MSX 100v VS MSX 84v

[mrelwood]

3 hours ago, Elliott Reitz said:

assumes same tiltback voltage

You may need to calculate again. 84V system has 20 cells, so voltage range of 3.0-4.2V per cell adds up to 60-84V. A 100V system with 24 cells has a range of 72–100.8V.

The low battery tilt-back is engaged when the voltage gets down to average 3.0V per cell.

If the end user calculations do not match the reported difference in behaviour, there is good reason to believe that a parameter is missing from the calculations. One aspect is that the feeling of torque does not relate directly to the maximum available torque at any moment. Acceleration by definition happens over time, and an EUC is in a constantly changing unbalanced state. The firmware behaviour can be different, which would result in a different feel. Besides, if the firmware allows for a bit of tilt, it often results in more effortless acceleration. If the 84V version hesitates a bit, it may even be a reason for better acceleration.

Edited July 26, 2019 by mrelwood

[meepmeepmayer]

7 hours ago, mrelwood said:

The low battery tilt-back is engaged when the voltage gets down to average 3.0V per cell.

Are you sure? Or is it at 3.3V per cell on the Gotways we're talking about which is "0%" battery?

Assuming 3.3V, then @Elliott Reitz's math is

(84V - 20*3.3V)/0.133 ohm = 135.3A

(100V - 24*3.3V)/0.24 ohm = 86.7A

Switches the thing around.

Why would the low battery tiltback voltage matter for torque? I'm confused

Anyways, aren't 80A or over 100A theoretical numbers meaningless because you never go there? 6p battery is 60A max continuous or maybe 120A max? (20A for a cell?) Or do crazy numbers matter as potential short peak numbers?

So looks to me like this doesn't influence torque. It's the firmware which is decisive, not the battery limit. And user reports say the 84V has more torque than the 100V, assuming torque/current and instant acceleration/oomph are the same.

[Chriull]

49 minutes ago, meepmeepmayer said:

Anyways, aren't 80A or over 100A theoretical numbers meaningless because you never go there? 6p battery is 60A max continuous or maybe 120A max? (20A for a cell?) Or do crazy numbers matter as potential short peak numbers?

Max peak current of the cells is much higher as this max continous current numbers.

But GW has some current limiting around 120A...

[mrelwood]

9 hours ago, meepmeepmayer said:

Are you sure? Or is it at 3.3V per cell on the Gotways we're talking about which is "0%" battery?

Ah, sorry. Yes, Gotway has the higher ”0%”.

 

9 hours ago, meepmeepmayer said:

Why would the low battery tiltback voltage matter for torque? I'm confused

Most people go for the easiest calculatable value when trying to compare two wheels. Explaining the behaviour properly requires further understanding of the mechanics of acceleration in general, as well as the physics of riding an EUC.

Many people compare the maximum rated motor power when comparing torque. Despite being corrected and explained that the power rating only tells us the max power that the motor can sustain for a longer perioid of time without damage, they continue to do so. ”Because it’s the only parameter available for us end users”, one person said.

 

9 hours ago, meepmeepmayer said:

6p battery is 60A max continuous or maybe 120A max? (20A for a cell?) Or do crazy numbers matter as potential short peak numbers?

Peak current can indeed be notably higher from the cells, but fast power requirements are provided mainly from the large capacitors. That’s why the pedals ”go soft” if a capacitor foes out or breaks a leg.

 

9 hours ago, meepmeepmayer said:

So looks to me like this doesn't influence torque. It's the firmware which is decisive, not the battery limit.

I agree completely.

 

[meepmeepmayer]

@mrelwood Thanks.

Still not sure why a voltage difference would be taken into account.

Smallest voltage (66V)/resistance (of 20s or 24s) = max current (possibly ignoring what the batteries can actually do, which might be less). But what's the point of using a voltage delta? Just to compare some motor specs without meaning to the number itself?

