Speed Reduction Graph, Rider Info Needed

[Jason McNeil]

Working on a graphic to demonstrate at what battery levels Wheels will activate throttling from the max cruising speed in response to reduced battery voltage. Will be adding on other current models later, like the V5F & V8; offering a sample here for Community comment & feedback.  

1. All Wheels operate under the same principle of activating tilt-back at the programmed 'low battery' threshold.
2. This is supposed to be linear, a progressively reduced speed until a set minimum, in the case of KS, this is 12kph.
3. For Gotways, it's quite simple, all of their Wheels have the same firmware setting that starts to reduce the max speed, whether or not the tilt-back is enabled/disabled, at 30%.
4. Other factors like the max-power activation are not included for simplification. 

We need your help, if this chart does not reflect your actual experience of induced voltage speed reduction, please plot your data. This exercise will also be beneficial to providing evidence to certain manufacturers (cough, Inmotion ) to change their firmware on the V10/F to be inline with other models in the same class.  

[meepmeepmayer]

2 hours ago, Jason McNeil said:

For Gotways, it's quite simple, all of their Wheels have the same firmware setting that starts to reduce the max speed, whether or not the tilt-back is enabled/disabled, at 30%

Really?

I can only speak for my 1300Wh 84V ACM's (assembled April '17) behavior, but there it seems to be only voltage related.

The wheel starts battery beeping whenever the battery falls under 15% (so under a certain voltage). Which is about 30% under no load (wheel standing still and nothing on it - which becomes 15% under load with my 80kg weight). I get one slow beep at 15%, two slow beeps at 10%, 3 at 5%. Only at/towards 0% you get heavy tiltback.

I never noticed any speed reduction or speed related-alarms/tiltback with low battery. But of course I'd never have those if I slow down due to low battery beeps in the first place, so theoretically they might exist separately.

But effectively, as far as I know, at 30% no-load battery the Gotway wheel is at 15% under load and starts battery beeping and will force tiltback if you ignore the beeps and don't slow down/climb a hill/whatever and get to 0% battery voltage.

Edited April 4, 2019 by meepmeepmayer

[Marty Backe]

I'm kind of with @meepmeepmayer here.

All of my Gotway wheels only initiate beeping when the battery dips below 15% (load or no load, just 15%). And even then you can ignore it at your own peril.

The different Gotway wheels will initiate the 80% alarm at different speeds based on the wheel and the battery level. But none of them activate the tilt-back, at any battery level (except maybe at 1% ).

Of the wheels that I own, only KingSong and Ninebot will initiate tilt-back to slow you down below specific battery levels.

Edited April 4, 2019 by Marty Backe

[meepmeepmayer]

Technically the Gotway chart looks like this quality picture. And the constant top speed is only true if the 80% alarm doesn't cause reductions on its own (which, according to Marty, it does). Otherwise, it's a step chart where's some steps/ speed reductions at certain percentages.

But if the point is to convince Inmotion to improve their throttling behavior, focusing on Kingsong and not taking Gotway as an example might be better

How does the Ninebot One Z do it? You're no longer selling it, but it can still be a point of comparison from a probably rather safety-conscious brand.

35 minutes ago, Marty Backe said:

 

All of my Gotway wheels only initiate beeping when the battery dips below 15% (load or no load, just 15%).

You're right, 15% is 15%. It's just that it corresponds to about 30% no-load charge and Jason mentioned a supposed speed reduction at 30% and I figured maybe it's the same thing. Or maybe the 80% alarm lowers at 30%?

[Chriull]

@Jason McNeil: really great idea to put this speed over charge data in an overview chart!

Regarding the resoning/purpose/sensefullness of such limitations (Solution of Inmotion vs KS vs GW) here a chart for the KS16S:

Here is the maximum no load speed (~ lift cut off speed) and battery voltage added to your speed (tiltback speed) graph.

As one sees, the difference between tiltback speed and max no load speed gets less and less until 30 km/h - this means the safety margin gets lower and lower.

If one looks at some real driving data (for the KS16S) with the "max torque" over speed limit (here for the battery voltages of 63V (black) and 55V (blue). This was quite relaxed riding - mostly under ~25A reported...

