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travsformation

18XL: NO low-battery speed THROTTLING?

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Hi, 

I'm wondering what other 18XL owners' experience is with the 18XL in terms of speed throttling at low battery. My experience is... It's never done it to me... Ever. Granted, I usually charge it when it gets down to 30% (I like long rides so I tend to want to make sure I'll have plenty of range whenever I go out for a ride), but the when times I've gone below 25%...no speed throttling if any kind. 

The day before yesterday I got it down to 15% (idle) by the end of the ride, and zero tiltback our speed throttling. Even during the last few kms, (I was monitoring Wheelog constantly while riding), the battery ranged from 5-8% under stress, and dropped to 0% on a few steepish climbs, still no throttling.

Is this normal? Should I be worried? 

Granted, on such low battery I throttle myself out of common sense (no high speed, yet to avoid bumps, etc), but I'd still like to know whether this is an isolated issue with my wheel or if others area experiencing the same thing. Thanks! 

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Just infected by gotway virus. :efee612b4b:

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Maybe it’s not a strict percentage but some voltage trigger. If you’re light weight and don’t do sudden pushes for acceleration it might not go under certain voltage and trigger throttling. And did you really try going 50 km/h? Maybe it throttles only slightly. 

I’ve also never seen throttling as my longest rides have been about 60 km. I still had 52% battery left at that point. 

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The percentage is the voltage.

The speed limit throttling down from 50kph starts at 25% battery and goes to 12kph at 0%. Maybe you were simply too slow to encounter it? Even 5% battery is nearly 20kph.

uc?export=view&id=14-HRSVVsorJ7KZRyK0SeB

(Picture from here)

You can always take your wheel at low battery, lift it, and carefully and slowly spin it up to see if any beeps/tiltback (you feel it as a jolt and then the wheel spins up rapidly) appear (and at what speed). Just to be sure the warnings are there.

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Wheellog doesn't have an 18(X)L option yet? @Seba:efef62fc70: (It also needs a 16X option for 3.15V empty voltage along with the option for the 18(X)L with 3V empty voltage.)

In that case, "0%" is actually 25% so naturally there's no throttling because that only starts at 25%.

Edited by meepmeepmayer

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15 minutes ago, meepmeepmayer said:

It also needs a 16X option for 3.15V empty voltage along with the option for the 18(X)L with 3V empty voltage.

The 16X doesn't go down to 3 V... Do we know why it is different?

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10 minutes ago, The Fat Unicyclist said:

Do we know why it is different?

No. All I know is that @US69 has confirmed 3V for the 18(X)L and 3.15V for the 16X.

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37 minutes ago, meepmeepmayer said:

Wheellog doesn't have an 18(X)L option yet? @Seba:efef62fc70: (It also needs a 16X option for 3.15V empty voltage along with the option for the 18(X)L with 3V empty voltage.)

In that case, "0%" is actually 25% so naturally there's no throttling because that only starts at 25%.

 

44 minutes ago, The Fat Unicyclist said:

I read somewhere (here on the forum) the the 18XL drains the batteries to a lower level than other wheels (which is a part of the reason the range is so good).

The problem is WheelLog doesn't allow for that, so when it reports 0% the wheel is actually has a reasonable amount left - If you recall the range test that @Marty Backe did, he got home with WheelLog showing empty, but still had 2-3 lights on the wheel.

I have ridden my 18XL down to 5% (as reported by the KS App, not WheelLog) and I can tell you there is definitely a tiltback!

WheelLog also doesn't report an accurate battery level for the Nikola. I have stopped using the Seba version and reverted back to the older WheelLog.

I do need to repeat my XL range test, but this time ride until tilt-back kicks me off the wheel.

Edited by Marty Backe

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41 minutes ago, buell47 said:

If the battery percentage is wrong, just use the the displayed voltage in the app?

Gotway 84V = 20 x 3.0 Volt = 60V empty 

KS16X = 20 x 3.15 = 63V empty 

KS18XL = 20 x 3.3 = 66V empty

:)

Yes, this works. (But did you mix Gotway and 18XL numbers?)

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1 hour ago, UniVehje said:

Yes, this works. (But did you mix Gotway and 18XL numbers?)

Yes, I corrected it. :whistling:

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I can never keep the ks app on for an entire ride....it always disconnects or something while my phone is in my pocket...I then have to shut the wheel down inorder to reconnect to app!

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Use the Wheellog App instead. 

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According to Jon, on his 1000km SpeedyFeet review of the 18XL, there was a firmware issue at some point that would cause the low battery alarm not to sound.  Watch the very end of the review where he updates the firmware.  He could not swear that was the issue, but it sure seemed like it.  So you might want to check if you're up-to-date with your firmware.

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On 8/4/2019 at 8:09 PM, FreeRide said:

According to Jon, on his 1000km SpeedyFeet review of the 18XL, there was a firmware issue at some point that would cause the low battery alarm not to sound.  Watch the very end of the review where he updates the firmware.  He could not swear that was the issue, but it sure seemed like it.  So you might want to check if you're up-to-date with your firmware.

Nothing against Speedyfeet and companion...

But they are very good at ignoring my advices, that there is a VOICE on or off method. 

So with voice ON you will not get any beeps...just the very late „your device is low battery“...

So perhaps that moght also have been a reason.

