Top speed of 84v Monster V2

[Chriull]

33 minutes ago, Slartibartfast said:

I would say everything happened between points 16 and 17, when the speed was at 52 km/h and the "phase_current" plummets from 65 to -10 for no apparent reason.

My guess would be that the current dropped because you already lost contact to the wheel and it had no burden anymore. Maybe it was already tilted too far so the firmware stopped powering the motor?

40 minutes ago, Slartibartfast said:

Who knows if the wheel basically just shut off, making me fall, or if I fell which lead to the wheel shutting off: ¯\_(ツ)_/¯

But yes, very hard to get something from this.

Chances imho seem good that it was no malfunction causing the wheel to shut off.

Most important that you got through this accident more or less good, i hope!?

[Slartibartfast]

Yeah, I'm pretty much good.

Spent most the afternoon in emergency as I have pretty bad grazing but it's only surface abrasions. Very painful but no significant damage, thank goodness.

Doc recons I should heal in a week or so and shouldn't have any long term issues. Right now though, I sure am pretty sore (and not to mention stinky)!

Edited January 24, 2022 by Slartibartfast

[Mike Sacristan]

I was out for a ride on my amazingly fast MSX 84 yesterday. 

I beeped at 48.3kmh and at that moment I was riding a slight incline, -1C, 72 kg riding weight. I stopped and checked my battery and I was at 58% or 75.9V. I looked at the log and the lowest voltage was 72v when the alarm triggered. So there was some voltage sag.

According to the speed reduction thread the MSX has a top speed of 58kmh and full battery. However this is only for the very top and the next step down is 55kmh. Even using 55kmh for Darknessbot smart alarms will set Darknessbot off later after the beeps. 53kmh is spot on. The speed reduction for Gotway wheels is 20%. So I would say the MSX and Monster V1 & 2 are similar when it comes to beeps.

If we just go linear all the way down to 0% starting at 53kmh then we get the following 80% alarms:

100% battery = 53kmh
50% battery = 47.7kmh
0% battery = 42.5kmh

So the lowest value is the top speed reduced by 20%. However the value stops decreasing at 30% (for 84v wheels). The lowest 5 beep speed is 45kmh.

So if I beep at 47.7kmh and 50% battery... at what speed will I over lean the wheel?
You can push from 80% to ~90% power and achieve ~52kmh and then somewhere above that expect to over lean or cut off as many like to say.

I made this chart a while back. The values are calculated as following:

5 beep speed * 1.1 = Max safe kmh
5 beep speed * 1.2 = Cut off kmh

MSX 84V
Battery	5 beeps kmh	5 beeps mph	Cut off kmh	Cut off mph	Max safe kmh	Max safe mph
100%	53	32,9	63,6	39,5	58,3	36,22
90%	51,94	32,2	62,328	38,7	57,134	35,5
80%	50,88	31,6	61,056	37,9	55,968	34,7
70%	49,82	30,9	59,784	37,1	54,802	34
60%	48,76	30,2	58,512	36,3	53,636	33,3
50%	47,7	29,6	57,24	35,5	52,47	32,6
40%	46,64	28,9	55,968	34,7	51,304	31,8
30%	45,58	28,3	54,696	33,9	50,138	31,1
20%	44,52	27,6	53,424	33,1	48,972	30,4
10%	43,46	27	52,152	32,4	47,806	29,7
0%	42,5908	26,4	51,10896	31,7	46,84988	29,1

 

 

 

[Slartibartfast]

Very interesting.

When you say battery% are you referring to the "at rest" value or the "under load" value. At the time my battery would have been at about 85% charge but under the given load it would have reported something more like 50%.

It seems you're referring to the at rest level though. So according to this table I should have heard beeps at 50, been at "Max safe" at 56 and cut off at 61. Obviously this is just a theoretical guide, and admittedly I'm heavier than most, but a cutoff at 56 km/h is at least somewhat unexpected.

Edited January 24, 2022 by Slartibartfast

[Mike Sacristan]

5 minutes ago, Slartibartfast said:

Very interesting.

When you say battery% are you referring to the "at rest" value or the "under load" value. At the time my battery would have been at about 85% charge but under the given load it would have reported something more like 50%.

That's an interesting question and I have found the answer to be somewhere in between those two values.
I try to see the EUC as a taser. If I am tasing someone at 100v and the battery voltage drops to 95v am I still tasing them at 100v or am I tasing them at 95v? 

Your battery was at 85%.
We assume 100% to be 84v and 55kmh and we assume 0% to be 66v and 45kmh.
So we get 84v-66v which is 18v and thus our 100% voltage value.
We get 55kmh - 45kmh which is 10kmh and that is our 100% of available speed at 5 beeps.
We calculate 85% of 18v. We add that to 66v and end up with 81.3v.
We calculate 85% of 10kmh. We add that to 45kmh and end up with 53.5kmh 5 beeps at 81.3v.
We calculate *1.1 for the max safe speed and end up at 58.85kmh or around 90% load but probably a bit higher due to wind resistance.

