What motor windings would you go with?

R0ckStar

10 µW
Joined
Apr 19, 2021
Messages
6
Hi guys, I'm new to this forum and thought I'd better join as I am about to become the proud owner of an ebike. I ride escooters and EUC's but the ebike I am really looking forward to as it will most likely be my go to PEV. I will come straight to the point: The ebike I am getting has the following spec:

Motor: 12000w QS273
Battery: 72v 49Ah Panasonic battery
Controller: 150A Sabvoton Controller
Wheel diameter: 21in
Pedal Assist Sensor

I ordered 21in wheels as it will look more like a mountain bike than a dirt bike, I will lose some torque but gain higher speed I believe with a slightly larger wheel? Because I am quite tall (6 ft 3 in) I think this will suit me better and the bike looks better IMO, but that's all relative. I am looking for a motor winding that will give me the best of both worlds in terms of torque and high speed. At the moment the default winding on the motor is 2.5T which I am guessing is super torquey but lacking on high speed and I think a 2.5T can reduce the lifespan of the battery? but I can ask to get the motor customized for a different winding, say 4T or 5T

With the above hardware configuration what motor winding would you guys recommend? I have heard the terms fast and slow windings which I assume would be 2.5T and 6T respectively? I don't need to ride stupidly fast all the time but I like to know I have power there when I want or need it and take the bike off road from time to time but I will be riding on roads mostly. I like a 'torquey' motor so a winding that would get me off the mark very quickly would be great.

Would a 49Ah battery be enough to cater for the above and accommodate what I am looking for?

Your thoughts would be much appreciated and apologies if there has been a similar post to this put up on the forum

Kind Regards

RS
 
R0ckStar said:
At the moment the default winding on the motor is 2.5T which I am guessing is super torquey but lacking on high speed and I think a 2.5T can reduce the lifespan of the battery? but I can ask to get the motor customized for a different winding, say 4T or 5T

2.5T is a high speed winding, 4T or 5T will be slower than that.
 
E-HP said:
R0ckStar said:
At the moment the default winding on the motor is 2.5T which I am guessing is super torquey but lacking on high speed and I think a 2.5T can reduce the lifespan of the battery? but I can ask to get the motor customized for a different winding, say 4T or 5T

2.5T is a high speed winding, 4T or 5T will be slower than that.

Ahhh ok, I had it in reverse, so the 2.5T winding is high speed but lacking on torque?
 
R0ckStar said:
E-HP said:
R0ckStar said:
At the moment the default winding on the motor is 2.5T which I am guessing is super torquey but lacking on high speed and I think a 2.5T can reduce the lifespan of the battery? but I can ask to get the motor customized for a different winding, say 4T or 5T

2.5T is a high speed winding, 4T or 5T will be slower than that.

Ahhh ok, I had it in reverse, so the 2.5T winding is high speed but lacking on torque?


Same motor, same maximum torque regardless of winding. But you'll need much more current (amps) to get it with a low turn count winding.

High turn count means lower RPM and higher torque per amp.
 
Chalo said:
R0ckStar said:
E-HP said:
R0ckStar said:
At the moment the default winding on the motor is 2.5T which I am guessing is super torquey but lacking on high speed and I think a 2.5T can reduce the lifespan of the battery? but I can ask to get the motor customized for a different winding, say 4T or 5T

2.5T is a high speed winding, 4T or 5T will be slower than that.

Ahhh ok, I had it in reverse, so the 2.5T winding is high speed but lacking on torque?


Same motor, same maximum torque regardless of winding. But you'll need much more current (amps) to get it with a low turn count winding.

High turn count means lower RPM and higher torque per amp.

Thanks Chalo
 
So to get a middle ground a 3.5T or a 4T would be the way to go to get an 'all-rounder' machine?
 
R0ckStar said:
So to get a middle ground a 3.5T or a 4T would be the way to go to get an 'all-rounder' machine?

My method is to use the slowest winding that gives me the top speed I want, so I can use a cheaper controller, take it easy on my battery, and get optimum real world efficiency.
 
Chalo said:
R0ckStar said:
So to get a middle ground a 3.5T or a 4T would be the way to go to get an 'all-rounder' machine?

My method is to use the slowest winding that gives me the top speed I want, so I can use a cheaper controller, take it easy on my battery, and get optimum real world efficiency.

That sounds sensible to me for longevity. So in other words I could stick with the default 2.5T winding and enjoy for hopefully many years to come. And I can always upgrade later if I get tired of that setup :)
 
Chalo said:
R0ckStar said:
So to get a middle ground a 3.5T or a 4T would be the way to go to get an 'all-rounder' machine?

My method is to use the slowest winding that gives me the top speed I want, so I can use a cheaper controller, take it easy on my battery, and get optimum real world efficiency.

