Message to Traditional (pedal) Unicyclists Thinking of Going Electric

[andrew900nyc]

My first EUC (MTen3) arrived two days ago. Having read lots of posts on the forum about learning to ride a EUC, I figured it wouldn't be too steep a learning curve for me, but I also figured it would take me a decent amount of practice to master the basics. I was completely wrong. Apparently skills obtained from pedal unicycling do carry over to EUC's quite well because I had nearly no learning curve whatsover. Within the first ten minutes, I was riding at slow and moderate speeds, turning with no problems, slow speed maneuvering with no problems, and free mounting fairly consistently (though sloppily and with inaccurate foot placement on the pedals, so I definitely need to improve on this). By day two I was idling a bit, but had concerns about the stress it could cause the motor/electronics, so I stopped and then found out from a reputable source that idling on the MTen3 (particularly at my current weight) isn't a good idea. I'll be ordering an MSX soon and have been informed that idling on the MSX isn't problematic. In any case, I am sharing this information to let any traditional unicyclists know that they will not have any problems whatsoever learning how to ride an EUC quickly (or possibly instantly). So if you are a pedal unicyclist thinking about going electric, I highly recommend that you do! Since traditional unicyclists already have most of the skills, it's kind of like going from a bicycle to a motorized mini bike. The transition is super easy. Even if you plan to stay active as a pedal unicyclist, having an EUC in your collection is definitely a good idea!   

[meepmeepmayer]

If you can walk (pedal unicycle), you can crawl (EUC)

[andrew900nyc]

3 hours ago, meepmeepmayer said:

If you can walk (pedal unicycle), you can crawl (EUC)

Now that's the message I'd like to convey to the pedal unicycle community! 

I wonder what percentage of pedal unicyclists know that EUC's have evolved from wheels with performance on par with hoverboards to incredibly capable machines that could be better compared with high-performance eScooters. I, for one, had no idea until fairly recently. I think there could be a decent amount of potential EUC riders among pedal unicyclists. 

[Mono]

9 hours ago, andrew900nyc said:

I am sharing this information to let any traditional unicyclists know that they will not have any problems whatsoever learning how to ride an EUC quickly (or possibly instantly).

I had no doubts about that. Unfortunately it's not the other way around 

[null]

Just to say I concur with OP,
I have no special balance abilities but was up and (roughly) riding the EUC in ten minutes from doing classic unicycle in my teens.
Friend of my mom just had the same experience, at close to 60 she got it real quick.

Edited June 1, 2019 by Mimolette

[LucasD]

On 5/30/2019 at 11:52 PM, andrew900nyc said:

My first EUC (MTen3) arrived two days ago. Having read lots of posts on the forum about learning to ride a EUC, I figured it wouldn't be too steep a learning curve for me, but I also figured it would take me a decent amount of practice to master the basics. I was completely wrong. Apparently skills obtained from pedal unicycling do carry over to EUC's quite well because I had nearly no learning curve whatsover. Within the first ten minutes, I was riding at slow and moderate speeds, turning with no problems, slow speed maneuvering with no problems, and free mounting fairly consistently (though sloppily and with inaccurate foot placement on the pedals, so I definitely need to improve on this). By day two I was idling a bit, but had concerns about the stress it could cause the motor/electronics, so I stopped and then found out from a reputable source that idling on the MTen3 (particularly at my current weight) isn't a good idea. I'll be ordering an MSX soon and have been informed that idling on the MSX isn't problematic. In any case, I am sharing this information to let any traditional unicyclists know that they will not have any problems whatsoever learning how to ride an EUC quickly (or possibly instantly). So if you are a pedal unicyclist thinking about going electric, I highly recommend that you do! Since traditional unicyclists already have most of the skills, it's kind of like going from a bicycle to a motorized mini bike. The transition is super easy. Even if you plan to stay active as a pedal unicyclist, having an EUC in your collection is definitely a good idea!   

How much you weight that you think idling is posing problem?

Especially that Mten3 is quite powerful and has a lot of torque  

[andrew900nyc]

On 5/31/2019 at 5:13 AM, Mimolette said:

Just to say I concur with OP,
I have no special balance abilities but was up and (roughly) riding the EUC in ten minutes from doing classic unicycle in my teens.
Friend of my mom just had the same experience, at close to 60 she got it real quick.

