Author Topic: E-Bike developments  (Read 105305 times)

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AzCal Retred

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Reply #30 on: May 30, 2021, 08:30:25 pm
I was always told - "If you're hungry, you'll eat it!"  ;D ;D ;D
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Nitrowing

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Reply #31 on: May 31, 2021, 01:26:22 am
At least he gave it a try...

https://hackaday.com/2021/05/30/bicycle-flywheel-stores-a-bit-of-energy-not-much/
"results perhaps serve as a solid indication of why it’s not something we use particularly often on bicycles"
No wonder we no longer have a motor industry


AzCal Retred

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Reply #32 on: May 31, 2021, 06:00:26 am
The reason it isn't very helpful is inappropriate technology. We don't use steam trains anymore. PV arrays surpass Solar-Thermal plants in output and operating efficiency. Beacon Energy has been building spun carbon fiber flywheel energy storage modules for many years. They run at over 22,000 RPM, spin in vacuum on maglev bearings. Power is added or removed from the core electronically via a brushless inductive process. This guy did a nice job of building a demo, but you can't make "did work" or "didn't work" assumptions based on a crude model using inherently limiting tech. A real problem with a useful flywheel in a vehicle is mass & gyroscopic precession. Serious gyro's need to be gimballed. Bolted on solidly and spun up to maximum, you could literally have a vehicle that wouldn't turn, or would hang rigidly in space by a wheel if you went down an incline.

My favorite - Professor Eric Laithwaite gives a demonstration of a large gyro wheel
https://www.youtube.com/watch?v=JRPC7a_AcQo

https://www.youtube.com/watch?v=GeyDf4ooPdo

https://www.youtube.com/watch?v=0L2YAU-jmcE

https://beaconpower.com/islands-isolated-grids/
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AzCal Retred

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Reply #33 on: May 31, 2021, 06:20:46 am
Axman88 @ #26: " I do find it ironic that it often seems, that those most free of any time constraints, most absent of any need to be anywhere at any particular time, the retired community, seem most certain that they require the ability to travel at 60 or 90 mph, then take half the day so doing, only to return at the end of this time, to the same place they started "
A valid point. As I age out, I find the 70+ MPG, 22 HP, 55ish MPH speed of the Pre-Unit Bullet appropriate for my "needs". There are several available 250cc machines that replicate this performance envelop at 100 pounds less weight. A 300 pound H2 fuel cell e-bike with a 300 mile range and 35 - 45 top end should be doable. Probably an additional 100 pounds of batteries could give you a machine that covers 150 miles between charges.

The question I have is why do all this instead of just using a "renewable" hydrocarbon fuel like bio-diesel, alcohol or bio-gasoline? The energy storage capacity of these liquids is proven. Hydrocarbon chemistry can make virtually any compound given appropriate feedstock. Chemical Recycling of plastic is available tech and produces essentially "crude oil" if the process is built for that output. Wouldn't it have to be cheaper to  use synthetic recycled hydrocarbon fuel than completely rebuild the transportation infrastructure?

https://en.wikipedia.org/wiki/Plastic_recycling

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Nitrowing

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Reply #34 on: May 31, 2021, 01:10:05 pm
"you can't make "did work" or "didn't work" assumptions based on a crude model using inherently limiting tech."
Affordable tech.
Yeah, a serious flywheel setup wouldn't allow him to go around bends  ;D
No wonder we no longer have a motor industry


axman88

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Reply #35 on: June 05, 2021, 06:51:39 am
I was researching recovery rates for regenerative braking on electric vehicles, when U-tube decided it was appropriate to offer me a look at this fellow's bicycle flywheel experiment.  https://www.youtube.com/watch?v=gahKxbwUcYw

It certainly does look like it works, and could even be a quite useful gadget, if one's route consisted of lots of long, straight downhill runs, with busy cross streets at the bottom of the hill.   But, the gyro effects and extra cost, complexity, and mass seem to make it impractical for the average rider.

