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winterwheel

Time for some super cold commuting

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But as a California resident, I’m probably paranoid that these temperatures may affect the wheels ability to function. Can someone verify if a cutout would or wouldn’t be a risk? It’s outside of the manufacturers temp ranges for a reason right?

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Now we need covers for our wheels just to keep them warm enough to function! Maybe if he doesn't leave the wheel outside it will generate enough heat so that the operating components stay within range? I dunno its interesting. I know cars up north have engine block heaters but us down here Texas don't really know what thats like. ;)

Edited by scap

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Block heater equivalent function for the wheel would be an awesome idea!

I *never* leave the wheel outside in cold temps, it is only out there when I am riding it.

The ACM2 generates enough heat when carrying me (at 240+lbs riding weight) to offset ambient temps down to -20C. Below that it starts to cool down during the ride, kind of the opposite of what happens on Overheat Hill I suppose.

It'll be interesting to see how the XL compares.

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When you were looking for a commuting vehicle to cope in -30 temperatures, what was it about the electric unicycle that attracted you?

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4 hours ago, mike_bike_kite said:

When you were looking for a commuting vehicle to cope in -30 temperatures, what was it about the electric unicycle that attracted you?

I was looking for a commuting vehicle, yes. Then winter came and I tried it out and it seemed to work so I kept going with it. Now it's become kind of a challenge to not miss a day of commuting (I'm into third year of consecutive days of having ridden the wheel to work -- closing in on 600 days.) To keep the streak going I can't allow cold temps to get in te way.

Anywho, I think I might have to rig up some sort of cover for the wheel over the weekend. When I left work the wheel temp was 42c (it had been charging), and by the time I got home it was down to 9c. This with an ambient temp of -18c. It didn't seem to be affecting performance any. The battery dropped from 83% down to 69% at the moment of arriving home, so 14% used to ride 6.5 km. But with ambient temperatures of -34c  in the mornings next week it seems like this might be a problem.

 

1872155446_Screenshot_20200110-163557_OneUIHome.thumb.jpg.41fc26926d953acc962e028fdce56294.jpg1542663185_Screenshot_20200110-163549_EUCWorld.thumb.jpg.76af205b0a0ea762786679f0ee1131ca.jpg
Edited by winterwheel

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"Better be safe than sorry." Don't do it. -30C is extreme. The operating discharge temperature range for Li-ion is typically from -20C, but charging it below 0C is a death sentence. Such extreme cold will bring the battery temperature below 0C in minutes even if you start from room temperature, and at the cruising currents of 5-10A the heat generated by internal resistance is just several watts, which is nothing for a massive brick in such extreme cold. So, since you will be braking, the battery will be charging at extremely low temperatures and it will die a quick death. That regen braking involves very high charging currents, which is double-bad when charging at low temps, only adds an insult to the injury.

discharge-voltage-temperature.jpg

 

Edited by Aneta

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35 minutes ago, Aneta said:

since you will be braking, the battery will be charging at extremely low temperatures

That’s a good point. However, since most Li-ion vehicles are stating -10•C as the lowest operational temperature (without a time limit), perhaps short regenerative charging moments can be OK after all?

I have to re-read about the effects of cold charging.

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1 hour ago, Aneta said:

"Better be safe than sorry." Don't do it. -30C is extreme. The operating discharge temperature range for Li-ion is typically from -20C, but charging it below 0C is a death sentence. Such extreme cold will bring the battery temperature below 0C in minutes even if you start from room temperature, and at the cruising currents of 5-10A the heat generated by internal resistance is just several watts, which is nothing for a massive brick in such extreme cold. So, since you will be braking, the battery will be charging at extremely low temperatures and it will die a quick death. That regen braking involves very high charging currents, which is double-bad when charging at low temps, only adds an insult to the injury.

discharge-voltage-temperature.jpg

 

Yeah, not really planning to let the wheel temp get down too low. For the ACM2 the temp  dropped to about 10c by the end of my 6.6 km commute on a -34c ride. So I've been pretty comfortable riding that back and forth for the past two winters with lots of commutes in the -20 to -34 range. I found that the temp stays steady in that wheel down to around -20. The wheel seems to have handled it pretty well, it's coming up on 5,000 kms with most of that having been winter riding. I only use it for snow days now though, since I put the Kenda tire on it to get better traction.