As one sees here the maximum no load speed for the 63V where the black line cuts the speed axis = ~48 km/h as shown in the above excel graph. But as one sees here nicely, as soon as one drives faster (and accelerates a bit) the maximum reachable speed is much lower. With a current draw of ~20A and a battery voltage of 63V one could only reach some ~37-38 km/h. So an overlean is already waiting very near to the 35km/h tiltback speed!

So from a rational perspective a continous tiltback speed decrease parallel to the "maximum no load speed" would make sense - the safety margin would be constant over the whole battery range. Maybe for lower charges, like KS made for <30% this steeper decrease makes sense - as the batteries are not really performant at these levels anymore.

Edit: PS.: The tiltback limit for the V10/F seems to decrease faster than the max no load speed would (but hard to say exactly)

Edit2: the battery voltage is parallel ti thr max no load speed and easier to obtain - and shows by the difference to the tiltback speed line the available safety margin over the battery charge %

Edited April 4, 2019 by Chriull

[Marty Backe]

29 minutes ago, meepmeepmayer said:

Technically the Gotway chart looks like this quality picture. And the constant top speed is only true if the 80% alarm doesn't cause reductions on its own (which, according to Marty, it does). Otherwise, it's a step chart where's some steps/ speed reductions at certain percentages.

But if the point is to convince Inmotion to improve their throttling behavior, focusing on Kingsong and not taking Gotway as an example might be better

How does the Ninebot One Z do it? You're no longer selling it, but it can still be a point of comparison from a probably rather safety-conscious brand.

You're right, 15% is 15%. It's just that it corresponds to about 30% no-load charge and Jason mentioned a supposed speed reduction at 30% and I figured maybe it's the same thing. Or maybe the 80% alarm lowers at 30%?

The 80% alarm lowers at much higher number (>75%). I suspect it's a linear function that kicks in at some relatively high battery level. At least with the Tesla and all subsequent (ACM2, etc) wheels.

So I would modify your chart to replace the flat line with a shallow sloped line from 100 to 15%, and then the steep line. And to clarify, this plot is showing when the wheel will beep at you. The vertical axis represents wheel speed.

[Chriull]

A quick try of these tiltback limit graph with the battery voltage added. Afair the KS18XL goes down to 3V per cell? V10 and KS16S just till 3.3V?

As presumed, the V10F decreases tiltback speed faster than the battery voltage decreases and by this increases the safety margin with lower charge %.

For KSxx the safety margin decreases until the 30/25% battery level.

PS.: The safety margin (difference between battery voltage and tiltback speed) is relativ for each wheel and the differences do not qualify to compare the "absolute" safety margins between the wheels!

For this one would need to take the difference to the maximum no load speed (~lift cut off speed). Although this would be "almost" comparable - the steepness of the max torque over speed limit line is different for all this wheels and also influences the safety margin.

[Jason McNeil]

Update: Gotway/@Linnea Lin Gotway very kindly provided this overview of their programmed speed alerting characteristics. As @Marty Backe indicated, this 100-10% is not tilt-back, as with other manufacturers, but the level 3 audio alarms. It's interesting how Gotway permits the Rider to really push the Wheels to 80% of their max speed all the way down to where other manufacturers are limiting the cruising speed down to a snail's walking pace.  

On 4/4/2019 at 7:06 PM, Chriull said:

So from a rational perspective a continous tiltback speed decrease parallel to the "maximum no load speed" would make sense - the safety margin would be constant over the whole battery range. Maybe for lower charges, like KS made for <30% this steeper decrease makes sense - as the batteries are not really performant at these levels anymore.

With these 84v packs, with 6 parallels working in parallel, do you think there's an inherent (too great?) an unncessary safety margin which manufacturers such KS have not taken into adequate consideration when programming their larger capacity controllers degradation reductions? With the Gotways, we're not witnessing queues to ER wards as a result of the Wheels cutting out under low battery. 

Edited April 11, 2019 by Jason McNeil

[Chriull]

47 minutes ago, Jason McNeil said:

Update: Gotway/@Linnea Lin Gotway very kindly provided this overview of their programmed speed alerting characteristics. As @Marty Backe indicated, this 100-10% is not tilt-back, as with other manufacturers, but the level 3 audio alarms. It's interesting how Gotway permits the Rider to really push the Wheels to 80% of their max speed all the way down to where other manufacturers are limiting the cruising speed down to a snail's walking pace.  

