When will Begode make a 168V wheel?

[Planemo]

You're kidding right? Plenty of exposed places on most boards to get a belt from. Battery connectors are the least of your worries. The problem with 100v+ is it's enough to bridge gaps (or skin).

I admire your optimism about the electrical knowledge of the general public

 

[The Brahan Seer]

29 minutes ago, Planemo said:

168v+ gets into fairly serious high voltage handling skills.

Thats a very good point. The H&SE here says anything over 110V DC can be fatal. Others quoting 120V onwards. So perhaps we are already at the limit. 

Electric cars are roughly 650V and the training, skills and correct tools start to really matter.

 

 

[Funky]

13 minutes ago, Planemo said:

You're kidding right? Plenty of exposed places on most boards to get a belt from. Battery connectors are the least of your worries. The problem with 100v+ is it's enough to bridge gaps (or skin).

I admire your optimism about the electrical knowledge of the general public

 

I did say "good design".... Aka you should not even go anywhere near motherboard to do a tire change.

Any wires coming from motor - should connect somewhere in middle, not right into motherboard.

 

Still people should know while batteries are connected to wheel. And caps aren't "unloaded". You should act like it's a BOMB, that could go off any moment.

Edited July 14, 2023 by Funky

[Cerbera]

7 hours ago, Funky said:

I hope that 100kg 400V wheel can fly... Then maybe yes? (By fly - i mean literally fly.. Not to ride on ground.)

Now THAT would be a proper landmark moment when we get the technology to make PEVs fly... sadly I don't think that will be anytime soon, or even in my lifetime.

But EUC is the closest thing we have to that sort of feeling so far, so it will have to do for now !

[Cerbera]

6 hours ago, Robse said:

I am pretty sure Begode will come up with something 168 volts soon.  Not because anyone need it, but because they can do it 😁

Ah, the old Jurassic Park analogy again  We (the human race) will do stuff as soon as we can, with almost zero thought put into whether we should or not !

Our own vaulting ambition is also our biggest curse...

[0000]

For anyone taking up DIY EUC repair without an electrical background, I'd recommend reading the wiki entry on Electrical Injuries for a brief on all the factors involved.

There is no absolute threshold at a given voltage limit that can predict certain injury or certain death, although...

Quote

High voltage (over about 600 volts). In addition to greater current flow, high voltage may cause dielectric breakdown at the skin, thus lowering skin resistance and allowing further increased current flow.

... it's always a moving target though. What you want to do is always make sure your body never creates a pathway that completes an electrical circuit, especially given how little current it takes to cause harm and death. So practically speaking and in a nutshell, higher voltages increase the potential for electrocution, particularly if you decide to go mucking around with the internals while the electrical system is live (batteries connected).

As for the higher voltage wheels -

From a design perspective and for a given volume of space, a designer can decide whether to prioritize the number of cells in series for higher rpm/top-speed (without field weakening) vs the number of cells in parallel for larger overall capacity and thus range. It's a balancing act. Of course they could just keep throwing more cells at the design, but it would be making for a heavier pack(s) and a larger wheel at higher cost to the customer. The more cells you want in series, the more cells you'll need to populate each parallel group for capacity.

Also, consider the fact that wind resistance increasing exponentially with speed. A standing rider atop a wheel is in no way aerodynamic meaning higher average speeds necessitate larger capacity batteries and heavier wheels with large volumes for all these batteries. The point is, for the battery tech available, there's a bunch of trade-offs an EUC designer has to contend with and there's a happy medium to be had between top speed, weight of the wheel, range, and cost for each use case.

---

Hot take time

Personally, I like the 24S or 100.8V as a hard limit for the EUC format in general. Admittedly it's totally arbitrary, even from a safety point of view, but I think super high voltages (highway speed wheels) don't serve our hobby in the long run primarily for the reason that more and more people will be using them as motorcycles in traffic, and this will ultimately result in a total market/country wide ban. Honestly I can't see this as being anything other than a matter of time at this point.