The XL seems to cool down a bit faster though, maybe because it is tall and thin instead of short and thick compared to the ACM, as I found out today. For that reason I'm going to look at working out some kind of cover  for it for next Monday. I'll keep an eye on the temp and duck into a coffee shop if it starts getting down anywhere close to zero. Once I get through next week I'll know for real how the XL behaves in these temperatures and how much effort I have to put into protecting it from cold in different temps. 

 

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For reference, this article explains pretty simply the issue with charging the batteries below 0c: 

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

The main takeaway would be don't leave your wheel to freeze outdoors and then bring it inside and immediately hook it up to the charger. Let it warm up to  room temperature first.

Edited by winterwheel

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If u need a cover for the 18xl,try the bodyguard from the @fatunicyclist.Thats like a big warm hug for an EUC.

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1573331640_Screenshot_20200113-070833_EUCWorld.thumb.jpg.659b0eeb5da2dedc8f08075e0af5baeb.jpg    ===>  1832466139_Screenshot_20200113-073139_EUCWorld.thumb.jpg.811cf2ee197abebff0a6c0ec13d36701.jpg

Morning one in the books, it was only -26 at the time of my ride. I ended up taking the ACM2 today because we had 1-2 cm of snow fall overnight and that's the wheel designated for snow conditions.  As can been seen, the ACM2 holds the temperature much better than the XL did; on a significantly colder ride it only dropped 5C over the same distance. The top speed is only 26.7, this is a combination of somewhat snowy conditions and that I just don't ride the ACM2 as fast as I used to because it is a bit noisy and vibrate-y with the winter tire on it.

It's forecast to be -36 at 7am tomorrow so fingers-crossed we'll get at least one or two cold trips in this week.

 

Edited by winterwheel

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Sorry for being a bit off topic but in the 2nd EUC World picture - what do the 3 orange dots actually signify? I'm guessing power usage and that the last orange dot is the max power used but  does that mean you've still only used 1/2 the power available? Or can anyone point me at a nice easy to understand manual?

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58 minutes ago, mike_bike_kite said:

Sorry for being a bit off topic but in the 2nd EUC World picture - what do the 3 orange dots actually signify? I'm guessing power usage and that the last orange dot is the max power used but  does that mean you've still only used 1/2 the power available? Or can anyone point me at a nice easy to understand manual?

It looks to me like the dots represent AvgSpeed, AvgRiding, and Top Speed ... the same as the numbers below show.

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3 hours ago, winterwheel said:

It looks to me like the dots represent AvgSpeed, AvgRiding, and Top Speed ... the same as the numbers below show.

I feel a bit dumb for not spotting that. I'll blame it on early senility. :(

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@winterwheel You sir are amazing. I live in the Vancouver, BC area and we have a light dusting of snow today so I am back in my car. One excuse that I have however is that I don't want to potentially damage my shiny new Tesla (only wheel) so that is my main reason. I am so tempted to try it out when I see people like you though...

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3 hours ago, mike_bike_kite said:

I feel a bit dumb for not spotting that. I'll blame it on early senility. :(

Actually I kinda wondered too, but not enough to work it out until you mentioned it.

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3 hours ago, Nitecrawler said:

@winterwheel You sir are amazing. I live in the Vancouver, BC area and we have a light dusting of snow today so I am back in my car. One excuse that I have however is that I don't want to potentially damage my shiny new Tesla (only wheel) so that is my main reason. I am so tempted to try it out when I see people like you though...

Winter wheeling is surprisingly fun as long as you're dressed for it. Summer surfaces can get a little bit boring unless you go off road. In winter though, you get all sorts of interesting little challenges to solve. Anyone who skis at all would find it is a similar vibe, except without the hill. :)

Edited by winterwheel

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I thought I was crazy :w00t2: , but it's good to know there's some Edmontonians around to make me feel relatively sane  :whistling:.   Back to hibernation for me to dream of warmer days!  :sleep1:

Edited by Hunka Hunka Burning Love

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-34 (2)

Day 2 in the books. I wanted to take a long way to work (and make several passes over a certain bridge to get video) so I took the ACM2 again; some of the route was cycling paths through forested areas and I wasn't sure what the snow situation would be. All told I was out in -34c (steady) for about 37 minutes, and the ACM2 was like 'is that all you got?' Hopefully some of the video will turn out, the GoPro Fusion decided it had had enough about 25 minutes in.

Edited by winterwheel

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Here's a bit of the video shot on  the way to work this morning. Temp was -34c, the camera decided it had had enough shortly after this was shot.

Edited by winterwheel

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