I'm glad to hear that other other pedal unicyclists have had the same experience that I had. I believe most pedal unicyclists are very likely to have this same experience. As such, I think it's important that this information is (hopefully) easy to discover so that any prospective pedal unicyclists will feel encouraged to get a EUC and will be able to make an informed decision regarding which one to purchase.

If I had known I would be able to just hop on these things and ride and turn and learn all the basics within minutes, I probably would have just skipped the MTen3 and gone straight to the MSX. If there are any forum members who can present some compelling reasons why it's good to have a lower performance, smaller wheel in addition to a high-end wheel, I will be most appreciative because maybe then I won't feel that I may not have made a very smart choice. As of now, I'm trying to convince myself that (1) the smaller wheel will somehow help me develop better skills than just having the larger wheel alone, and that (2) I'm much better off allowing any interested friends to try my MTen3 rather than my MSX. Perhaps those are good enough reasons and I should just allow myself to feel convinced based on those two justifications rather than second guessing myself. 

[LucasD]

Anybody will tell you that Mten3 is harder to learn than any other wheel?

Mten3 is trickster wheel or slalom equivalent from ski. MSX is like giant ski.

Two wheels for totally different purposes (one totally agile, second stable at speed)...

Edited June 1, 2019 by LucasD

[andrew900nyc]

7 hours ago, LucasD said:

How much you weight that you think idling is posing problem?

Especially that Mten3 is quite powerful and has a lot of torque  

Unfortunately, I'm currently 210 lbs, which is 25 lbs above my normal weight. I'm in the process of slimming down, but even at 185 lbs I don't think idling on the MTen3 is a good idea.

Despite the MTen3's impressive capabilities, I was informed that idling could cause the mosfets to burn out. 

[LucasD]

2 minutes ago, andrew900nyc said:

Unfortunately, I'm currently 210 lbs, which is 25 lbs above my normal weight. I'm in the process of slimming down, but even at 185 lbs I don't think idling on the MTen3 is a good idea.

Despite the MTen3's impressive capabilities, I was informed that idling could cause the mosfets to burn out. 

I think the mten3 has mosfets (or control board to be precise) from Tesla so no frying possible, though Marty has fried battery, but I think they fixed it already...

[andrew900nyc]

2 minutes ago, LucasD said:

Anybody will tell you that Mten3 is harder to learn than any other wheel?

Mten3 is trickster wheel or slalom equivalent from ski. MSX is like giant ski.

Two wheels for totally different purposes (one totally agile, second stable at speed)...

Thanks! I'm feeling better about having two wheels already!

Glad to hear they are opposite ends of the spectrum. Having only ridden the MTen3 so far, I have nothing to compare it to, but I can visualize your description of the differences and now I think it probably makes good sense for me to have both wheels! 

[esaj]

18 hours ago, LucasD said:

How much you weight that you think idling is posing problem?

Especially that Mten3 is quite powerful and has a lot of torque  

The motor has lowest back-EMF voltage at standstill, the faster it rotates, the higher voltage the motor itself will generate. For this reason, given a stable input voltage (from the battery, of course in real life it does drop somewhat the more current is being drawn), the current and torque are highest at standstill ("stall torque"). At maximum no-load speed (ie. the motor turning freely, like holding the wheel in the air), the back-EMF will reach the battery voltage, and no more current can flow because there's no voltage difference, thus no torque and no more acceleration is possible.

 

When idling back and forth, the motor comes to a stop before starting to rotate the other way around, at which point the maximum current will flow through it to get it moving again. The momentary power draw of the motor is at its highest and things heat up. @Jason McNeil made a video with a thermal cam years ago showing how the mainboard mosfets, capacitors and the motor phase wires heat up idling back and forth:

 

Off the top off my head, I don't recall anyone ever managing to burn their board through idling (doesn't mean it never happened), but it could force you off due to overheating. Also the batteries might get hot with repeated high current draw, if there are less packs in parallel. The motors likely have enough thermal mass to dissipate the heat by themselves, at least I'd think burning the motor would be pretty difficult, unless it's stuck (cannot rotate) and the board tries to drive it continuously at full current (still, I'd think the fets would burn before the motor).