Made an Update with the data for the Msuper X 84V 3rd Speed Alarm - Does the MSX84 allow discharge down to 3V or 3,3V per cell? I took 3,3V for now...

As one sees, the KS18XL allows some more speed than the MSX84V between ~45%-23%

 

47 minutes ago, Jason McNeil said:

With these 84v packs, with 6 parallels working in parallel, do you think there's an inherent (too great?) an unncessary safety margin which manufacturers such KS have not taken into adequate consideration when programming their larger capacity controllers degradation reductions?

Seems a bit overdone how they limit the speed for lower capacities... But to be honest i have no idea - one would need to test this! I just have my experiences from 2 parallel cells (ninebot one e+) and 4 parallel cells (KS16B and S)... And also this weaker feeling with these wheels at lower capacities could come from the controller - or just the limiting with tiltback...

The graphs of high current discharge (10A) from dampfakkus.de for LG MJ1/MH1 seem quite straight downto 3,0 V. They even "buckle" up a bit after this! -> a lower delta U over the same time with constant current would mean a lower internal resistance! * imagine here a smiley scratching his head with a puzzled look - could not find it in the list *

So from this (10A times 6 in parallel makes 60A in total) for battery current should make no special limiting necessary - with still enough reserve below the "hard limit" of 3.3/3.0V for sudden voltage sags...

But as said - i am not experience with li ion cells in "real live" conditions, dynamic (high) loads, etc... all my knowlege about them come from batteryuniversity.com and some other websites...

But tiltback (3rd alarm speed warning) is a very "inaccurate" safety measure anyhow - it is does not consider the wheels burden (acceleration/incline). So for "relaxed/careful" drivers the limits could be too restrictive and diehard drivers could never get any warning at all....

47 minutes ago, Jason McNeil said:

With the Gotways, we're not witnessing queues to A&E wards as a result of the Wheels cutting out under low battery. 

GW have a nice adoption make the alarm quite proportional to available speed and i'd assume GW drivers learn to respect their wheels limit or get used to fall "safely" 

 

[Nick McCutcheon]

4 hours ago, Jason McNeil said:

Update: Gotway/@Linnea Lin Gotway very kindly provided this overview of their programmed speed alerting characteristics. As @Marty Backe indicated, this 100-10% is not tilt-back, as with other manufacturers, but the level 3 audio alarms. It's interesting how Gotway permits the Rider to really push the Wheels to 80% of their max speed all the way down to where other manufacturers are limiting the cruising speed down to a snail's walking pace.  

With these 84v packs, with 6 parallels working in parallel, do you think there's an inherent (too great?) an unncessary safety margin which manufacturers such KS have not taken into adequate consideration when programming their larger capacity controllers degradation reductions? With the Gotways, we're not witnessing queues to A&E wards as a result of the Wheels cutting out under low battery. 

It’s interesting to see that the 100v MSX can go 4kmh faster than the 100v Monster, I always thought that the Monster went a bit faster. Of course, there’s very limited testing data (read: brave riders) to get actual top speed info from, so who knows how realistic these numbers are under real riding conditions. And, I reach the 80% beeps on the 84v MSX and Monster at the exact same speed of 51-52kmh on both wheels, despite a difference being claimed for those two wheels as well. So I’m sure the actual speed difference in the 100v wheels is smaller than what’s claimed (at least it would be for me). 

[Marty Backe]

4 hours ago, Jason McNeil said:

Update: Gotway/@Linnea Lin Gotway very kindly provided this overview of their programmed speed alerting characteristics. As @Marty Backe indicated, this 100-10% is not tilt-back, as with other manufacturers, but the level 3 audio alarms. It's interesting how Gotway permits the Rider to really push the Wheels to 80% of their max speed all the way down to where other manufacturers are limiting the cruising speed down to a snail's walking pace.  

With these 84v packs, with 6 parallels working in parallel, do you think there's an inherent (too great?) an unncessary safety margin which manufacturers such KS have not taken into adequate consideration when programming their larger capacity controllers degradation reductions? With the Gotways, we're not witnessing queues to A&E wards as a result of the Wheels cutting out under low battery. 