The longer EUCs stay under the radar and are designed with more reasonable speed limits, the longer people will have the freedom to, hopefully, use them responsibly. A manufacturing hard limit of 40 mph, or even 35 mph for example, wouldn't be the end of the world for the community. Some might even argue 28 mph to be consistent federal ebike class 3 regulations here in the US. That said, I don't believe EUCs as a format of transportation will ever be made legal for use on public roads because of the ever-present possibility of the failure mode resulting in a cut-out that can leave the rider prone or helpless to avoid being run over.

I think it would be far wiser to admonish the manufacturers who are selling these high voltage/highway speed wheels, or at least not buy them, as short-term current market driven thinking will likely end up destroying the entire market altogether (bans), a timeline accelerated by selling these highly capable wheels. It's simply the technical limitation issue - EUCs can never feasibly be recognized as road legal for as long as an electrical failure can result in a motor cut-out (something inherent to the design). The more they are used this way, the closer this inevitability becomes in all of our respective regions.

Edited July 14, 2023 by Vanturion

[Robse]

6 minutes ago, Vanturion said:

For anyone taking up DIY EUC repair without an electrical background, I'd recommend reading the wiki entry on Electrical Injuries for a brief on all the factors involved.

There is no absolute threshold at a given voltage limit can cause injury or certain death, although...

... it's always a moving target though. What you want to do is always make sure your body never creates a pathway that completes an electrical circuit, especially given how little current it takes to cause harm and death. So practically speaking and in a nutshell, higher voltages increases the potential for electrocution, particularly if you decide to go mucking around with the internals while the electrical system is live (batteries connected).

As for the higher voltage wheels -

From a design perspective and for a given volume of space, a designer can decide whether to prioritize the number of cells in series for higher rpm/top-speed (without field weakening) vs the number of cells in parallel for larger overall capacity and thus range. It's a balancing act. Of course they could just keep throwing more cells at the design, but it would be making for a heavier pack(s) and a larger wheel at higher cost to the customer. The more cells you want in series, the more cells you'll need to populate each parallel group for capacity.

Also, consider the fact that wind resistance increasing exponentially with speed. A standing rider atop a wheel is in no way aerodynamic meaning higher average speeds necessitate larger capacity batteries and heavier wheels with large volumes for all these batteries. The point is, for the battery tech available, there's a bunch of trade-offs an EUC designer has to contend with and there's a happy medium to be had between top speed, weight of the wheel, range, and cost for each use case.

---

Hot take time

Personally, I like the 24S or 100.8V as a hard limit for the EUC format in general. Admittedly it's totally arbitrary, even from a safety point of view, but I think super high voltages (highway speed wheels) don't serve our hobby in the long run primarily for the reason that more and more people will be using them as motorcycles in traffic, and this will ultimately result in a total market/country wide ban. Honestly I can't see this as being anything other than a matter of time at this point.

The longer EUCs stay under the radar and are designed with more reasonable speed limits, the longer people will have the freedom to, hopefully, use them responsibly. A manufacturing hard limit 40 mph, or even 35 mph for example wouldn't be the end of the world for the community. Some might even argue 28 mph to be consistent federal ebike class 3 regulations here in the US. That said, I don't believe EUCs as a format of transportation will ever be made legal for use on public roads because of the ever-present possibility of the failure mode resulting in a cut-out that can leave the rider prone or helpless to avoid being run over.

I think it would be far wiser to admonish the manufacturers who are selling these high voltage/highway speed wheels, or at least not buy them, as short-term current market driven thinking will likely end up destroying the entire market altogether (bans), a timeline accelerated by selling these highly capable wheels. It's simply the technical limitation issue - EUCs can never feasibly be recognized as road legal for as long as an electrical failure can result in a motor cut-out (something inherent to the design). The more they are used this way, the closer this inevitability becomes in all of our respective regions.

thank u for this text 👍, i was about to write something nearly identical, but my "danglish' makes me a rather slow writer, and now there's no need for my text🙂

[Funky]

5 hours ago, Cerbera said:

Now THAT would be a proper landmark moment when we get the technology to make PEVs fly... sadly I don't think that will be anytime soon, or even in my lifetime.

But EUC is the closest thing we have to that sort of feeling so far, so it will have to do for now !

Well when EUC cut's out.. We are flying, at least for split second. So we are already there. 