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Thanks @meepmeepmayer and @The Fat Unicyclist for the info (and sorry for taking so long to reply). Based on the chart you posted, meep, at sub-20% battery (according to Seba's fork of WheelLog, which it would appear, isn't an accurate value), I was riding at <30 km/h, just to be on the safe side, so I'm not surprised I didn't get any titlback: real battery value was probably more like 35%, so at 30 km/h, I would have had to drain the battery down to approx. 12% (real percentage) before experiencing any tiltback. Will have to keep testing (although I'd rather not drain the battery that far down in the first place)

Overall, Am very pleased with the lack of speed throttling with the 18XL, but can't help but wonder how safe these margins are. Has this been discussed elsewhere?

Am also very happy with the range I'm getting from this wheel. On average, I get 70q-75 km per charge..so it's nice to know I have another 25% to squeeze out of it, should the need ever arise :)
 

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On 8/3/2019 at 7:39 PM, meepmeepmayer said:

World of Electric Unicycles (Seba Wheellog) uses a different algorithm to compute the battery % (so it behaves like an actual battery percentage would). Both you and I don't like that.

My WheelLog version and the one from Google Play both use exactly the same algorithm for calculating the battery level :) I haven't changed anything and as far as I know, nothing has changed in the Google Play version code either. Because the code for both WheelLog versions is in GitHub repos (Google Play at https://github.com/palachzzz/WheelLogAndroid and mine at https://github.com/slastowski/WheelLogAndroid), this can be easily checked (battery level calculation routines are in WheelData.java). Of course, some old versions of WheelLog may use a different algorithm, but both current WheelLog from Google Play and the one from euc.world work identically in this respect.

 

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2 minutes ago, Seba said:

Today I received KS-16X from Polish distributor for testing, so I will create voltage-to-level map according to original KS app. I will also try to map speed limit-to-voltage.

Thanks for all your work, Seba! :D

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On 9/18/2019 at 9:49 AM, Seba said:

By the way, all this discussion about battery levels is purely academic, theoretical :) In practice, voltage below 3.3 V at no load should be considered a fully discharged battery. Why? Just look at the battery discharge curve - roughly just to 3.3 V, the voltage linearly corresponds to the capacity. Further discharge causes a sharp drop in voltage, and the difference between 3.0 V and 3.15 V is insignificant from the point of view of the remaining battery capacity. In addition, we are talking here about the operating conditions of the battery without load. For example, at a standstill, the KS-16X battery has a voltage of 82.5 V. Then we start riding. At 10 A of power consumption (80 kg rider going up the 7% hill with 25 kph), the voltage drops by 0.5 V.

https://batteryuniversity.com/learn/article/discharge_characteristics_li

Interesting, thanks for sharing. Does that mean no voltage-to-level mapping according to the original KS app though?

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OK, so today I got my first battery/speed tiltback....talk about a brown pants moment! It's the first I've had tiltback on the 18XL while going at speed....Now I finally know what people have been talking about: MAN is that harsh! Almost fell off the wheel! :efee612b4b:

Curious about why it had happened, since WheelLog had last reported 37% battery, I stopped to check. It's worth noting that WheelLog (euc.world) now has an option for realistic battery level (which is the Seba-algorithm® that it's been using until now); if that option is unchecked, it reports values much closer to the wheel's LED indicator (and presumably, the KS app, but I haven't verified that). I'd unchecked it—to try it out, and because I assumed it was unlikely that the wheel was reporting an incorrect battery level. 

And here's where it gets interesting: I got the tiltback going somewhere in the vicinity of 30-35 kph. When I stopped, WheelLog reported 35% battery, which is extremely close to the wheel's 3 LEDs out of 9, which should be in the vicinity of 33%. At that battery level, I shouldn't be getting any throttling, even at 50 kph. So I checked the realistic battery option in WheelLog: 13%.  

When I got home, I checked the speed throttling graph:

uc?export=view&id=14-HRSVVsorJ7KZRyK0SeB

Sure enough, the realistic option in euc.world WheelLog coincides with the speed I got the tiltback at, so it would appear that @Seba's algorithm is actually the most accurate. 

What has me puzzled is that in terms of speed throttling,  Seba's algorithm matches the graph perfectly, while the battery reported by the wheel doesn't. Which has me wondering...which app was used when making this graph? Now I wish I'd been able to check the KS app to see what battery % it was reporting, but I don't have that piece of [text missing] on my phone :efee612b4b:

I tried to test again, and when I reached 30+ kph, the wheel emitted a single beep and I chickened out before the wheel tried to throw me off (it wasn't the time or the place to risk a faceplant + runaway wheel; Saturday afternoon, busy-ish street...). Now I'm curious as to whether all of the above is a load of crap and I simply accelerated too aggressively (although I've never had overlean tiltback with the 18XL before, and I wasn't riding all that aggressively...). Hmmm....I loves me a good mystery :efee612b4b: 

I wish I hadn't plugged the wheel in when I got home...now I'm going to have to live with the nagging doubt until my wheel gets down to a similar battery level again :roflmao:

Edit: I just recalled that all 3 LEDs were yellow; maybe the 3rd LED was about to go out, so battery could have been anywhere between 22% and 33%...All the same, even at 22%, it shouldn't have throttled until a little below 45 kph...Hmmm....the plot thickens :roflmao:

 

 

Edited by travsformation

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