on 20s

 

[neptronix]

There are some VESCs that can run 18S :thumb:

 

[crossbreak]

yes. just 300 pounds and out of stock http://teamtriforceuk.com/a200s-v2/
18s yes... but only 16s recommended

 

[neptronix]

I missed the fine print, sorry.
Powervelocity is working on a high voltage compatible VESC also.

 

[Andrewol]

Hi Johannes, could you read your PM?

 

[crossbreak]

just read it. I didnt know that something like this is available on ebay, this is more or less my adapter! I ask myself what size this brake disc must be, looks like 250mm or 10" in dia or so

https://www.ebay.com/itm/Motorized-Gas-Bicycle-Bike-39-Teeth-Sprocket-with-Disc-Rotor-Brake-assembly/173938908350?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20190129125700%26meid%3D4ebcca73ffb843cd9e3aa751bc24588c%26pid%3D100752%26rk%3D2%26rkt%3D7%26sd%3D183695664139%26itm%3D173938908350&_trksid=p2047675.c100752.m1982

 

[Andrewol]

I'm going to use 9T front 36T rear sprockets, 4:1 reduction. What do you think about such small 9T sprocket on motor, will the chain survive? Ho it feels with your 12T/36T 3:0 reduction? Ought to be tough for a motor.

Your crankset inside Q factor must be greater than 145mm? Motor width is 141mm. My current cranks are 119mm.

You mentioned that this chain drive is within the speed limits of the chain (410). I can imagine with 9T cog it could be even worse than with your 12T. Perhaps we should consider 219 chain as it's more aplicable for higher rpm or belt drive something like this as an example?
https://www.aliexpress.com/item/Belt-Drive-Kit-For-66cc-80cc-2-Stroke-Engine-Motorized-Bike/32990742821.html?spm=a2g0s.8937460.0.0.4ba32e0eInKKqN
I don't say it's done right, I think it should be 8M pitch at least to handle a torque. Also rear brake won't be available with such a setup.