If we base it all off of 50% then you would have beeped at 50kmh / 79v with 90% being at 55kmh.

So somewhere in between. Which is not a lot! Since the lowest and highest speeds are 45kmh/55kmh. Every 10% of voltage reduction lowers the top speed by 1kmh.

Much like doing the dishes. If you have done half the dishes and half is remaining. That remaining half is 100% of the dishes that needs to be done. Or in my case, two plates and coffee cup.

I have tested with quite a few wheels. Some riders in the group have even tested the max safe for me and I was able to verify cut out speeds too. 

Here I am on the MSP. The MSP calculations are based off 100% being 58kmh (the wheel over reports speed as shown by the GPS).
I hit wheel reported 64kmh and at that exact time the app reported 85% battery.
I am within limits though and my numbers are conservative since I use *1.1 and not *1.125 and *1.2 and not *1.25.

 

 

[supercurio]

5 hours ago, Slartibartfast said:

Who knows if the wheel basically just shut off, making me fall, or if I fell which lead to the wheel shutting off: ¯\_(ツ)_/¯

I know! 👋

From looking at all your detailed data (thanks for sharing again)

• speed increasing
• constant high torque
• voltage falling down

There's exactly 0 doubt that it's a rider triggered overlean condition, which made you fall, and the wheel stopped producing torque because it fell and had no rider (but did not shut off, you would not have data point)

On wheels reporting accelerometer data like Inmotion or Sherman, forward tilt would be a good addition in the graphs as well to follow the overlean itself.

I wish you to heal well 🙏, although I have to admit I don't understand how your main conclusion is not to make the beeper work before ever riding this wheel.
And I am genuinely concern that you'll crash again the same way another time, which is a likely possibility if pursuing having speed-based alarms as only means of safety.

Edited January 24, 2022 by supercurio

[Slartibartfast]

9 hours ago, supercurio said:

There's exactly 0 doubt that it's a rider triggered overlean condition

Fair enough. What would the data look like if the wheel did cut-out?

 

9 hours ago, supercurio said:

I don't understand how your main conclusion is not to make the beeper work before ever riding this wheel

Fair point, and I will try to get the beeper working again.

My main conclusion though is to simply not ride it so fast! I knew exactly how fast I was going and thought it was well within the range of the wheel. Now that I know it isn't I simply won't ride it that fast again.

I will also ensure the tiltback is enabled again (which I thought it was at the time) and set it to something around 40 km/h. I wish there was something like an 80% option for tiltback (which is actually how I thought it worked) but alas it seems there isn't.

I will also endeavour to get this buzzer working again but I actually have the least faith in this mechanism overall, simply because I just can't hear it at speed.

 

In all honesty though, the main thing that is going to keep me safe on this wheel is simply having the knowledge that it cuts out (or overleans) at 55 km/h! Yes, yes I know that I can't always rely upon 55 being the cutout but simply being aware that it's around there will make my riding so much safer. As I say, I seriously thought this wheel was capable of speeds much higher that it is and honestly believed 55 was well within its range when it simply just isn't! Basically just knowing that alone will make a HUGE difference.

Edited January 24, 2022 by Slartibartfast

[supercurio]

21 minutes ago, Slartibartfast said:

Fair enough. What would the data look like if the wheel did cut-out?

It would look like nothing special happening, and it cut-out for no apparent reason.

Like at the moment the V12 which can die on a small bump or jump (and the wheel shuts off instantly, not transmitting the data)

21 minutes ago, Slartibartfast said:

Fair point, and I will try to get the beeper working again.

My main conclusion though is to simply not ride it so fast! I knew exactly how fast I was going and thought it was well within the range of the wheel. Now that I know it isn't I simply won't ride it that fast again.

Ah yes, it is hard to never get carried away and have a fair appreciation of speed subjectively.
One example: strong tailwind. Feels like you're almost not moving at all (no resistance, no wind noise), yet you might be moving near max speed. A very strange sensation when that happens!

Hopefully this beeper works. You can test my app during a free-spin also, see if it beeps.

21 minutes ago, Slartibartfast said:

I will also ensure the tiltback is enabled again (which I thought it was at the time) and set it to something around 40 km/h. I wish there was something like an 80% option for tiltback (which is actually how I thought it worked) but alas it seems there isn't.

Ah yeah let us know how is the tiltback experience on this wheel. If you can tell that it's happening or if it's creeping in slowly and hard to actually notice?

21 minutes ago, Slartibartfast said:

I will also endeavour to get this buzzer working again but I actually have the least faith in this mechanism overall, simply because I just can't hear it at speed.

Yes that's a problem with many older wheels especially, for some it's nearly impossible to hear the beeps.

I personally always ride with earmuffs (originally to keep ears warm during winter) which reduce wind noise by something like -20 to -30 dB. So you can hear beeps then - if the ambient and tire noise is not too loud.

21 minutes ago, Slartibartfast said:

In all honesty though, the main thing that is going to keep me safe on this wheel is simply having the knowledge that it cuts out (or overleans) at 55 km/h!

Probably not at lower battery state of charge with voltage sag, right? 😋