Very cool to see actual data direct from Gotway 

And yes, their wheel behavior is why many of us Love Gotway wheels    They allow us to fully enjoy our wheels down to 15% battery. As long as you recognize the 80-percent alarm, the wheel is not going to cut out on you.

[Jason McNeil]

23 minutes ago, Nick McCutcheon said:

interesting to see that the 100v MSX can go 4kmh faster than the 100v Monster, I always thought that the Monster went a bit faster.

I wasn't aware of this either, it just comes to show that what goes on in Engineering doesn't get disseminated to whatever marketing dept there is. 
Bear in mind that these figures are simply the 3rd level alarm, it's most certainly not a safe ride speed; there's been reported instances of Riders accelerating hard, still under the limit, with the Wheel cutting out from under them. Couldn't help myself, plotted the data into a graph.

Edited April 11, 2019 by Jason McNeil

[meepmeepmayer]

So the 80% alarm is just another fixed speed alarm in the end, albeit with speed dependent on battery voltage? That's disappointing. It doesn't take rider weight and other conditions into account and isn't an actual power draw alarm

3 hours ago, Chriull said:

Does the MSX84 allow discharge down to 3V or 3,3V per cell? I took 3,3V for now...

It's 3.3 - see here: click.

[eddiemoy]

36 minutes ago, Jason McNeil said:

I wasn't aware of this either, it just comes to show that what goes on in Engineering doesn't get disseminated to whatever marketing dept there is. 
Bear in mind that these figures are simply the 3rd level alarm, it's most certainly not a safe ride speed; there's been reported instances of Riders accelerating hard, still under the limit, with the Wheel cutting out from under them. Couldn't help myself, plotted the data into a graph.

Tesla is wrong, should the speed on the right be 40kph?

[Chriull]

1 hour ago, Jason McNeil said:

Bear in mind that these figures are simply the 3rd level alarm, it's most certainly not a safe ride speed; there's been reported instances of Riders accelerating hard, still under the limit, with the Wheel cutting out from under them.

That's the intrinsic of any fixed (or also just battery level dependend) limit/alarm - one can "outaccelerate" it. Overlean without warning is possible with every wheel - presumably needs some "overcoming" with the new powerful ones.

[myfunwheel]

Great information and input here from you guys!  Thanks for starting this topic:). Anything that can make this great hobby more enjoyable with a greater degree of safety is okay in my book.

[meepmeepmayer]

I'm coming back to this topic a lot, and just want to stress something:

• The chart with the speed reduction behavior over the battery percentage can be misleading when comparing different manufacturers, especially when considering safety at low battery.
• (But the chart is nice as a quick rider-centric overview how wheels behave because a rider goes by the battery percentage in the app.)
• Why? Because not all wheels have the same correspondence between battery % and battery voltage. But battery voltage tells how full the battery really is and what it can or cannot do, which matters for safety.
• To compare wheels, it would be better to graph the speed reductions over the battery voltage (per cell).

As an example, here's how a comparison between the 18XL and MSX would look (if someone wants to do this nicely, feel free...).

Not to scale! Just qualitative.

Please note:

• Both wheels have the same exact battery: 1600(1554) Wh which is 6x20 cells at 3500mAh. You could put a battery from the MSX into the 18XL or vice versa and not notice a difference.

What you can see:

• Gotways till now (like the MSX) consider the battery empty at 3.3V per cell. The 18XL will discharge much further to 3.0V. This is why the 18XL reportedly gets a higher range, it empties the battery further.
• (There is also an anomaly at the top end where a Gotway will consider itself at 100% battery below the maximum voltage, but that's not important here. You can charge the battery to the max voltage of 4.2V anyways, so you lose nothing, but it will not show as more than 100%.)
• The Kingsong will start speed reductions at 25% battery (3.3V). The MSX has already completely stopped at this point (low battery tiltback and all) and is at 0% battery (3.3V).
  In other words, when the KS starts any speed reductions, the MSX won't even let you ride it any longer! Same exact battery charge state! It's only interpreted differently between the wheels.
• The MSX speed reduction is actually much more conservative. You wouldn't see that if you graphed these curves over battery percentage, but you see it if you graph over battery voltage.
• The impression that the Gotway will let you run down the battery further than the Kingsong (MSX: still 45kph at 10% if we ignore the battery beeps) is wrong. Actually, it behaves in a safer way and has more backup resources as the battery empties.