 

Edited June 2, 2019 by esaj

[TomOnWheels]

54 minutes ago, esaj said:

The motor has lowest back-EMF voltage at standstill, the faster it rotates, the higher voltage the motor itself will generate. For this reason, given a stable input voltage (from the battery, of course in real life it does drop somewhat the more current is being drawn), the current and torque are highest at standstill ("stall torque"). At maximum no-load speed (ie. the motor turning freely, like holding the wheel in the air), the back-EMF will reach the battery voltage, and no more current can flow because there's no voltage difference, thus no torque and no more acceleration is possible.

 

When idling back and forth, the motor comes to a stop before starting to rotate the other way around, at which point the maximum current will flow through it to get it moving again. The momentary power draw of the motor is at its highest and things heat up. @Jason McNeil made a video with a thermal cam years ago showing how the mainboard mosfets, capacitors and the motor phase wires heat up idling back and forth:

 

Off the top off my head, I don't recall anyone ever managing to burn their board through idling (doesn't mean it never happened), but it could force you off due to overheating. Also the batteries might get hot with repeated high current draw, if there are less packs in parallel. The motors likely have enough thermal mass to dissipate the heat by themselves, at least I'd think burning the motor would be pretty difficult, unless it's stuck (cannot rotate) and the board tries to drive it continuously at full current (still, I'd think the fets would burn before the motor).

 

@esaj I can tell you that the tire will probably take fire, before the motor will burn... This is what happens to me with ks18L and lock issue. It was smelling burned tire and plastic and you can barely touch the metallic part of the wheel...(I think at that point, magnets are loosing their efficiency and so the motor will be indeed dead....)

[esaj]

34 minutes ago, TomOnWheels said:

@esaj I can tell you that the tire will probably take fire, before the motor will burn... This is what happens to me with ks18L and lock issue. It was smelling burned tire and plastic and you can barely touch the metallic part of the wheel...(I think at that point, magnets are loosing their efficiency and so the motor will be indeed dead....)

True that, there were the cases of locking up KS18(X?)Ls, where the mainboard tried to keep driving the motor (apparently only a single phase since the motor didn't move but locked up?). Apparently not high enough current to burn the mosfets (low duty cycle?), but caused considerable heating of mainboard, wiring, batteries, motor... The permanent magnets might lose their magnetization if they heat up enough? I don't know enough about magnetic fields or electric motors to say what happens if/when the motor coils reach saturation currents... probably nothing good, it becomes an induction heater for the inductor cores or something?

And of course my explanation above is a gross simplification overall, the back-EMF is not a constant DC voltage, but more like an AC sine wave, the duty cycle at getting going from stand still is probably not 100% (the gate drivers likely aren't even capable of 100% duty cycle, as the boot strap on high-side N-channel fets needs to be pulsed to keep the gate voltage high enough) so the current is at least somewhat limited etc... still the basic idea (highest currents occur starting rotation from stand still, and cause high losses with significant heating) should be correct, at least to my knowledge.

[TomOnWheels]

6 hours ago, esaj said:

True that, there were the cases of locking up KS18(X?)Ls, where the mainboard tried to keep driving the motor (apparently only a single phase since the motor didn't move but locked up?). Apparently not high enough current to burn the mosfets (low duty cycle?), but caused considerable heating of mainboard, wiring, batteries, motor... The permanent magnets might lose their magnetization if they heat up enough? I don't know enough about magnetic fields or electric motors to say what happens if/when the motor coils reach saturation currents... probably nothing good, it becomes an induction heater for the inductor cores or something?

And of course my explanation above is a gross simplification overall, the back-EMF is not a constant DC voltage, but more like an AC sine wave, the duty cycle at getting going from stand still is probably not 100% (the gate drivers likely aren't even capable of 100% duty cycle, as the boot strap on high-side N-channel fets needs to be pulsed to keep the gate voltage high enough) so the current is at least somewhat limited etc... still the basic idea (highest currents occur starting rotation from stand still, and cause high losses with significant heating) should be correct, at least to my knowledge.

https://www.supermagnete.de/eng/faq/What-temperatures-can-magnets-sustain

I just remember that when it happens to me I asked KS if there will be now any issue with the motor and they told me that under 130°C it's ok. But well I read quite a lot documentation on the net and it's pretty clear that magnets will suffer from heat... And that it depends which class of neodymium they are.. which of course I don't know and KS won't tells me...