Motor Math adds up to be the same.

[Jerold]

I'm at a bit of a loss about the Kv/Voltage and amps(or Watts consumed). All the end numbers are pretty constant so why does it matter?

Using this T&P Motor, because it conveniently has the specs for KV/Voltage options and the corresponding Max Amps assuming input not output. For instance I can run an 800Kv motor on 12s (50.4V) and get 40,320 RPM. Or I can run a 600Kv motor on 16s(67.2V) and get 40,320 RPM. The input Watts are just over 15K for both. So what's the deal?

When I calculate [RPM = Kv*S*4.2V] the max RPM, for all versions, it runs about 37-40K.

I looked at the input power for a reference. When I calculate [Input Power(W) = Volts*Amps] the max input, for all versions, current it's about 14-1500 Watts.

In all cases the numbers are essentially constant. So why would I want a lower or higher Kv? Does the lower Kv give me more torque and quick acceleration, where the higher Kv would give me more top end power? But I could also use gearing to adjust the torque or top end back to why?

 

[Chubaka]

The link below will explain kv. Basically lower kv or turns is more torque and higher turns and kv is more rpm per volt for speed.

Also the heat factor. For heavier cars or 4x4, the lower kv may run cooler then higher.

https://www.rctalk.com/forum/threads/turns-winds-kv-and-poles-explained.132791/

 

[WickedFog]

The link below will explain kv. Basically lower kv or turns is more torque and higher turns and kv is more rpm per volt for speed.

Also the heat factor. For heavier cars or 4x4, the lower kv may run cooler then higher.

https://www.rctalk.com/forum/threads/turns-winds-kv-and-poles-explained.132791/

Actually, higher turns is more torque and vice versa

 

[tntpoof]

lower kv is more torque .

 

[Chubaka]

Actually, higher turns is more torque and vice versa

My bad. 4 am and just woke up.

 

[WickedFog]

lower kv is more torque .

Yes. Chewy was correct about the kv.

 

[tntpoof]

anything opposite of what Fog said is correct .

 

[WickedFog]

anything opposite of what Fog said is correct .

You're either unable to read, or are just not a very smart man.

 

[STONER RC]

You're either unable to read, or are just not a very smart man.

No his just ignorant as*hat

 

[WickedFog]

 

[STONER RC]

I'm at a bit of a loss about the Kv/Voltage and amps(or Watts consumed). All the end numbers are pretty constant so why does it matter?

Using this T&P Motor, because it conveniently has the specs for KV/Voltage options and the corresponding Max Amps assuming input not output. For instance I can run an 800Kv motor on 12s (50.4V) and get 40,320 RPM. Or I can run a 600Kv motor on 16s(67.2V) and get 40,320 RPM. The input Watts are just over 15K for both. So what's the deal?

When I calculate [RPM = Kv*S*4.2V] the max RPM, for all versions, it runs about 37-40K.

I looked at the input power for a reference. When I calculate [Input Power(W) = Volts*Amps] the max input, for all versions, current it's about 14-1500 Watts.

In all cases the numbers are essentially constant. So why would I want a lower or higher Kv? Does the lower Kv give me more torque and quick acceleration, where the higher Kv would give me more top end power? But I could also use gearing to adjust the torque or top end back to why?

Yeah the math basically will work out to be close or the same. But when you take a 4x4 1/8 - 1/5 heavier RC trucks.. You want lower KV. To help combat the heating of you esc and motor. With a higher KV that motor would be burnt out in one or less.. there's alot more involved then how you are looking at it....

 

[nino]

I'm pretty sure there must be some video by John of Holmes Hobbies where it's explained... Either way, rule of thumb seems to be smaller vehicles & smaller motors - higher KV, and vice versa.

 

[Jerold]

Yeah the math basically will work out to be close or the same. But when you take a 4x4 1/8 - 1/5 heavier RC trucks.. You want lower KV. To help combat the heating of you esc and motor. With a higher KV that motor would be burnt out in one or less.. there's alot more involved then how you are looking at it....

So theoretically I can run what ever motor fits and just batteries in batteries and gears until I get what I want, but eventually the heat will get me on the lower (higher Kv) torque motors. Torque is good but requires more volts.

 

[WickedFog]

So theoretically I can run what ever motor fits and just batteries in batteries and gears until I get what I want, but eventually the heat will get me on the lower (higher Kv) torque motors. Torque is good but requires more volts.

With all RC's, there is a kv/turn range that will work best with available pinion/spur combos for that vehicle. You might as well throw tire size in there as well, because it affects the total ratio of the drivetrain. 4wd vehicles do better with lower kv/higher turn motors just because of the added rotational mass and friction of the additional drives.

 

[HPIguy]

Please keep it civil folks, or vacations will be handed out as needed.

 

[STONER RC]

So theoretically I can run what ever motor fits and just batteries in batteries and gears until I get what I want, but eventually the heat will get me on the lower (higher Kv) torque motors. Torque is good but requires more volts.

Ok bud here we go the volts have nothing to do with it... the lower kv is more tourqe the higher kv is more rpm = speed and also heat when installed into a big heavy rc truck. Therefore you want a lower kv in bigger heavier RC 4x4 trucks. And higher kv in little baby buggies and short course trucks. Which are lighter by far..

 

[killster]

more Torque = higher speed quickly but not top speed, like low gears and high gears