(That is all. There's an aspect of Gotway-fanboyism here, but I think it's only fair to say this. A wheel that is "empty" at 3.3V per cell will in general have more conservative, presumably safer speed reductions than a wheel that is "empty" at 3V per cell.)

Edited June 13, 2019 by meepmeepmayer
image corrected

[Planemo]

This is really good info for those of us like me who really want to understand the correlation between battery voltage and wheel behaviour (tilt-back/alarms etc). As a newbie I have been really careful in bringing my speed up gradually and as a result haven't been running anywhere near the wheels capabilities yet, but as my speed is increasing with confidence I would really like to know what my wheels might do in relation to voltage.

The only thing missing is that theres no V5F or ninebot Z data! I appreciate that the wheels listed above are the most popular but if anyone has info it would be greatly received!

[AtlasP]

What I really want is a version of these charts with the "battery level [in %]" axis replaced by "distance ridden". (Edit: or at the very least as suggested by meep, scaling the chart lines by battery size.)

The problem comparing them at battery % is that they have different sized batteries. (For example, as it stands such a chart makes it look like the KS14D can go way longer/further at its max speed than the V10F which is bollocks, since the V10F has over twice the battery.) Comparing them at percentages may make sense when comparing the math of their algorithms, but it makes zero sense comparing the different wheels as products since battery percentage is an abstraction that does not directly correlate between wheels in usage.

What we really want to know is how top speed reduces per how far you go. This would also have the advantage that anyone could quickly gauge how wheels compare in range before tiltback at their personal normal cruising speed.

Edited May 27, 2019 by AtlasP

[meepmeepmayer]

Good idea. Simply scaling the chart lines by battery size sounds good.

"Distance" is not objective and highly rider- and speed-dependent, so any concrete number will inevitably disappoint some people when they can't reach it. And if you pick a default rider (80kg/180lbs?) and speed  (30kph/20mph?), it might not fit what you really do with differently sized wheels. For a 14 incher it's too fast, for an 18 incher almost too slow.

Also, distance is not proportional to battery % (the battery % which is just the voltage, which drops faster when the battery gets empty) so the lines would become actual curves.

But you have a good point for a readable chart that tells people what they can do in the real world. If it is possible to make one I think you'd have to do real world measurements for each wheel. Not sure how reliable they would be for other riders then.

[Chriull]

35 minutes ago, AtlasP said:

What I really want is a version of these charts with the "battery level [in %]" axis replace by "distance ridden

As @meepmeepmayer wrote that's a nice and important figure too. @Jason McNeil has some figures like this, too afair. But they are very dependend on riding style, inclines, speed, temperature and weight. One can use the ~12-20+ Wh/km formula to get some feeling of a possible range.

The only outlier should be the ks18(X)L which uses the battery cells down to 3V instead of just 3.3V as all/most of the other wheels. 

But this is a different topic - and has (about) nothing to do with the here shown speed reduction vs battery charhe graphs, which are of their own interest.

 

[Mike Sacristan]

@meepmeepmayer Thank you for the amazing post. It clears up a lot on the Kingsong vs MSX range question.
It also gives us better understand on the safety precautions Gotway and Kingsong have put into place.

My riding weight is around 66kg and I get 1km per % battery on my MSX 1600Wh. I ride between 25 and 35 km/h. I have been wary of riding it down to very low numbers which I see now is unnecessary as the low numbers are real numbers. And I don't have to worry about riding it down to 0 because at zero i'm still at 3.3V and not doing a deep depletion of the battery. So I quite possibly have 100km range on the MSX. 

I did some calculations and could see that ~12-20 Wh/km has been rather realistic for my riding depending on cold and more towards 14 Wh/km now that it's warmer and as long as I am not constantly pushing to 40km/h.

An interactive calculator with sliders / values and graphs would sure be something to see!

