Over 65mph on 20s see pg 4

General Discussion about electric bicycles.
John in CR   100 GW

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 11 2012 3:34pm

Update. I took another spin without my backpack, which has a rigid bottom so is about 1sqft of suction at the back in a tuck. At a lower status of charge I hit 65.4mph as a top speed. The reason I tried again was to bring my GPS along this time. It was getting turned off and on in my pocket, and didn't capture much of the ride, but a nice clean uninterrupted stretch it showed 108kph just as I was about to slow down for an off ramp, so unless you average over a significant distance a GPS simply doesn't have the accuracy to measure speed accurately over just a single segment. The only way that's correct is if my rear tire expanded significantly at those rpms. ie If someone says "GPS certified" about a top speed, simply ignore it.

I'll take the word of my CA instead. I measured the circumference of my wheel with me aboard and measured the distance from valve stem at 6:00 to 6:00 1 rotation and entered that in my CA, so I know it's accurate and slightly conservative compared to at speed. It's not conservative enough for thst 108kph to be correct when I know for a fact I was slowing down.

john7700 wrote:WOW :shock:
Thanks for posting and be safe.
J
Thanks for the support and concern. This was out on the dead smooth highway cleaned by yesterday's rain, and very little traffic. The bike was tracking like on rails, so I was as safe as walking out to the mailbox to check the mail while wearing a hardhat at safety glasses. :mrgreen: Really though, I've never had a bike feel so good at speed. The perfectly round tire and balancing it to no vibration at all spun up to 1300rpm, was such a pleasure to ride that I think I'll up the voltage and post the number the other high power hubbie users have been dreaming about.

When I do, I'll make it a task impossible for lesser hubbies, and after miles of WOT running I'll go straight into an 8% grade climb followed by a several miles of shallow up hill grade. Sure they might be able to put a flyweight cyclist type on a bike and reach the same or better speed with extreme voltage over a short sprint, but no way they have the efficiency to run at high speed for long, a simple fact of life when using inferior iron.

BTW, I did today's run with less than $200 in controllers, so it's not a spend the big bucks achievement. Anyone can do it.

John

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Re: Over 65mph on 20s see pg 4

Post by itchynackers » Aug 12 2012 6:37am

I've always said that about GPS readings. Just not reliable/accurate. Anyway, looks like a monster. I was gonna ask if you were going to the Pikes race next year, but I didn't see a chain on there! Would be nice to see a few of these motors sprinting up the mountain. Opti may have to create their own class of ebike to win.
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John in CR   100 GW

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 12 2012 7:44am

itchynackers wrote:I've always said that about GPS readings. Just not reliable/accurate. Anyway, looks like a monster. I was gonna ask if you were going to the Pikes race next year, but I didn't see a chain on there! Would be nice to see a few of these motors sprinting up the mountain. Opti may have to create their own class of ebike to win.
We took the chains off all of our ebikes. It leads to better questions and less confusion. Pedaling a high power ebike is silly, and we have no intention to pretend being a pedal bike. They could have pegs and would still be classified the same as a bicycle here, actually better than a bicycle as they are prohibited on some of the highways while my ebikes are not.

My son is back stateside and has family near Denver, so you never know. There would need to be classifications though, since it really wouldn't be fair. Your run was a challenge riding right at the limits with a great result, and we wouldn't want to put any damper on that kind of fun effort. With a motor like this it would be simple and only a matter of having enough batteries, because we've already done steeper climbs than the Peak at greater speeds with less powerful and less efficient motors than this one. Maybe the trikes would make it interesting with their advantage in the curves, but they'd have to come with more power. Once I get this motor ventilated, so I can really turn up the power, I'll do a demonstration. By then I'll have video capability, but I need to do some real stress testing in stock form first. From now thru the end of September it's pretty much daily rain, so other than some dry mornings here and there, progress gets slowed way down.

John

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Re: Over 65mph on 20s see pg 4

Post by Trackman417 » Aug 12 2012 12:20pm

Who cares if you got up to 60 plus mph? It's all about how fast you got to that speed :mrgreen: for all I know you got up to 60mph in just about a minute flat. (I am joking, obviously :lol: )
We're you hauling ass all the way up to the 60mph mark? You forgot to leave that little detail out, unless if I missed it :oops:
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John in CR   100 GW

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 12 2012 4:08pm

Trackman417 wrote:Who cares if you got up to 60 plus mph? It's all about how fast you got to that speed :mrgreen: for all I know you got up to 60mph in just about a minute flat. (I am joking, obviously :lol: )
We're you hauling ass all the way up to the 60mph mark? You forgot to leave that little detail out, unless if I missed it :oops:
Fairly quickly, which is more quickly than any cars or motos that I've run across with this motor on, but not as quickly to 50mph as when I had Hubmonster on this bike, but I was pumping 425A peak into it. I won't be comfortable turning the controllers up that high until after I remove the motor and ventilate it, probably next weekend. I'm only running 190A peak input right now, and these controllers are set to a somewhat soft start.