I'm missing something here. @Elliott Reitz can you explain to us why you did this computation like you did? Always happy to get some knowledge from someone who actually knows something (for real!) in this vague EUC world

[Elliott Reitz]

I like the replies!  You'all've mentioned things I had not considered.   Specific answers where I have them:

mrelwood:  good points... we don't yet know about how the thresholdS are set in software.  That same software (weather same, different, or even adaptive) between configurationscan also affect the answer we all seek with open-source certainty (which is why I post my math rather than just my momentary opinions (disclaimer:  I'm awaiting a 100V wheel so my emotions are high right now).

meepmeepmayor:  " And user reports say the 84V has more torque than the 100V"... NFW, BS, GTFO!  I've not heard any credible side-by-side reports.  If you have than reference it.  Otherwise, others have emotions like I do, favored outcomes and have posted them speculatively... I hope you can discern the subtle difference here between speculation with week fact-sets vs TESTED TRUTH!  We here per this thread ALL want that ultimate answer.  The only thing that would be near as good would be a Gotway engineer's answer (with explination and answers to the prior-posts here... and w/o such nor test would be yet another speculator like us).

chriull:  yes, as you say... doesn't change our speculations that I can figure yet.

mrelwood:  Yes, firmware rules.  As we all stared out here with our personal assumptions we've discussed our way through how yet another unknown could change the answer.

meepmeepmayor:  I had first calculated currents vs battery resistance to reveal the config with max-torque... modified to find the "crossover" in battery configuration capabilities... then modified to entertain 72V threshold... then included in same post the possibility of firmware difference (or simple firmware adaptation, and NOTE the 4 vs 5 wire charging adapter means there's definitely that hardware difference which means software can know about it).  So the result is I've only demonstrated the ohm's law approach to the answer based on whatever assumptions we can find {edit+:  more like speculate analyze and confirm or not}. 

So for now, we still lack the needed details about the configuration differences and do not yet (that I've seen link to) a definitive test/demo or GW answer about assumptions.

PS:   I get my new MSX 100V on TUESDAY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  {edit add:  which is why I found this forum, joined, read the first several pages before selecting the 100V and initiating my purchase. I still don't know if that was the best value selection at $1900 incl.tax but the schedule urgency with performance speculation led to my purchase selection choice.}

Edited July 28, 2019 by Elliott Reitz
clarify

[mrelwood]

 

3 hours ago, Elliott Reitz said:

meepmeepmayor:  " And user reports say the 84V has more torque than the 100V"... NFW, BS, GTFO!  I've not heard any credible side-by-side reports.

Nor will you, is my guess. IIRC, whenever the 100V and 84V were compared in a group ride, there were some riders that didn’t feel any difference. It is even possible that the ones that did feel a difference, only expected to feel something more from the 100V, and when they didn’t, they experienced the torque as being smaller. Even if it were exactly the same.

 

3 hours ago, Elliott Reitz said:

The only thing that would be near as good would be a Gotway engineer's answer

I am certain that the users of this forum have vastly more information, knowledge and skill on any subject than any Gotway employee... I would take anything coming from the horse’s mouth with a huge grain of salt.

 

3 hours ago, Elliott Reitz said:

PS:   I get my new MSX 100V on TUESDAY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Congrats! I hope it will serve you well. At least it is known to be the second fastest EUC model ever made!

[Elliott Reitz]

So what is now the fastest EUC model ever made?  To my knowledge it was the 100V MSX (faster than monster). 

 

Edited July 28, 2019 by Elliott Reitz
Fix attached image

[meepmeepmayer]

100V MSX unless the 100V Nikola somehow beats it. Which is unlikely, given that the motor is probably the same.

[mrelwood]

100V Monster is slower than the 100V MSX!? Where’s the point and sense in that?!

[Elliott Reitz]

So my 100V MSX got here today and I now have 7 miles on it.  It beeps at 30 kmh (18 mph).  IDK if there is some way to set that higher?  In the app Alarm setting it says first class and second class alarms have been turned off. 

{add via edit:}

I solved the 30 kph beep... even though the app said the alarms were turned off I tapped that in the app like I was going to turn them on. The app status didn't change, but the wheel did. Using 2 hands I can lift the wheel and control its speed. Before app changing I confirmed the 30 kph. After app changing it now starts beeping at 70 kph and free spins up to 95 kph where it cuts out (stops very quickly too with force then goes limp).