Adjustable slider for weight, speed, ambient temperature, etc. Of course we would need to show the calculations being done and what numbers we are using to "guess".

100% battery to 20% battery on my MSX.
Riding speed 25 km/h.
Riding weight 68kg.
Ambient temperature 5C
Distance achieved 70km
Wh/km 18.2

100% battery to 20% battery on my MSX.
Riding speed 25 km/h.
Riding weight 66kg.
Ambient temperature 15C
Distance achieved 90km
Wh/km 14.2

 

 

 

[US69]

On ‎5‎/‎20‎/‎2019 at 7:56 PM, meepmeepmayer said:

I'm coming back to this topic a lot, and just want to stress something:

• The chart with the speed reduction behavior over the battery percentage can be misleading when comparing different manufacturers, especially when considering safety at low battery.
• (But the chart is nice as a quick rider-centric overview how wheels behave because a rider goes by the battery percentage in the app.)
• Why? Because not all wheels have the same correspondence between battery % and battery voltage. But battery voltage tells how full the battery really is and what it can or cannot do, which matters for safety.
• To compare wheels, it would be better to graph the speed reductions over the battery voltage (per cell).

As an example, here's how a comparison between the 18XL and MSX would look (if someone wants to do this nicely, feel free...).

Please note:

• Both wheels have the same exact battery: 1600(1554) Wh which is 6x20 cells at 3500mAh. You could put a battery from the MSX into the 18XL or vice versa and not notice a difference.

What you can see:

• Gotways till now (like the MSX) consider the battery empty at 3.3V per cell. The 18XL will discharge much further to 3.0V. This is why the 18XL reportedly gets a higher range, it empties the battery further.
• (There is also an anomaly at the top end where a Gotway will consider itself at 100% battery below the maximum voltage, but that's not important here. You can charge the battery to the max voltage of 4.2V anyways, so you lose nothing, but it will not show as more than 100%.)
• The Kingsong will start speed reductions at 25% battery (3.3V). The MSX has already completely stopped at this point (low battery tiltback and all) and is at 0% battery (3.3V).
  In other words, when the KS starts any speed reductions, the MSX won't even let you ride it any longer! Same exact battery charge state! It's only interpreted differently between the wheels.
• The MSX speed reduction is actually much more conservative. You wouldn't see that if you graphed these curves over battery percentage, but you see it if you graph over battery voltage.
• The impression that the Gotway will let you run down the battery further than the Kingsong (MSX: still 45kph at 10% if we ignore the battery beeps) is wrong. Actually, it behaves in a safer way and has more backup resources as the battery empties.

(That is all. There's an aspect of Gotway-fanboyism here, but I think it's only fair to say this. A wheel that is "empty" at 3.3V per cell will in general have more conservative, presumably safer speed reductions than a wheel that is "empty" at 3V per cell.)

Actually just saw this thread and especiall your graph the first time!!!

Great done and absolutly correct!  (and what i have tried to explain in words a thousand times and no one understood my Points)

What i just wanted to add that all These curves and assumtions we see here are for the actual battery Status.

What everbody has to have in mind is that a battery is under load while driving!

Crazy accelerators can bring there 80% Full battery down to a 25% Status easily! That goes especially for "4p" batterys which drop much faster than 6p/8p or even 9p Solutions.

Edited June 13, 2019 by US69

[Mike Sacristan]

Do we know what the battery config is for the Nikola 100v 1845WH or Monster 100v 1845 for that matter?
This makes the 100v 1230 configs a bit self limiting by their own nature.

[meepmeepmayer]

20 minutes ago, US69 said:

What i just wanted to add that all These curves and assumtions we see here are for the actual battery Status.

We've already arrived at that conclusion, otherwise everything is chaos. Battery percentage is whatever the wheel shows at every moment, the end. So real life behavior can be more confusing.

4 minutes ago, Mike Sacristan said:

Do we know what the battery config is for the Nikola 100v 1845WH or Monster 100v 1845 for that matter?
This makes the 100v 1230 configs a bit self limiting by their own nature.

6x24 cells with 3450mAh. Yes the 1230Wh is 4p, not 6p. Not sure whether it's really such a limit though.

Edited June 13, 2019 by meepmeepmayer