While you're waiting for me to crank it up, think about how many hubmotor driven ebikes do 65 with ease with a 250lb beached whale aboard, or in a 19.2" wheel, much less at 74V nominal. No rain yet, so your post is a good excuse to get in another ride and see if the GPS will info will satisfy our curiosity, since I don't know the answer either. :mrgreen:

John

PS- Keep in mind that any ebike takes some time to get that last few MPH on the way to top speed. It's just the nature of the beast due to the shape of the torque curve and influence of BEMF.

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 12 2012 6:22pm

Trackman,

I made an effort, but there was too much traffic for any kind of proper speed run, and traffic forced me off the throttle a number of critical times, like right as I was entering the highway on the initial few hundred yards of dead flat. After slowing to below 20 on the ramp I was well above 50mph before the merge, and that's only 100yds or so. The only really interesting info was 700 yards of 5.5% grade holding 59-60mph, and 400 yards of 7% grade holding 54-55mph, which surprised me. This motor loves WOT. Much of the 2.5 mile climb was spent in bunched up traffic, and none in a full tuck, so I can't wait for a light traffic run to do 6-7 miles of continuous WOT with flat and uphill grades the entire way. :mrgreen:

John

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Re: Over 65mph on 20s see pg 4

Post by itchynackers » Aug 12 2012 7:37pm

Hopefully you have a temp sensor to get some reliable data. They are fairly easy to install. The hand method may not work for all models of motor.
9c 9x7f w/ 12awg phases
9c 8x8r w/ 10awg phases, temp sensor, vented
9c 6x10r w/ 10awg phases, temp sensor, liquid cooled, 3rd Place Pikes Peak 2012!

"Don't argue with the galactically stupid...they drag you down to their level and beat you with experience"

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Re: Over 65mph on 20s see pg 4

Post by toolman2 » Aug 12 2012 7:55pm

following our discussion earlier here and trackmans questions, surely an excellent measure of real performance is acceleration over say 100m :!:

its kinda easy to do if you just record the ca screen from 0 to near top speed and your done, later you can look at the now logged data to see the entire acceleration curve.
from that we could pick out the 100m? time and also a bunch of further info, really really informative and it would start to give us something comparable for folks everywhere with all sorts of machines.

it would be worth including the total weight, (you could compare again with a lighter rider john :mrgreen: ) and that then contains masses of good info, but if we start to form some kind of standard (like 1/4mile for cars) then we can all acctually get it when something is really quick, compared to the same excited comments for mr noob and a 9c :D

lets start the bar low with my pie, 4000-4500w in, 130kg total, 0 to 100m in 9.1sec, doing 58kph over the line.

dam it would be good to get some times for different bikes that we all know, i know its not in top form yet for accel john, but give it a go to get an initial start point, and then we can start hassling others (like say luke) instead of you. :lol:

by the way, you prolly know already, more weight doesn't affect top speed(much), just how long to get there.

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 12 2012 10:17pm

itchynackers wrote:Hopefully you have a temp sensor to get some reliable data. They are fairly easy to install. The hand method may not work for all models of motor.
These motors are wired with a 95°C thermistor, so no sensor needed. I haven't tripped it yet, and that's all the data I need. The only way I would feel temperature data was necessary for my motors would be if I was selling ventilation mods, but I don't. I don't run my motor hot enough for stator temp to be a meaningful bit of data.

I see performance as the bottom line of all data, and stator temperature is too small a piece of the puzzle to worry about unless you're having heat problems. Wh/mile is the most significant number to me. Riding hard and under heavy loads like steep ascents, the higher the figure without heat failure, the greater the power out and/or heat dissipation. That means in terms of high performance the higher the better over a reasonably significant distance. In terms of efficiency, obviously the lower the wh/mile the better for the same average speed, assuming no net change in elevation, and no wind or pedal assist.