[Eucner]

8 hours ago, Vanturion said:

From a design perspective and for a given volume of space, a designer can decide whether to prioritize the number of cells in series for higher rpm/top-speed (without field weakening) vs the number of cells in parallel for larger overall capacity and thus range. It's a balancing act. Of course they could just keep throwing more cells at the design, but it would be making for a heavier pack(s) and a larger wheel at higher cost to the customer. The more cells you want in series, the more cells you'll need to populate each parallel group for capacity.

You are missing the motor part. Combining higher voltage battery with lower kv motor can give exact same top speed with less electrical losses and same amount of cells.

[0000]

13 hours ago, Eucner said:

You are missing the motor part

Deliberately. I also didn't include the overall circumference of the tire affecting the torque vs rpm tradeoff, the total resistance of the packs coming primarily from the resistance in each cell resulting in voltage sag which is itself a tradeoff between top speed and capacity (range), voltage limits of the controller dependent upon selected component with limits vs cost, what else.

I didn't want to overcomplicate the explanation as the point was to illustrate the most relevant tradeoff to the thread topic: more cells in series = more cells required for each parallel group.

Edited July 15, 2023 by Vanturion

[Eucner]

12 hours ago, Vanturion said:

more cells in series = more cells required for each parallel group.

Only when voltage difference is low. For example 24s4p and 32s3p cell configurations give same performance with same amount of cells. The higher voltage system just has less losses.

[0000]

Fair enough, I was assuming in real world conditions the 32s rider would be riding at a higher average top speed on average than the 24s rider requiring more parallel groups to achieve a reasonable amount of range for this increased performance/speed capability. It doesn't have to be the case if you use motor windings to limit rpm/volt as you said. My original example wasn't thorough enough, thanks.

[alcatraz]

I welcome higher voltage. It won't bring more torque, but it should stretch the torque distribution further into a higher speed. That means you would maybe see free spin of 150km/h and you'll get more torque at 75km/h than with a lower voltage system (same motor) that free spins at 100km/h. But at 0km/h you have the same amount of torque.

[InfiniteWheelie]

PEVs should probably be kept as low voltage as possible, preferably under 50v (or at least under 100v).

Low voltage doesn't have to mean low performance, since motors can be wound for whatever speed you want regardless of voltage. I'm fairly sure you could have a 10kW wheel at just 48v without major issues. Thicker wires and perhaps some beefier electronic components to handle the extra amps. Maybe someone more knowledgeable can give better details about what's involved.

The current method seems to me like a convenience/cost saving approach, since they can reuse the same motors and increase performance over time by upping the voltage. It also saves money on copper wires (outside the motor). That said, I think higher voltages can probably be done safely, so I'm not totally apposed to it.

Edited July 22, 2023 by InfiniteWheelie

[chanman]

More current to get the same performance is generally not what you want, more copper to handle it is more expense and more weight. Look at electric car motors to see what we're approaching, 300V+.

[Planemo]

3 hours ago, InfiniteWheelie said:

 I'm fairly sure you could have a 10kW wheel at just 48v without major issues.

That would require over 200A.

Its fair to say thats a stretch.

[meepmeepmayer]

Higher voltage in a EUC is pretty much a free improvement (more speed, or more torque without losing speed for it), with less battery size flexibility as the only meaningful downside I can think of. Why would you not want it?

[InfiniteWheelie]

 

11 hours ago, Planemo said:

That would require over 200A.

Its fair to say thats a stretch.

Whoops that certainly is a stretch. Using a wire gauged calculator it shows 3/0 AWG which is massive. But here's an idea just for fun...

What if you made each half of the wheel entirely electrically redundant? Two 48v packs, two controllers, two sets of independent phases with 3 wires into each side of the axle. The two sets of phases could fire at the same time so each side would only need to carry 100a (3 AWG) which could possibly be small enough to wind.

This could provide very high safety with only 48v, and an entirely redundant powertrain (even down to the motor phases). When combined with high power cells, each side could temporarily provide the full 10kw so you can safely slow down or stop. It would them limit you to 5kw until the issue is fixed, so you don't overheat the motor.

 

10 hours ago, meepmeepmayer said:

Higher voltage in a EUC is pretty much a free improvement (more speed, or more torque without losing speed for it)

I don't think that's correct. Higher voltage on it's own doesn't give free anything (except lighter wires).