Edited July 30, 2019 by Elliott Reitz
append solution

[Mono]

On 7/29/2019 at 1:06 AM, mrelwood said:

100V Monster is slower than the 100V MSX!? Where’s the point and sense in that?!

Size speed is not everything 

[mrelwood]

1 hour ago, Mono said:

Size speed is not everything 

Absolutely agree. But if one is purchasing any 100V wheel, it must be at the very top.

If the tire of the 100V Monster would spin at the same RPM as on the 100V MSX, it would go nearly 90km/h. But it only goes 65km/h. If I’d bought a 100V Monster, I’d be complaning that it takes me 36% longer to go to places! Since I rode about 6000km in the last year, it equals a full 24 hour day in lost time! With my current salary it would... nevermind.

(What ”avg speed”?! I don’t do ”avg speed”!!)

[Mono]

1 hour ago, mrelwood said:

But if one is purchasing any 100V wheel, it must be at the very top.

I suspect a voltage step up even from 50V to 100V to be in the context of an electric motor with a few kW power technologically irrelevant. Voltage in itself is not a performance determining factor. I always expected that the 100V number is used as a selling point but not for selling superior technology. That's what I still expect. 

Edited July 31, 2019 by Mono

[Elliott Reitz]

On 7/30/2019 at 6:51 PM, mrelwood said:

Absolutely agree. But if one is purchasing any 100V wheel, it must be at the very top.

If the tire of the 100V Monster would spin at the same RPM as on the 100V MSX, it would go nearly 90km/h. But it only goes 65km/h. If I’d bought a 100V Monster, I’d be complaning that it takes me 36% longer to go to places! Since I rode about 6000km in the last year, it equals a full 24 hour day in lost time! With my current salary it would... nevermind.

(What ”avg speed”?! I don’t do ”avg speed”!!)

With over 100 miles my 1-week-new MSX 100V, the wheel is faster than me (33 mph max ride speed so-far) and has more range than me (7x 20 mile rides so far, today 30 with 64% remaining------------------------   hhhhhhhhhhmmmmmmmmmmmmmmmmmmmm... regeneration had to contribute... I was on Syracuse University hill... up/down, fast/fun too).

Oh and when I got home Wheel App said my ”avg speed” was 16 mph. The fastest I watched myself via the app display was only 25.  In traffic I do think I exceeded 30...

So which margin is more important to me now? 

- Max speed?

- Max range?

...............  my choice buying the MSX 100V was "speed margin" rationalized as a safety concept. 

............... as of now?  Well my e+ is getting very old and beat up (wanna try it for a ride... 50+ people tried, 5 did it)  and I really like 16" for the sidewalk/grass and suburban-street runs with my dog.  Cooch_Tech's review of the 14" MCM5 is appealing though the 16" e+ seems small enough to maneuver through crowds of people and has 20 mile range (though my speeds on average <10 (2 hours+)).   So 14"?  I'm concerned about its bumpiness and vulnerability to grassy terrain. 

So I've learned to love my Gotway...

Pondering the Nikola (17") vs Tesla (16") next.  So far leaning toward TESLA for my dog (well time running him is like time with God... and the MSX is faster/bigger than him and so smaller but not too small).  Chooch_Teck?  Marty?  16" seems small'ish to me... And as for the Nikola that could be like trying to replace the wrong wheel since its more an over 20mph and bigger... What's the best "doG wheeL"?

On 7/30/2019 at 7:56 PM, Mono said:

I suspect a voltage step up even from 50V to 100V to be in the context of an electric motor with a few kW power technologically irrelevant. Voltage in itself is not a performance determining factor. I always expected that the 100V number is used as a selling point but not for selling superior technology. That's what I still expect. 

IMHO, looking back I'm thinking here with THIS POST that I'm adding and selecting a key selection concept... it was subconscious when selecting my 1st wheel.  But now, after getting the "best performance wheel" (power to weight ratio, wheel diameter for desired "rail road tracks ride" type terrain), I was right to do so.  Why?

