Some info on arduino, if youre fully rolling your own code, you can do whatever you want, but if you’re planning to use the internal balance app built into the controller firmware itself (see I didn’t say VESC, you’re welcome Frank!), then you wont be able to use an arduino. The 4.12 needs the rx/tx pins to communicate with an IMU (bmi160) on i2c so you wont be able to get any info out that way. If you get a controller with an onboard IMU, then you can use rx/tx for a bluetooth controller or your arduino, but you’d have to choose. You can get a uart multiplexer (usplit?) ive never tried one, but i think it would let you do both bluetooth and arduino (you still cant mix i2c imu tho). However i would recommend getting a blue pill chip which is arduino compatible and supposedly supports can bus. Then you can get your data for your screen over can bus, keeping the rx/tx lines free. I’m planning on building a companion codebase for the balance app using this method at some point for screens/leds/beepers/etc at some point, but i have no timeline for it, its just an idea.
Hi NuRxG!
Thanks for the suggestion on CAN Bus!
I already figured that arduino and an external IMU wouldn’t work simultaneously. So my plan was to try the balance app and use the arduino in the beginning only for battery level (“proof of concept”). Then I’ll either try to run balancing code on the arduino or get a controller with built in IMU.
Probably I’ll code myself a balance app because I want to try if it makes sense to be able to set an offset to the IMU value - so the idea is to manually make the boards “level” parallel to the ground while riding up or downhill for a while (more space between front or rear to the ground while riding)… I don’t know if it’s a dumb idea but I definitely want to try it
Do I understand that right? higher rated erpm means it’s better protected against voltage spikes while regenerative operation?
Erpm is the number of magnets passing over the stator, so 100 magnets at 10RPM is 1000ERPM
The vesc 4 hardware will fail sooner than a vesc 6 due to the lower ERPM limit (assuming you can reach said ERPM limit)
The balance app has the option to angle the nose up or down if you wish (constant tiltback). Hill detection is not so simple, i’ve pondered adding 1 or 2 distance sensors to the nose/tail, but things like curb drops can mess with it. Overall hill’s aren’t really a huge problem, and the I term can be used to kinda sorta maybe a little do the same exact thing.
From a riding perspective, even if you did want some extra angling for uphill, matching the hill angle would be too much, and when going downhill I think trying to break while the board is nose down would be quite scary.
Well the first, and not the second. But also another, third reason and a fourth reason.
I would prefer not to run 13S on most 60V ESCs, but never, ever would I do it on a 4.12.
VESC 4.12 controllers are great in isolated instances, like dual drive 10S budget skates for example. Folks have been using VESC 4.12 for years and if you don’t try to exceed their abilities, they work pretty darn well.
But on a single drive, and especially a single drive balance vehicle, a 4.12 will be a very poor choice – as despite having relatively good peak/instantaneous performance, their continuous performance is poor at around 15A sustained (in my experiences) and their FETs don’t really have any way to add heatsink abilities as they dump the heat on the PCB side of the FETs instead of the topside. So the vehicle could go into thermal throttling and have terrible performance after about 25 seconds of working really awesome. Every single time you power it on.
The fourth reason is that they don’t have an IMU.
I haven’t hit it yet, but i believe it will start to feel as if your max current is lower.
@NuRxG I was thinking exactly the same… but I don’t want that it automatically detects and adjusts… I want to be able to adjust the angle manually in 1° increments. I also figured that if the hill is very steep and the board will be completely parallel to the ground riding could become quite uncomfortable…
@Fosterqc I understood that there’s a max erpm and that it’s lower on 4.12 based controllers… I don’t know if I understood everything right but I didn’t really think it could be a problem on a motor with kv ~10… I mean, max erpm would be 60000 right? And the motor max speed would be under 600… so I don’t know how much magnets the motor actually has, but alone from this values it could have up to 100 magnet pairs and would still be fine with max erpm on 4.12? Am I missing something? I think I read on a vesc configuration of a similiar project with the same motor that it has 14 poles…
@b264 do you think I’ll need more than 15A continous? I thought that it might have spikes but would usually run at significantly lower power? probably I should’ve thought of the worst case - going up a hill
lol it prob has around 60 magnets, you can find pics of them taken apart in the threads or on telegram
TBH it will be ok-ish most likely but almost everyone uses a VESC 6
VESC is the one thing you don’t cheap out on quality, even the good ones can break.
I mean, I get it, don’t go cheap, but I’m on a low budget and expect to wreck at least one anyways…
I count 30 - so 15 poles right? I’m completely confused by now
Pole pairs is something else ERPM is every magnet.
sorry idk where I just got 60 from then lol.
You should get a cheap focer, EU folks can get one to you for less than 80e
Is it every magnet?
I just read this on erpm: https://vesc-project.com/node/183
Technically you are right, there are really 60 magnets in the picture 
Yeah I think I just do that… they already shipped the 4.12 based one… I guess there’s nothing wrong in having one around
single drive sk8 time, really enjoying mine.
Yes, if you want to go up a hill. Also the worst case scenario for an esk8 is far different than the worst case scenario for a balance vehicle.
Overbuild it, plan for worse, enjoy the good results.
Gah. my brian 
Just to add my two cents and some experience to this, yes you do! And not just because you need that continuous for hills, but because you need the low internal resistance it implies for the peaks. A onewheel benefits massively from having that peak power for dealing with whatever tries to throw the rider like kerbs, unseen big pine cones, sudden elevation changes or just fast rider movements. The sub-second reaction stuff. At low speed that is largely limited by the battery and its voltage sag. Mine pulls 2kW peaks in such situations.
My old pack couldn’t really do it. 3p of LG M29 was good for ~18A continuous and 30A peak. Think what happens to it when you go off balance and the board does it’s darnest to correct for that. It pulls more current, causing voltage to sag. That causes it to draw even more current for any given power. Which causes the voltage to sag some more. Repeat and notice that pulling more current won’t get you much if any more power due to the voltage sag 
This caused a few nosedives, especially when the battery started getting low. And you can’t compensate much by riding, as shifting your weight back means pushing the front down, something the board again needs power to resist. If you don’t have that you get a nosedive.
The new pack made of 3p VTC6’s fixed that completely. While both packs meet the continuous power requirement, even up hills, I found out that it was the peak which was more limiting. In my opinion you want that low internal resistance for these, you really do.
Hey @Jopj
Thanks for the input!
The 15A continously wasn’t really about the batteries, the whole conversation was just about the vesc 4.12 based controller.
Battery-wise I planned to go either with LG HE4 or with Sony VTC4, so I thought that shouldn’t be a problem?
I thought of building just 1 pack (12S2P) in the beginning and adding a second when I feel that I need to.
You’re getting me thinking I should do that right away…
The 2P VTC4 would certainly work since it’s a very high current cell. (Mayhaps you are looking at those nkon.nl refurbished VTC4:s 
). I’m a firm believer of packing as much battery as humanely possible into anything, so if you have the budget and a way to parallel two of them safely I’d surely go for it 