At this moment I had, 10s 190kv with 107mm. Hit around 50km/h top speed. I want something close to that on my trampa. I weight only 60kg and my trampa will have a 12s battery pack
If you want about 50km/h top speed with 1:4 I would choose 130kv for 7" or 150kv for 8".
Just as a side note, APS motors are quite loud in FOC so your ride won’t be “silent” with helicals, only during coasting. Since I changed to helicals on my MTB nobody turns around, even the dogs don’t hear me coming and only start barking when I already passed by 
The board sounds like a bicycle or e-bike with SK8 motors.
My commuter with belt drive and dual APS 6355 motors is much louder and people turn around and dogs hate me earlier or block my way.
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Thnx for your answer. I was thinking about those APS motors because of the longer stator. But those motors are noisy?
I want something silent. I was running now a belt drive with a APS motor and the noise in foc was good for me.
I don’t want to confuse you, the noise then might be alright for you. Just wanted to mention because you wrote “helicals” that APS motors seems to be louder than others. So far I had motors of 4 different brands running in FOC and APS are the loudest.
I only have the 6355 but I’ve heard from other people as well that APS are loud in FOC compared to other motors. For example SK8 (and I think SK3) are not noisy in FOC.
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I understand. I want to enjoy the silence of the helical drive. It is difficult to understand the thing loud. It is for each person different 
I heard some bad things from sk8 motors. Like strange noises etc after 150km.
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Thanks for correction. You are right. And 65% * 135% is close enough to 100%
This is closer to reality than what we commonly see, where all 63xx class motors are described as “80A” motors regardless of Kv
Motor wattage ratings are not to be trusted, because our applications its current that kills motors, not wattage. Furthermore, high Kv motors have fewer windings, so they can use shorter, thicker motor wire, which means less winding resistance, as less heat. This is why high Kv motors handle more current, and can handle more electrical power.
The 4400 W / 3500 W “ratings” reflect this somewhat. In my estimation though, Kv is proportional to motor max current for the same size motor. the 190 Kv motor should be close to 30% more powerful than the 150 Kv motor, assuming you have the electrical system to supply the extra power.
Thus you ALWAYS want to go higher in Kv when possible, then adjust gearing to bring the speed back down. Obviously dont go so high in Kv to go over the 60k erpm limit, and dont go so high in Kv that it would take wheel pulleys larger than your wheels themselves to achieve the gearing you want, but otherwise, when you have the choice, high Kv + high gearing is the way to go
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Well explained! I assume that switching from 149kv 3500w to 192kv 4400w motor would shorten my range on the board though? Or would this just be the case during heavy riding?
They should not use much more power just going regular speed.
Change your gear ratio first for more top speed and increase motor amps for low speed torque increase.
If the motors get too hot and or the acceleration is not enough you will need bigger motors not just kv change.
Okay, my motor amps are already at 80a per motor so that’s maxed out. However the battery max per vesc is set tp 45a max. Shouldnt that mean that my motors cant get more than 45a each anyhow? As you see im a newbie in building eboards and i followed a guide to set the values that i have.
My motors are not getting very hot at all atm, im in sweden though and outside temp has been around 5°C since i started riding the board.
Not really, battery amps limits max system power. Motor power is not directly linked to battery amps as the voltage changes with speed.
Like 40 battery amps, 40 amp X 50 volts = 2000 watts. Is max system power.
But at slow speeds the motor is at much lower voltage.
Like 2000w / 80amps = 25 volts. Or go even slower and the 80amps starts to limit power, at 12.5 volts X 80 amps = 1000w Slower still 6vX80a=480 watts. So you see at slow speed motor amps limits torque.
As you pic up speed it starts to even out.
People say motor amps effect slow speed torque “mostly” and battery amps effect high speed torque “mostly”.
Temperature is the only real limitation for BLDC motors, your lucky to have low temps outside. Lower your gear ratio and increase motor amps till your motors get too hot then turn it down a bit. If you want more torque AND more speed bigger motors is pretty much the only way. Or higher voltage but that might just make the motors hotter which means you need a bigger motor. Around 60c is ok operating temperature, which is quite hot to the touch. 80c or over is probably shortening their life.
So you mean that i can increase the motor amps to more than 80a even though that is the rated max? Just keep an eye on the temperature so that it doesnt get to hot?
Hmm i thought that the voltage was constant from the battery through the system, interesting.
Yes you can. The max in reality is dependent on how long your at that load, ambient temp etc etc. monitoring temps and testing is the only way to find the actual limit.
The voltage from the battery to the esc is constant, then esc modulates it to control rpm and torque.
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Mostly with this stuff, it’s a spray grease which is thin and gets thicker after a short time and it’s white.
Once I used plenty of thick black Lithium grease but that wasn’t funny to remove from black gears. It was more silent for the first minutes but then sticked more to the housing than the gears.
I prefer spray grease because you can apply it as often as you like. Thanks for reminding me to do that today . I was riding 140km since the last time and it feels a bit smoother after re-greasing. Normally I add a bit grease each 100km.
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