Well higher voltage does get more power through the same motors.  That's especially true for short blasts.  That's where I associate the concept with safety.

Like going down a street and spotting a rough area... I like "soft mode" but I want to know that what my brain selects "GETS DONE" by the wheel.  For that I've not yet seen anyone post anything better than the 100V MSX. 

PS:  I've only spent a few hours on the MSX getting over 100 miles... on the e+ I'm approaching 130 hours for 600 miles.  YOUR TIME RIDING MATTERS!  What else do I think matters for NUBIES?   Well now that I have 2 wheels, I gotta say the MSX "doubled" the skills, and on the e+ I have skills I've yet to accomplish on the MSX. 

PPS:  These wheels both give me... 

Edited August 15, 2019 by Elliott Reitz

[mrelwood]

7 hours ago, Elliott Reitz said:

Cooch_Tech's review of the 14" MCM5 is appealing

Yeah, well... which review of his isn’t?  I dislike 14” wheels with a passion, even when I haven’t tried the MCM5. I’m a tall guy and I weigh about 205lbs, and I’m certain that no wheel with a 14x2.125” tire can give me what I want from an EUC. 

7 hours ago, Elliott Reitz said:

What's the best "doG wheeL"?

I guess it depends what kind of dogging one does. For myself I’d go for one that allows for the easiest crawl speeds, which calls for a wide tire. Z10 even, or either of the new 16x3.0” ones. All three have practically the same tire diameter.

7 hours ago, Elliott Reitz said:

Well higher voltage does get more power through the same motors.

I’m not convinced it’s that simple. When comparing 84V wheels and their 100V revisions, Marty was the first one that could say that the difference was noticeably in the 100V’s favor. I’m certain that Marty feels the wheels with an exceptional precision, and can feel minute details in wheel behaviour that most others would not. If it requires for him to do a controlled and repeated blind test to be able to say that there is a ”noticeable” difference, I’m sure the difference is a very small one.

When it comes to the safety buffer, I look at it like this: The 84V MSX is already a top performer in power and speed. And there are videos from people overleaning the 100V as well. The difference in their ability to accelerate before overlean has been pondered quite a bit, without getting even a clear consensus on which one is indeed better in that regard.

Every single piece of information I’ve been able to gather on the subject tells me that if there is a difference, the difference must be very small. The price difference isn’t though. If one has the funds and feels that the extra cost is justified, then he should buy the 100V version. But if someone asks which one he should buy... That is a tough advice to make, based on what we know so far.

[Elliott Reitz]

On 8/15/2019 at 8:25 AM, mrelwood said:

Yeah, well... which review of his isn’t?  I dislike 14” wheels with a passion, even when I haven’t tried the MCM5. I’m a tall guy and I weigh about 205lbs, and I’m certain that no wheel with a 14x2.125” tire can give me what I want from an EUC. 

I guess it depends what kind of dogging one does. For myself I’d go for one that allows for the easiest crawl speeds, which calls for a wide tire. Z10 even, or either of the new 16x3.0” ones. All three have practically the same tire diameter.

I think my e+ will make it to winter without having to add the washers to remove scraping.  I only get scrapes with a carve-move.  As for your dislike of 14" wheels I'm likely to feel the same if I tried one.  The 16" e+ is just big enough to ride over grass and gravel without worry.  As for 14"... IDK.  As for ultra-slow manourvability I'm not so sure the tire-thickness is such a key since the e+ does quite well with maneuverability (and I carve more than twist).  And I'm not in the mind of replacing the fast ride MSX.  So maybe this spring I will be looking for something like a 16" Tesla rather than 17" Nikola.

On 8/15/2019 at 8:25 AM, mrelwood said:

I’m not convinced it’s that simple. When comparing 84V wheels and their 100V revisions, Marty was the first one that could say that the difference was noticeably in the 100V’s favor. I’m certain that Marty feels the wheels with an exceptional precision, and can feel minute details in wheel behaviour that most others would not. If it requires for him to do a controlled and repeated blind test to be able to say that there is a ”noticeable” difference, I’m sure the difference is a very small one.

