you do realize that 12s is 50.4v, that will kill a 48v motor.
The motor is rated at about 15amps, 30 amps is not good
That shouldnât be a problem since we can calculate the gyroscopes distance relative to the ground (on a flat surface) if we use a little bit of trigonometry. We can then calculate the actual distance to the ground using the ultrasonic sensor (which is relative to the position of the gyroscope which is relative to the ground).
Even if we donât want to use the ultrasonic sensor, I think this equation is important as we could use it to implement a âpushbackâ feature (although instead of doing all the math you could just measure the gyroscope angle while positioning the tip of the board against the ground to calibrate it, but this would only work on flat surfaces).
However, if you do all the math I think you could interpolate the ultrasonic sensor readings to get the angle of the ground (measured from the tip of the board to the center). You could give a warning if the angle of the ground approaches a certain value (as you can now measure the exact distance of the nose of the board to the ground) or even allow the board to tilt back within a certain range to avoid nose dive.
Iâm not sure how FM implements there version of pushback, but I think it may also be possible to calculate the angle of the ground by observing the amount of power delivered to the motor vs the current acceleration measured: http://trutechmotors.com/white-paper/wp-1-title/
Now that I think about it, we should probably start there and think about Ultrasonic sensors after we explore that method.
What version do you suggest 600W / 50v ?
12S(50V max, 43V average) seems a bit high for that motor and there is a high risk of wrecking the FOCBOX at 12S when relying on regenerative braking. A 10S battery system should be safe for both.
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The Onewheel has the pushback implemented in 3 ways, when you go up to 25 km/h, when the amps are increasing and getting close to the limit of capability of the battery to deliver more amps or volts to keep you balanced, and the last one when you reaching the limits of the motor, torque, revs/kv.
I think is easier to implement the pushback in that way than in the way with the ultrasonic sensor.
Actually I donât find it useful a sensor that reads the surface since one of the best things of the ow is the ability to go off road, 25 km on a flat and long road could be a bit boring 
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Thanks, this is very useful information. I didnât even consider factors such as capability of battery. You could also limit speed when the battery drops below a certain % to help extended the lifetime of the cells. I donât think any current DIY OneWheel firmware (the Arduino, NAZE32 or VESC6 codebases) implements a pushback feature and is certainly a very important safety feature to have.
In my eyes, once the firmware is feature complete the main issue of DIY builds will be the rails. I donât think wood rails are a good solution long term with the amount of stress the motor produces via torque (not to mention going off jumps, etc.) and think that the aluminum CNC milled rails like the OneWheel uses are the way forward. Unfortunately, not a lot of people have access to CNC tools to build something like that and I donât think there are any open source blueprints for them. I asked about fitting OEM XR rails to this motor earlier but havenât had a response back yet (I suspect most people simply donât have the parts to test).
You canât limit the speed on a ow the rider has to swift the weight before limit the speed if so instantly nosediving will happen. I own a ow but my idea was to go DIY, just are too many things out of my hand, coding is one of the most important things to fine tune the wheel that I canât do. The wheel of the hub motor available is 10", ow uses 11" difficult to find wheels that fit in there, and the wheel is one of the more important part that gives you stability, carving⌠And there is quite a lot of tested options with kart wheels with different properties, better for carving, less stability and so on. P.s the spare parts of ow are stupid expensive, the CNC rails are close to 300 dollars!!! I think the wooden rails are just fine for prototyping
well 18650 batteries are 3,7V so that would mean 44,4V no?
@Relys the pushback isnt that advanced, a quick boost to push you offbalance backwards and then drop the speed right after the push.
@Surfer I was also thinking about the size differenceof the wheel, so Iâm considering to mount a shorter metal base about the width of the wheel and the mount the full length rails a bit above the centerpoint of the wheel to get some more clearance from the ground
thatâs not true, brushless motors will work at any voltage (to a extent) until the voltage is high enough for the windings to arc you wonât have any issues, and even when the wingdings do arc it is not going to cause a cooked motor.
also 48v is nominal voltage, 48v usually stands for 13s, 13s fully charged is 54.6v
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Your bearings will crap out way before your windings are going to arcâŚ
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In the other thread some people did a group purchase of 10x of these 11 inch wheels: https://www.aliexpress.com/store/product/11inch-350w-500w-wide-tire-hub-motor-phub-44/1470068_32536443206.html?spm=2114.12010615.8148356.4.350c51f63QudcB
Less info on them in the listing compared to the 10 inch ones though.
This is simply not true.
The main limiting factor on brushless motors is amps which leads to overheating if the amps are too high. The amount of amps is relative to the load you put on your motor and esc settings. Voltage just controls max rpm.
Also a 12s battery under load will be closer to 45 - 48 volts, so the 48v ratting is actually 12s.
If its rated at 15a x 48v thats 720 watts. You could easily run it at 10a x 60v = 600 watts, it would run cooler. You would just lose some low speed torque in exchange for higher top speed.
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As long as the motor stays cool there is no problem. This only works with an Vesc that is constant currenting. An regular bldc controller would fry and motor by over volting it, beacuse it would instantly draw more amps than it can handle
Anyway⌠the 36V and 48V motor is the same 
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hahahah thats funny.
Want to join our whatts app? (me fungineers and a few others)
Unlikely.
We use the same type of outrunners in RC helicopters with 12s and more than double the kv without problems.
Edit: Cafeine has not kicked in yet. Just saw this is not about normal esk8 motors. Disregard my remark.
I think what @FredrikHems said is not falsified by your statement both can be true.
I think he is talking more like 1000 volts.
But I dont think its the bearings that break first. What happens first is the bell starts to expand, then becomes unbalanced, then explodes. There is a youtube video where the do that. I think the motor rpm is like 80k - 100k they explode.
They could probably go to 150k rpm if they were designed for that. Above that I think you need oil bearings.
Now I want to research highest rpm motors.
Edit, Found the video, explodes at 200k rpm. 
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