Pikes Peak, Electric Mountain Climbers...

[itchynackers]

Found this route player very interesting for those who really want detailed locations of steep areas...

http://connect.garmin.com/player/110423332

and...

 

[dogman dan]

Still think merely keeping up on a pos would be rubbing in real goooood.

Here's another data point for ya'll, trying to get it through to you guys that the right winding, (whatever it trurn out to be for the majority of the race grade) makes a difference. In my dirtbike riding up crazy steep hills, the low speed winding wins every time in the hubmotor class. For this even slower climbing of even steeper hills my 2812 motor is simply kickin ass and taking names.

I just rode a 5 mile route, for aproximately 30 min. Long enough to really heat up a motor. Average speed was 8, yes no shit, 8 mph. Allmost entirely uphill, the "flat" parts are only 10% grade. The route includes portions that are several hundred yards long of 20 degrees, not percent, degrees baby. And included the first ever no getting off and walking ascent of the 30 degree slickrock that's 50 yards long by an ebike. Pretty close to the equivilant of riding up a blue square ski slope.

Here's the interesting part. Pulling 70 wh/mi, in 70 f weather, no wind, no bike speed to create cooling, the motor reached actual equilibrium temperature in about 15 min. Then hovered at 145F to 150 f. This is measured by axle temp, and adding 40F to that. Axle temp sucks as the temps are climbing, but once they do reach equilibruim they are accurate enough. That axle is, after all, part of the metal your winding is wrapped around. Cover measurements mean little, but I was able to put my hand on the cover, for a short time. At the worst part, after the big slickrock, the lyens 12 fet was hot, but not too hot to touch. I saw lots of 2500w readings on the CA along the way, when I could snatch a look while riding up a rock staircase. Pretty impressive that I could push 2500 w into that thing for any length of time, riding at the max speed you can stay on a bike on a rock staircase, 3-5 mph, and not flame the motor immediately.

What's going on? The slow winding motor is simply making that wattage into motion instead of heat, even at 5 mph! There is no other explanation for it. The right winding makes the "sweet spot" where less heat is made wider in my opinion.

I think you find the right winding to pull 70wh/mi up 10% grade at 25-30 mph and you will not exeed 250F equilibrium temps. And you won't smoke the motor till about 300-400F.

Bear in mind, I'm no jockey, and I wasn't pedaling hard on this ride. Just 190 pounds hanging on for dear life on this ride.

 

[dogman dan]

So that graph is pikes peak, same route as the bike race? Looks like most of the time, you are at 8-10 %. With crazy steep spots at the switchbacks as usual.

 

[neptronix]

I've decided, I'm going to buy my own damn magic pie for a 16" kids bicycle tire, mill the edges, put fans it, upgrade the phase leads, run premium hall effect sensors and run it on my dyno at a steady load, slowly increasing power until it smokes. We know an X5 can't do 1kw, geared hubs blow at <500w continuous, I bet the open and fan cooled magic pie does better than 4x what an X5 can sustain.

 

[itchynackers]

Yes, I converted lowco's ride data to a .gpx (gps) data file and ran it through graphing software. This is his actual recorded data. It looks like he removed the original elevation profile chart, so I made another.

 

[dogman dan]

Sweet!, Nothing beats the real world data.

 

[neptronix]

It would be hilarious to draft the optibikes all the way until the last 10% of the race and then let it rip.
But you know they like to play dirty and crash into people even at the start of the race
Their drafting is a dirty trick.. if some of you actually make it out here, we'd have to do that.. switch bikes back and forth to cool off our motors.

cell_man, i would love to see your results. I am 95% confident in the dual MAC setup i proposed and would love to take those up the mountain. But i'm 100% confident in the magic pie idea. Would be nice to build two bikes and have another rider work for me.. but i don't know anyone around here.

dog_man: that is impressive about your 2812 motor. I have played with the ebike.ca simulator for many many hours and the key for low heat and good efficiency seems to be:

1) highest RPM possible ( smaller wheel ). Electric motors seem to love as high rpm as possible.
2) lowest speed winding possible, and highest voltage possible ( widens the efficiency band.. reduces amps needed as well )
3) not ever dropping out of the efficiency band. So a narrow range of speed is unfortunately necessary.

