Who has Experience ?,... Low KV vs High KV?

Who have experience With using Low KV vs High KV motors on their Skateboards?

What are your findings ? , preferences ??

  • Low being 150-190
  • High being 190 and up .
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It all depends on the type of reduction ratio you use. On my first build I used a 290kv Tacon with 14/36 gear ration and have yet to find a hill it can’t climb. So really it’s all up to your preference, unless you go crazy high of course.

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It’s also restricted by your choice of battery. If you’re using 10s then stick to under 200 If you’re using 12s stick to below 190

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most places online in rc groups etc seem to say kv has no relation to torque and it’s all about motor size

so just choose a motor big enough with enough torque, depending on dual/single drive and how heavy you are. Bigger motors tend to have lower kv that limits what you can pick.

Does the battery limit you? if you can just limit the erpm in the bldc tool there shouldn’t be a problem, you could argue that you would be wasting money on extra battery, also isn’t the vesc 6.0 supposed to be increasing the erpm limit?

i’m using 240kv 10S and weigh 180lb, it seems to have enough torque to get up any hill and have reached 24.8mph which i think is the max due to erpm limit

I’m using a SK3 245 KV on 10S, also,… and works fine , just wondering how using a 190KV and Lower Ratio differs in real life use ??

I have used 190kv 260kv and 245kv on 6s 8s and 10s. 6s and 245kv is nice when just starting out east to control smooth and reliable. range is ok. 260kv on 6s is fast but at the same time I enjoyed 245 kv more because of torque. I find 8s with 245kv is the one of the better balanced for a motor like this. 190kv and 10s is nice too but it rewuires a large fear ratio for larger wheels but on 83mms it’s nice

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I also find that running 245kv on 10s at speeds over 25mph burns ur battery life much faster by a few miles even

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Have you tried Lower KV on the same 10S

Yes only li ion too

Did you prefer the lower KV setup?

I honestly preferred 6s 245lv to be honest

I’m thinking of a DR setup using 2x 6355 190kv on 10S with 15T 34T, 85-90mm wheels ?

It’s faster but less controllable I think you will honestly prefer torque over speed so use a large gear ratio 40t

were these motors the same size?

if so then just changing the reduction ratio should give the same performance for both? i wish i could test this as it would show if kv really has anything to do with torque, by adjusting the ratios so that both boards have same top speed and seeing if torque is the same

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it really depends on the motor so far 6s and a tacon has been my favorite compared to 10s and a 6355 r spec, 260kv was the sk3

I have built a few E-vehicles and I am currently working my first electric longboard.

In my experience it is better to have a Low KV motor since less gearing will be required. There is an easy way to calculate the amount of torque the motor will produce. Kv is the RPM constant, Kt is the torque constant. kt = 1355 / kv . Kt is in units of “Oz-In/A”.

Here is an example. If your motor is a 150kv motor. Then it has a Kt of 1355 / 150 = 9 Oz-In/A (approximately).

Now you take your max amp draw, lets say 100A, and multiply that by the Kt.

9 Oz-In/A x 100 A = 900 Oz-In or about 4.68 ft-lbs for torque. This motor output torque is then multiplied by your gear reduction. 3:1 would be 3x the torque, 1/3 of the RPM. Top speed of course is Kv x max voltage.

Side note: For my electric skateboard I decided to use a higher KV motor (720kv) that pulls 128A and runs 12s. This will give me a lot of RPM. I have started to design a reduction system to drop the RPM from 30,000 rpm to around 5,000 rpm. With my gear reduction I should get around 7.5 ft-lbs for torque. The motor is over 5000 watts, and water cooled. Turnigy T20 .

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Idk about this I can say that a better overall built motor In the long run can generate a nicer ride and better control. I also believe that is an incredibly inefficient system tbh

Best experiment would be one using same Battery , same Moror (differnt KV’s)

6364 260KV geared for Torque 14, 40 then 6364 190KV geared for Speed 16, 34 ,… then see the Difference ???

To put it simply kV is a trade off between torque and speed, just like gearing is. Two motors that are identical other than their kV will preform the exact same assuming their each geared for the same top speed. This means a motor with 400kV and a reduction ratio of 4:1 will preform identically to a 200kV motor at a reduction ratio of 2:1.

HOWEVER, the VESC has an RPM limit of 8570. Meaning the motor/battery you choose should not be capable of more than 8570 RPM at top speed. Thus, a 190kV motor at 10S would give you a max RPM of 190kV * 42V = 7980RPM and therefor be okay to use with a VESC. If you were to go with a higher kV motor, say 250kV, the maximum RPM would be 250kv * 42V = 10,500RPM which is too high and you would run the risk of blowing your VESC.

Also, BLDC motor are most efficient around 80% of their top no load RPM, therefore it is best to choose a motor that has the highest kV you can without exceeding the RPM limit. 190kV and 10S are common because they are close to the limit but allow for some headroom.

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What about if you think that most of our riding won’t be done at 42-40V(10S) ,… probably most will be done between (39-36V) ? , should that influence our KV choice ?