Maybe you're thinking of getting more voltage by adding more cells in series. By that same logic you can also get more amps by adding the same amount of extra cells in parallel instead, giving you either "more speed, or more torque without losing speed for it". It's not actually free though because you're adding extra cells.

Edited July 23, 2023 by InfiniteWheelie

[The Brahan Seer]

3 hours ago, InfiniteWheelie said:

This could provide very high safety with only 48v,

Not really. Although voltage is dangerous too, its current that kills.  DC Current kills >0.3 Amps.

 

https://www.electricaltechnology.org/2019/08/ac-dc-which-is-more-dangerous.html

Edited July 23, 2023 by The Brahan Seer
Added link

[meepmeepmayer]

7 hours ago, InfiniteWheelie said:

I don't think that's correct. Higher voltage on it's own doesn't give free anything (except lighter wires).

Maybe you're thinking of getting more voltage by adding more cells in series. By that same logic you can also get more amps by adding the same amount of extra cells in parallel instead, giving you either "more speed, or more torque without losing speed for it". It's not actually free though because you're adding extra cells.

You're right, it's not free overall. Batteries will have more cells and cost more, different electronics, etc.

What I mean by "free" is that, by increasing the voltage, you either get more top speed from an existing motor (but no torque loss because the motor is the same, after all) or you can wind your motor for more torque with the higher voltage cancelling out the top speed loss you would have otherwise. So "free" in the sense that you don't have to pay for speed with torque or vice versa, instead you simply increase the voltage.

For example, the 100V Begodes offered HS (high speed) and HT (high torque motors), and people had to choose. Then the first 134V wheel (Master) simply used the HT motor, and it was still fast enough thanks to the higher voltage.

In a general way, a higher voltage has those benefits but little to no downsides (forcing bigger batteries is a plus in my book, but obviously someone can disagree with that), so it is a "free" improvement in that sense. There's a reason EUC voltages (and power transmission voltages and electric car battery voltages and ...) tend to go up with time, not down.

Edited July 23, 2023 by meepmeepmayer

[InfiniteWheelie]

@meepmeepmayer But you’re adding more cells so it’s not free at all. Of course you don’t lose either speed or torque.

The real benefit of adding more series cells (voltage) is that you can always add more without needing to increase the wire diameter. If you add more parallel cells (amps) you’re adding more heat so you need bigger wires.

 

Edited July 23, 2023 by InfiniteWheelie

[EUCzero]

 

On 7/14/2023 at 11:11 PM, Funky said:

 How hard is not to touch "live" wires.. And not cross streams..

Also most (at least good design) have a plastic connector protecting pins.

Well. The controller board would also have the same voltage, and it is NOT protected with plastic.
You do know that the voltage from the batteries do not stop at the battery connector? But continues all the way.... from battery to the motor. So any part of the electronic can potential have that voltage.
Luckily DC voltage is not as bad as AC for our health. 

Edited July 23, 2023 by EUCzero

[alcatraz]

With three packs we could do 40S3P = 120 cells if they find a cell with a little more current.

That's a few cells fewer than the S22 and Master, but 168v.

I'd go out and say that you DO get more torque with higher voltage, but it's not over the entire speed range. It's actually where you want it = at the max speed of the previous generation (with lower voltage). This is using the same motor. Not heavier. 

Why? Because the torque-speed distribution has been stretched.

Edited July 23, 2023 by alcatraz

[Punxatawneyjoe]

1 hour ago, EUCzero said:

Luckily DC voltage is not as bad as AC for our health

well this simply isn't true. Ac voltage "alternates" and has a point that it reaches 0 volts 2 times a minute where as Dc voltage is constant. If you are struck by high voltage dc current you may not be able to pull away from it as you can ac.

Edited July 23, 2023 by Punxatawneyjoe

[Planemo]

6 hours ago, Punxatawneyjoe said:

well this simply isn't true. Ac voltage "alternates" and has a point that it reaches 0 volts 2 times a minute where as Dc voltage is constant. If you are struck by high voltage dc current you may not be able to pull away from it as you can ac.

AC voltage is usually 50Hz. Thats 50 times a second.