So you are close to ideal with your getup but i wonder what massive volts in a 20in. wheel with that motor would do.

 

[neptronix]

By the way, to whoever's coming.. you will want to stay here for at least a few days before the race, if you live anywhere near sea level.

Adjusting to the altitude can leave you panting walking up a short hill. It took me and my lady about a week to acclimate. We were dizzy and out of energy for the first few days. We came from 100ft above sea level, so the change was drastic for us.

Fortunately there is a lot to do here. Garden of the gods, ridiculously long bike paths along the river, snow in the mountains, hippie tourist towns, insane military museums, parks, etc.

 

[gensem]

The regular Pie is a good option, right?
Wouldnt a bigger goldenmotor like the MW16C -- High Power Motor
be a better options? its cheap and rated for at least twice as much power and its not that heavy.

 

[neptronix]

That motor is an interesting curiosity - it looks like it will fit on a regular bicycle.
But the magic pie is far taller. Look at how on the 16" rim, it fills out the rim almost to the point where you are wrapping the tire around the hub motor itself.

It's much like the issue with the crystalyte x5. Huge magnets and great peak power but not much in the way of surface for cooling.

 

[itchynackers]

Anyone have any data on typical weather in late August at Pikes? I'd like to get a rough idea of temps from 10000' to 14000' above sea level.

 

[gensem]

That motor is an interesting curiosity - it looks like it will fit on a regular bicycle.
But the magic pie is far taller. Look at how on the 16" rim, it fills out the rim almost to the point where you are wrapping the tire around the hub motor itself.

It's much like the issue with the crystalyte x5. Huge magnets and great peak power but not much in the way of surface for cooling.

Neptronix this is supposed to be a motorcycle hub motor, so they must be using 16" MC rims wich are pretty much the same size of a 20" bycicle wheel, so that motor should be tall too...

Talking about a tall motor, drop Hal a line, he might be able to fix you one of thoses, but I dont think its going to be cheap.

 

[neptronix]

Is that a crystalyte HT/HS?

 

[gensem]

The left one is a clyt x53 the other one is much bigger. Hal and Accountant got this from the same factory(I think, im not sure) that does the motor for this "bicycle".

The "bicycle" in thoses pictures is using 24" wheel and the motor is not so big hahaha, but the magnets are supposed to be very big, over 50mm

 

[liveforphysics]

Brompton.

If I get one, it appears I can just fly out anytime I want and make a practice run, because it will fit in my luggage!

They fold up extremely small!

Then, for the real race, I ship out the pink bike miles found with the optibike frame shape.

 

[dogman dan]

Didn't somebody on some thread, maybe this one, say the temp at the summit was near freezing this year? Or near freezing wind chill at least?

Mountain August weather in Colorado. Could snow, or the asphalt melt. Most likely is at 6000 feet at the start it will not be much over 85F. 95 tops. By 10,000ft, room temp or lower. By 12,000ft, it could easliy be 50f, but could be still room temp if it's under conditions of a stagnant high pressure. Any kind of weather, like a thunderstorm, and you could quickly find your self riding in rain, snow, or hail piling up inches deep. At 14,000 feet, it's always going to be cool. So by the top, you should be seeing your motor temps back off from the equilibrium they had lower down.

 

[John in CR]

The air is cooler, but there's a lot less of it for the same reason of altitude. The heat risk may actually be greater up there.

 

[veloman]

The air is cooler, but there's a lot less of it for the same reason of altitude. The heat risk may actually be greater up there.

I know there's less oxygen, but what does that have to do with cooling? You're still going to have cold wind blowing over the motor, cooling it constantly.

 

[amberwolf]

The air is less dense. Less air = less heat conduction away from any object being air-cooled, unless you increase the volume of air moved past it to compensate.