John

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Re: Over 65mph on 20s see pg 4

Post by flathill » Aug 12 2012 10:24pm

Thats a nice looking hub/wheel
When is hubmonter.com going live?

aluminum frame at 65mph?
Might want to at least upgrade to the super v dh frame with a top brace if you dont go steel
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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 13 2012 2:09am

Interesting, though I'd be afraid to weld anywhere near the head tube. The main tube on mine is solid fiberglass+epoxy on the inside from the BB up past the top tube with the top tube partially filled and the plug tapered toward the headset to avoid a clear line of extra rigidity. There was a previously repaired crack at the shock mount, so I wanted to make that entire area incapable of collapsing.

I do inspect around the headset and main tube regularly. Is there a known weakness in the SuperV from the head tube down to the top tube? I stick to good roads that I know and don't hit potholes or do jumps or anything, so the biggest forces the front sees is during braking. I think I'm way under the design limits except for the extended seat mount I have.

I'll get a custom steel frame done soon, which should cut a lot of weight from what I have not, but your post has me thinking I should speed that up. Full triangulation with 4130 is the plan, and copy most of the geometry I'm so used to with the SuperV.

Thanks for the concern. You have me thinking now.

John

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Re: Over 65mph on 20s see pg 4

Post by flathill » Aug 13 2012 4:12pm

do not weld a top brace in unless you plan on having it done by a pro and will have your whole frame heat treated and quenched properly
I was saying it might be worth it to swap the whole frame to the down hill version with the top tube from the factory
but if you are already planning a steel frame...then no worries :D

I have two Al frame bikes with heavy gussets but I don't go over 40mph
Al is great but it is not forgiving of minor flaws and can/will eventually become brittle as it never stops precipitation hardening
not really something to worry about unless your talking really old frames
also by the ocean: http://en.wikipedia.org/wiki/Stress_corrosion_cracking
it might be time to retire that frame if you have seen any signs of cracking
especially since you are building stealth motorcycles

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Re: Over 65mph on 20s see pg 4

Post by hillzofvalp » Aug 13 2012 6:49pm

You did say that you were using the same peak battery output correct? U say 11% efficiency gains but want to make sure you weren't running half the peak output power for those numbers.

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Aug 13 2012 10:35pm

hillzofvalp wrote:You did say that you were using the same peak battery output correct? U say 11% efficiency gains but want to make sure you weren't running half the peak output power for those numbers.
Settings have little effect. Same speeds & same bike & same loads = same energy out required. If energy in is less, then it's more efficient. I've handicapped the new motor by being sure I'm riding faster, so in reality I am getting more energy out at the wheel, but still have less energy in. I ride so many of the same routes on a daily basis (eg every morning the 4 mile round trip to the grocery store for fresh stuff for the day), that I'm exceedingly familiar with consumption before and after...even wrt to how much more it takes on the return than on the way due to the slight downhill ride there. With the old motors I've always gotten the same consumption despite drastically different settings. All use the same voltage, and I ride the same speeds. My cargo bike at 80A gets the same wh/mile on those routes as Hubmonster did at a 425A battery limit. The cargo bike is more aero, but it loses some efficiency by accelerating so much more slowly with a speed wind motor.

Another example of how current limits affect consumption very little if you ride the same speed, is that in my normal errand riding, the change from a 210A to a 425A battery limit with Hubmonster had no effect on wh/mile. My wh/mile stayed right at 61-63wh/mile before and after on my grocery store run. That was with a few hard launches during the ride as long as I stayed in the same speed range. Now when I rode out the acceleration to higher than typical speed or otherwise rode harder than normal, then consumption went way up, because I was using more power overall at the wheel.

For efficiency comparisons, don't think about power on tap, but instead focus on energy. That's how I can make these statements with confidence.

HOV, I intentionally err significantly on the side of conservatism when I post about things like performance. I'm intimately familiar with my bikes and their performance over the same routes, but go ahead and keep trying to find a hole.

John

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Re: Over 65mph on 20s see pg 4

Post by hillzofvalp » Aug 19 2012 11:45pm

I hear ya. I want one kinda.... When will you post video? Pics of internals?

What is the spacing of the motor? 180mm?

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Re: Over 65mph on 20s see pg 4

Post by John in CR » Jan 11 2013 4:36pm

Motor is now on sale. I'm even bribing the earliest adopters of the best hubmotor on the planet. Sale thread is here http://endless-sphere.com/forums/viewto ... 31&t=46898

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