ALIEN MOTOR RECOMMENDED POWER (W)

[roi011]

Hi

Im about to install electric motor on my 26 inch Haro bike.
Im going to use 148mm DH ISIS BB 444432T chainwheel freewheel crank set -
http://www.cyclone-tw.com/order-chainwheel.htm
with 2 pack of 6 cell lipo (2 X 24 volt parallel).
motor pinion will be 6 tooth.
i want to have your reccomendation about the motor, I thought abour the Alien 6374 90KV 3200W, do you think that this power will be enougth ?
I weight 80kg, max speed calculated 35kmh.

Roi

 

[Miles]

motor pinion will be 6 tooth.

 

[roi011]

main gearing ratio is 44:6, this is why i wrote it.

 

[Miles]

Ok, just wondered if it was a mistake :wink:

I'd humbly suggest that 10t should be the minimum size that you use.....

Ref:
http://chain-guide.com/basics/2-2-1-chordal-action.html
https://www.youtube.com/watch?v=snCRmGY2v9U

 

[roi011]

Ok, just wondered if it was a mistake :wink:

I'd humbly suggest that 10t should be the minimum size that you use.....

Ref:
http://chain-guide.com/basics/2-2-1-chordal-action.html
https://www.youtube.com/watch?v=snCRmGY2v9U

OK, i will consieder it, thanks.
mostley i would like to know if 3200 watt motor is enought??

 

[Miles]

mostley i would like to know if 3200 watt motor is enought??

Only you can decide that : ) No amount of power is enough for some here... On the other hand, max current is 80A which gives you 8Nm for a nanosecond or two. More realistically, 3.5 Nm continuous. 3.5Nm * 44 / 6 = 25Nm torque at the cranks.... Not a huge amount.....

For power and torque requirements, see: https://endless-sphere.com/forums/viewtopic.php?p=312555#p312555

 

[Miles]

PS:

If you want to pedal, you need to reduce the motor speed down to less than 100 rpm at the cranks.

With your present 7.3:1 reduction this will mean the motor running at 733 rpm.

733 rpm and 3.5Nm of torque gives you 270 Watts of continuous power.....

 

[saul]

main gearing ratio is 44:6, this is why i wrote it.

You'll need a much larger reduction for this to work without heating up/blowing your esc, and 6s is a bit low, unless you just want a light pedal assist.

 

[roi011]

mostley i would like to know if 3200 watt motor is enought??

Only you can decide that : ) No amount of power is enough for some here... On the other hand, max current is 80A which gives you 8Nm for a nanosecond or two. More realistically, 3.5 Nm continuous. 3.5Nm * 44 / 6 = 25Nm torque at the cranks.... Not a huge amount.....

For power and torque requirements, see: https://endless-sphere.com/forums/viewtopic.php?p=312555#p312555

hi,
sorrey for my late responed...
please tell me how you calculated 80A??
my setup now is Hobbyking 150 A ESC. motor - Alien 6374 kv, 6 cell lipo-24 volt.

 

[roi011]

PS:

If you want to pedal, you need to reduce the motor speed down to less than 100 rpm at the cranks.

With your present 7.3:1 reduction this will mean the motor running at 733 rpm.

733 rpm and 3.5Nm of torque gives you 270 Watts of continuous power.....

what is the best way to reduce the motor speed? when im usung 50% throttle the motor loose its power and cant pull the load !?
if i will increase the front pinion from 6 to 10 thooth i will have higher speed on the wheel....
i need to find how to "have" the max power from the motor with lower speed (nominal speed of motor is 80kv, i want to reduce the speed by 50% with out loosing power)

 

[roi011]

please look at the project, my problems for now are:
1/ motor runs too fast, calculated speed is 60kmh...(80kv*24volt:ratio of gear=60kmh), i need to know what is the best\easy way to reduce the motor speed.
2/ now, runing the system "on air" only when the motor on its max speed i can "feel" its power, when runing with lower throttle i can stop the motor with my hand... i guess something wrong with my setup\understanding :?

 

[--freeride--]

that setup is nit going to work you need a 60KV Motor and a Second reduction Stage to run through the cranks...
The better way is to go direktly on the rear wheel... and not run through the crank. But then the 60kv motor would be better to. So your Motor is to fast and the reduction to low.


Nice maschined parts by the way

 

[Dunkenb]

I'm thinking of using that motor too,I emailed alien and they recommend a 10s battery for use with it. 8)

 

[roi011]

I'm thinking of using that motor too,I emailed alien and they recommend a 10s battery for use with it. 8)

yes, i thouth of increasing to 10s to have max power, but it will increase the speed and i need the opposite...

 

[markz]

You are not using a freewheel crank?

 

[roi011]

You are not using a freewheel crank?

it is a free wheel cranck.

 

[Thud]

but it will increase the speed and i need the opposite...

You need both (more reduction & motor rpms) if your going to have any success.

my math shows on 6 cells you need to reduce the motors rpm's by 19x. (minimum)

In a single stage reduction with your 6t sprocket - you will need a 114t chain ring. (not realistic I know)
add that 6t sprocket is an engineering joke...total fail waiting to happen, for the reasons in Miles's link.

on 10 cells you need a 31x reduction (again assuming your driving the cranks)

time to study multi stage reduction set ups by many members here.