I use a variation of this. I want a winding that will provide the greatest acceleration up to the top speed that I like to ride. The difference is, that the torque drops off quickly as you approach the motor's top speed, so it takes a longer to get to the top speed. So, a marginally faster winding than what I need to achieve the top speed I want, gets me to my desired top speed faster.
 
Sir you could be eating your handlebars I'd be careful how that throttle and set up. Remember you can always turn it up. The 5t has a lower top speed and will saturate at a lower miles per hour. And not use as much battery.
 
You need to choose the motor that goes the speed you want. From your specs of battery voltage and controller, it sounds like you want a homemade electric motorcycle.

So go with the fast winding, or get a gas motorcycle. If you want more torque, then your choice of wheel size based on looks is dead wrong. If you want more torque, go with a smaller wheel, assuming it is compatible with frame geometry. BTW, a really small wheel will not affect your top speed as much as you might think, but it sure will increase your torque a ton.
 
I am at present running:-

QS273 4T
Sabvoton 96120 (set to supply 110 battery amps)
25ah 22s battery pack. (5p22s Liitokala 26650)
Slightly heavy enduro / stealth type frame
19'' rear wheel (with tyre, close to 26").
I weigh more than I should (125kgs)

The motor winding is fine for me. Acceleration is very good. To much throttle and the front lifts quite easy.
Around town I do between 20 and 30 kph. Out in the country I open it up. 8-kph is easy and it wants to go a lot more, but 80 kph feels good for me.
 
That advice is good, to choose a motor winding that suits your top speed.
But do keep in mind we don't ride on flat ground 0% grade all the time so knowing the terrain you ride is important.
Using the Trip Simulator helps plugging in the google maps route.
And remember its not always wise to speed up a hill as fast as you can, in terms of heat and wh used on the hill you will increase both the faster you go up it but you dont want to go up it at a crawl either :flame:
https://youtu.be/dxJe_gygRGU?t=905


https://youtu.be/dxJe_gygRGU?t=4216

Choosing Motor Winding - https://youtu.be/c96n0Ma2rLY?t=5893
*Exact same motor characteristics, just have to have a scalable controller and battery voltage in proportion to the fast and slow winding. Just a matter of how fast do you want to go for what you happen to have (battery/controller). Choosing geared or dd - fast or reliable = dd, minimalistic, small, lighweight = geared. Heavy vehicle, 2wd,3wd,4wd, party vehicles, cargo hauling.
https://youtu.be/c96n0Ma2rLY?t=8202
He changed the throttle to match @ 2:18:41
Increasing voltage minute later to match motors
Lowers resistance of controller
matches efficiency @ same speed
Base the KV on how fast you want to go.
2:22
Trade off between volts and amps only.
2:23
 
litespeed said:
Post some pictures. Would like to see your bike.

Tom

wallpapaer 20210326_095512 (1).jpg

Bike in it's now state.
At present I am designing a new rear swing arm and also changing the front suspension.
 
Looks pretty good. I like your full fenders.....getting wet/muddy sucks! How big are your tires? Where did you get the fenders? I guess your a shorter guy since your front suspension is set to lower the bike? I’d be using all 8” of that travel. Looks like any decent hit and and your fender will be kissing the controller cover.

Excellent looking ride for sure.

Tom
 
litespeed said:
Looks pretty good. I like your full fenders.....getting wet/muddy sucks! How big are your tires? Where did you get the fenders? I guess your a shorter guy since your front suspension is set to lower the bike? I’d be using all 8” of that travel. Looks like any decent hit and and your fender will be kissing the controller cover.

Excellent looking ride for sure.

Tom

The fenders I chose after a lot of searching are Bluemels 75's. I did like the look of mudhuggers, but wanted a more weather resistant mudguard. Most of my riding is on road / cycle path.
I got them from here https://www.sks-germany.com/en/products/bluemels-75-u/
The front suspension is going through some mods at the moment. Clearance is not an issue as I am now running a 24" wheel, but will be changing the suspension to air.
The bike is set low, but for pedal comfort I have a remote seat dropper. So easy on and off and then adjust for nice pedal position.
 
Thanks for the info. Unfortunately the fenders you have won’t work with the 3.14 inch front & 3.35 inch rear motorcycle tires I’m using.

Thanks again. Looks like mud huggers here I come!

Tom
 
I am buildig that bike right now.

I went with a 40H 273 in 3.5T 19" moto rim, 350A phase, 8kw contin controller. 72v system. 160A contin, . 50 ( 55?) Ah pack of brand new Chevy Volt cells ( 0 miles). IR of the cells together is .0006 Ohm (0.6mOh) ( 1mOh each).

Goal is to break 60mph. Without hurting myself.
 
My rear wheel is 19", the tyre is 3.50 x 19. The overall diameter is 3.50 + 3.50 + 19 = 26"
A 3.00 x 19" tyre would give 25" and a 2.50 x 19" tyre would give 24".
This is based on new tyre, as with wear, obviously the diameter can change (How much would depend on the tread type)
 
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