It all depends on the formula used, the geometry of the wheel (shaper edges vs rounded edges) and the pavement roughness. We’ve got some serious bad pavement here in Sydney which could be a reason none of these wheels hold up for a long time. Beta testing of the 100 mm Boas have shown some promising results and I am looking forward getting those for my new board. It would be great to see some longtime runs of the green 107mm Abecs, whether it’s just an issue of the geometry or whether the formula is to blame.
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…smelling like the Superfly demolition derby is paving the way for the Boa Hematox Esk8 raise.
What rear light is that? Looks awesome!
That’s the Meilan X5
How much you charging for the enclosure?
Inspired by your build. Used some spare parts I had lying around like deck, wheels and battery. Made it so friends can ride along
Did you do any sort of phase wire management to hold wires in place? What kind of bushings did you use?
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Beautiful Tito! That is the fastest board I had. I sold it because I had too many boards at the moment and because I needed a light board for short commutes, but now I miss the acceleration, speed and stability. I was going to build the moonshine sidekick with a small battery as a second light board besides the spud but I think I’m going to fit a double stack enclosure to fit a 12s6p, I don’t care if it will weight a lot, I realized fast boards are more fun.
I used riptide pivot cups and wfb bushings and it got a pretty nice turning radio and better stability at high speeds
Fast boards are definitely fun. My other board has 12s7p. Really heavy but nice having the range. Look forward to seeing your next build.
Oh yeah wfb, my favorite back when I had caliber IIs might give those another try. Thanks
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If battery Max is 40 how can the motor get 90?
Battery current = motor current * duty cycle
Duty cycle = (not exactly) %of unloaded speed
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Unloaded speed? What is that?
Top speed = 50km/h
10% duty = 5km/h
50% = 25km/h
And so on
I think that is what @Pedrodemio was meaning, if not correct me please
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Exactly
Things get interesting when you start to consider the current limits. Let’s say you have 30A battery max and 60A motor max and a top speed of 60km/h
This results in maximum torque up to 30km/h, then then torque has to drop to keep the battery current from going over 30A and you enter a stage of constant power
I’ve been working on a calculator that takes all of that in acount plus drag, rider weight, battery internal resistance and etc, just need a few more tweaks, the results are way more accurate than just assuming a efficiency of 80% or so and applying to the no load speed
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I get the duty cycle I can program PWM and so on. I just don’t get how you would push for example 100A from a 50A battery at 50% duty cycle.
This mean I would pull for exampe during 10ms 100A then 10ms off and again 100A 10ms correct ? But if doing calculations this would still be the same as outputing 50A but constant. And pulling 100A might start to detriorate the battery even for 10ms or am I still looking to it from the wrong angle ?
I also understand about the maximum torque that you just explained, you mean for the complete acceleration cycle I wil be enjoying the fully motor torque but when going from 30KM to 60km because I limit the current to 30A the motor starts to lose torque as it gains speed.Only thing is that I still can’t relate this to the above about having the motor pulling double the battery current.
Is there a post or a webpage explaining this more in detail ? I want to really understand it as I am going to configure my 2 vescs maybe in 3-4 weeks as my parts start to arrive.
Not exactly, the battery won’t be subject to more than the limit, you can’t think of the motor as a resistor since it also has inductance
The PWM will act as you said, some times on, some times off, but that happens at the switching frequency, 20 KHz by default, since the motor is also a inductor everything is smoothed out
What the PWM is modulate the voltage that is feed into the motor
The simplest way to understand is by conservation of power. Let’s say you are at 50% duty cycle and requiring the maximum current the motor can put out, 60A for example, also let’s say that the battery voltage is 30V, so at 50% duty cycle the motor is subject to 0.530 = 15 V, and the power is voltagecurrent = 15*60 = 900 W
Now to the battery, we need 900 W, at 30v that’s power/voltage = 900/30 = 30 A
So let’s say the motor I have is 60A like you said. If I have max speed of 30kmh I only get max torque until 15kmh since battery only 30A.
But I don’t get it because if I use lower gears I should have much more torque or not? You mean torque directly at the motor? Or at the wheel?
Basically if my battery is a limiting factor should I just program for speed for example for 120kmh then I would always have max torque until 60kmh. I think something I still don’t totally get it.
If this is true then both configs (30kmh and 120kmh) should be both at max torque at 15kmh so what makes the difference here is the gears, at 15km with 30kmh max speed the wheels would have much more torque because of gears and at 120kmh much less because the gears would be small but both using the max. Motor torque correct?
So resuming if my battery has only half the current of my motor I will always be getting only the % of torque past a given % of speed. So even if I have a really big motor but low bat voltage I can only enjoy the big acceleration during a small percentage of the speed. So now I am thinking, depending of the max bat current I have there is an optimal motor to be using or? Not always big is better.
And sorry for spamming the thread 
Correct
If you keep the current limit the same, the torque at the motor will be the same, if you increase your gear ratio, you will have more torque at the wheel but your top speed will be lower and the maximum speed for max torque will also be lower
What dou you mean by program top speed? Top speed is determined by motor Kv, battery voltage, gear ratio and wheel diameter
If you you would gear a board for 120 Km/h and using the 60A motor limit and the 30A battery limit, indeed you would have max torque up to 60 km/h but this max torque would be way lower than if you geared for 30 km/h
Exactly, if you want full torque across all speeds you need the battery current be equal to the summed current of all motors
All depends on what you want, I run dual 5055 motors with 40 A each and 30A total battery current, I have full torque up to 17 km/h and for me it’s ok
Thank you now I get it, I meant to say design and not program The board eboosted design looks amazing. I am currently building my first DIY based on his design. I think I will open a thread too. This was great here for inspiration.
For those who enjoyed the build thread, here is the latest facelift:
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