When it comes to the safety buffer, I look at it like this: The 84V MSX is already a top performer in power and speed. And there are videos from people overleaning the 100V as well. The difference in their ability to accelerate before overlean has been pondered quite a bit, without getting even a clear consensus on which one is indeed better in that regard.

Every single piece of information I’ve been able to gather on the subject tells me that if there is a difference, the difference must be very small. The price difference isn’t though. If one has the funds and feels that the extra cost is justified, then he should buy the 100V version. But if someone asks which one he should buy... That is a tough advice to make, based on what we know so far.

Torque margin, max-lean, acceleration:   I concur the 84V vs 100V 1350Wh are debatable and if the 84V may have a lowest speed higher torque it would be overcome by the 100V above about 6 mph or 10 kph.  That said, note the MSX+ (or battery mod) for the 1600Wh 100V MSX will surely be the torqui'est of the MSXs (for now anyway... batteries are always getting better).

Top speed margin: I know my last alarm is 45 mph on the 100V with 10 mph speed margin. I can 2-hand-lift my 100V MSX and run it up to 58 mph and back down 0 mph without it sutting off.    I've now had my MSX 100V above 30 mph several times.  I think the highest speed I've gone is around 35 (without alarms).  Since I have motorcycle gear and experience I can help describe the experience at 35 mph and what going faster demands. 

Going above the 84V last alarm speed Vs Going between 35 and 45 on the 100V MSX:

With wind at your back and a forward lean at the waste, you can use your arms like wings but definitely not 1 arm like a turn signal.  To sustain speed over 25 you'll want eye and hearing protection (full face or goggles/earplugs). 

 

 

Edited August 17, 2019 by Elliott Reitz
minor corrections

[Gazza-usa]

On 9/27/2018 at 10:24 AM, EUC GUY said:

From what i saw, the pcb and components dont give out. only concern is heat. and not heat from the mosfets, but the cables.  I will make an alarm myself that triggers before the insulation melts, but i also talked to Lukas about adding this as a feature going forward. he said he would take it further. i hope he does. With this added, you could not kill this wheel

My thoughts.  Power into the wheel is what the driving force is.  The stator has a finite resistance (impedance + resistance).  Power is related to the frequency of switching (LI^2 * duty cycle(ish) + V^2/R losses).  So assuming the magnetics are efficient to 100% the main losses are in the V^2/R.  You raise the voltage you significantly improve efficiency.  This is why Power distribution is at high voltage.  Resistive losses.

Edited August 31, 2019 by Gazza-usa

[Elliott Reitz]

On 7/19/2019 at 1:00 PM, Elliott Reitz said:

Additionally, I found the internal resistance of the battery cells is 0.04 ohms.  Link: https://www.hurt.com.pl/prods/bat/_li_ion/ncr18650ga.pdf

So, assuming 24 cells in series for 100V, the internal resistance of the 100V series is 0.96 ohms. This means a 10A strand drops nearly 10V at that surge of current.  It also means 15A will drop 14.4V. 

So going back to the 4x24 vs 6x 20 cells wiring, the 100V system would already be running 60A to get to 85V... and by the time the 84V were drawing 60 amps it would be dropping 8 volts (100 V still has more power at 84V system).    Both systems have a theoretical 100A maximum battery limit through series resistance. 

100V has more power and more torque.

QED

Observed on my 100V MSX today using Wheel Log (no warning beeps):

1. Decelerate 84 A peak 30 mph to 5 mph (overcharge current (shunted through BMS?)).  I don't remember any severe stops... just that I did the stop/start for red lights and stop signs.
2. Accel avg 60A peak 5 to 25 mph. These were strong enough for traffic, not max possible lean in.  Done several times.
3. Cruise avg 25 mph 30 A (riding at about 220 lbs including the guitar/pack).
4. {+} 65 A peak going up a steep hill at 5 mph (with a strong lean-in-acceleration). 
5. {+} 75 A peak doing a free-wheel demo at 45 mph (alarm but no cutoff)

Edited September 6, 2019 by Elliott Reitz
{+}