The more molecules actually coming into contact with the surfaces, taking away a bit of energy, and moving off, the faster it cools things.

This is one reason that liquid cooling often works better than air cooling, for peak load cooling purposes. (it isn't any better for long-term continuous cooling unless you're either vaporizing the liquid and carrying it off in the air, or you have something immersed in a very large amount of the fluid, like in boating applications).

Their drafting is a dirty trick.. if some of you actually make it out here, we'd have to do that.. switch bikes back and forth to cool off our motors.

Unless you can make sure the motors shed heat faster than it was generated (like a human body can) then the drafting probably won't help--it'll most likely actually make the problem worse, because the motors will continue heating up inside faster than they are cooling off, and do so even faster since the lead bike's motor will always be using extra power (and wasting more power because of that as heat) to "tow" the other bike it's windshadow.

 

[liveforphysics]

The air is cooler, but there's a lot less of it for the same reason of altitude. The heat risk may actually be greater up there.

I know there's less oxygen, but what does that have to do with cooling? You're still going to have cold wind blowing over the motor, cooling it constantly.

The air doesn't pick and choose its gasses and decide to filter out O2 at higher elevation.

There is lower air pressure, lower air density, which means for a given volume of air that passes by your windings, there is less mass of air to be heating, meaning it increases temperature faster, and since you can only transfer thermal energy while there is a temperature difference, it can't cool at the same rate.

 

[John in CR]

Here's a simple graphic I got from an Ericsson paper about the problems associated with cooling electronics at altitude. It factors in the inherent reduced temperature that comes with increased altitude. It looks like near the top of PP our motors will shed about 20% less heat than at the bottom.

 

[neptronix]

Nice find John!! i had no idea.
The dual MAC idea is out the window 100%.

If yall are scared off from doing this now.... just come anyway. Watch me shoot plasma out of two magic pies halfway up. lol.

 

[veloman]

Man, that is weird. I would never of thought that cooling would be affected by altitude.

Nep, do you notice if you go downhill faster there? You should, though it's probably only 1 or 2mph difference, due to the lower air density.

 

[veloman]

The air is less dense. Less air = less heat conduction away from any object being air-cooled, unless you increase the volume of air moved past it to compensate.

The more molecules actually coming into contact with the surfaces, taking away a bit of energy, and moving off, the faster it cools things.

This is one reason that liquid cooling often works better than air cooling, for peak load cooling purposes. (it isn't any better for long-term continuous cooling unless you're either vaporizing the liquid and carrying it off in the air, or you have something immersed in a very large amount of the fluid, like in boating applications).

Their drafting is a dirty trick.. if some of you actually make it out here, we'd have to do that.. switch bikes back and forth to cool off our motors.

Unless you can make sure the motors shed heat faster than it was generated (like a human body can) then the drafting probably won't help--it'll most likely actually make the problem worse, because the motors will continue heating up inside faster than they are cooling off, and do so even faster since the lead bike's motor will always be using extra power (and wasting more power because of that as heat) to "tow" the other bike it's windshadow.

It makes total sense now, I just didn't think deeply enough about it.


Regarding the drafting, I'm pretty sure the lead guy can go a hair faster with someone drafting him. I certainly never noticed it slowing me down when I was a lycra in racing or group riding at 30mph. I think the airflow over the lead motor wouldn't be significantly more than the rear guy, since the motor is not in full direct wind anyway, being a rear wheel. But of course, a 5% difference could be a huge deal.

 

[liveforphysics]

In swimming (one of the sports I did through HS and college), drafting is mutually beneficial to both people as long as the rear swimmer is extremely close to the front swimmers feet (yet as the front swimmer your perception is that you're moving slower due to feeling less turbulence on your feet). After the front swimmer is a few feet ahead, it only helps the rear swimmer and has no negative effects on the front swimmer.

I don't know enough to speak for cycling, but I would take a wild guess that it would be similar.