As far as recovery rates for regenerative braking on E-vehicles, my impression is that this feature is not much more at present than a something for salesman to point out, "WE got it, and theirs ain't!"  Even highly advanced Tesla isn't saying much more in print than, "it theoretically COULD be as high as, ....".   The calculation involves multiplying out all the efficiency factors for the various conversions, chemical / electrical x electrical / mechanical x drive train efficiency, then squaring that, because at BEST, the same efficiency factors apply to recovering the energy.  In the real world, I suspect the flywheel would recover a higher percentage of energy than regenerative braking, because motors are optimized to convert electricity to mechanical power, not visa versa, and because the two least efficient energy conversion steps don't apply to flywheels.

Reports of real world experiments with vehicles equipped with the regenerative braking feature were suggesting numbers like 15 -20% had been attained, and that the system is only really practical when one is traversing long downhill runs, where braking is required for safety or to meet legal restrictions.  In general, a much better strategy to conserve energy, is to do what comes natural on our human powered vehicles, when faced with an imminent stop, start coasting.

Such a strategy would make one extremely unpopular commuting in a car in an urban setting, one is expected to drive the speed limit, regardless of what lies 100 feet down the road, but there is more freedom for the bicycle.  Since I've started riding bicycles again, I find that there are long stretches on my work commute, where a 60+ year old man on a bicycle can, over a distance, easily keep up with vehicle traffic.  It's classic turtle and hare, I pass them in their stoplight queues, and they pass me between the lights.  Sometimes this happens 3 or 4 times in a row.  I was very surprised to find that after only a week of bicycle riding, I was able to match, or beat my automobile commute time.   Once I go electric, I think this will become absolutely no contest in favor of the bicycle.


Arschloch

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Reply #36 on: June 05, 2021, 08:32:35 am
KERS..kinetic energy recovery system,  I believe the Formula 1 used some mechanical system employing a flywheel, adding a boost of some 60-80 hp when exiting the corner.

Probably the F1 regulations don't allow the use of engines of adequate horsepower.

In electric vehicles and bikes it doesn't cost any extra hardware to add the KERS function, which is why mostly all large manufacturers will have it included. It might be a bit challenging to implement it in a way so it remains unnoticed by the rider.


Richard230

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Reply #37 on: June 05, 2021, 02:42:01 pm
I was researching recovery rates for regenerative braking on electric vehicles, when U-tube decided it was appropriate to offer me a look at this fellow's bicycle flywheel experiment.  https://www.youtube.com/watch?v=gahKxbwUcYw

It certainly does look like it works, and could even be a quite useful gadget, if one's route consisted of lots of long, straight downhill runs, with busy cross streets at the bottom of the hill.   But, the gyro effects and extra cost, complexity, and mass seem to make it impractical for the average rider.

As far as recovery rates for regenerative braking on E-vehicles, my impression is that this feature is not much more at present than a something for salesman to point out, "WE got it, and theirs ain't!"  Even highly advanced Tesla isn't saying much more in print than, "it theoretically COULD be as high as, ....".   The calculation involves multiplying out all the efficiency factors for the various conversions, chemical / electrical x electrical / mechanical x drive train efficiency, then squaring that, because at BEST, the same efficiency factors apply to recovering the energy.  In the real world, I suspect the flywheel would recover a higher percentage of energy than regenerative braking, because motors are optimized to convert electricity to mechanical power, not visa versa, and because the two least efficient energy conversion steps don't apply to flywheels.

Reports of real world experiments with vehicles equipped with the regenerative braking feature were suggesting numbers like 15 -20% had been attained, and that the system is only really practical when one is traversing long downhill runs, where braking is required for safety or to meet legal restrictions.  In general, a much better strategy to conserve energy, is to do what comes natural on our human powered vehicles, when faced with an imminent stop, start coasting.

Such a strategy would make one extremely unpopular commuting in a car in an urban setting, one is expected to drive the speed limit, regardless of what lies 100 feet down the road, but there is more freedom for the bicycle.  Since I've started riding bicycles again, I find that there are long stretches on my work commute, where a 60+ year old man on a bicycle can, over a distance, easily keep up with vehicle traffic.  It's classic turtle and hare, I pass them in their stoplight queues, and they pass me between the lights.  Sometimes this happens 3 or 4 times in a row.  I was very surprised to find that after only a week of bicycle riding, I was able to match, or beat my automobile commute time.   Once I go electric, I think this will become absolutely no contest in favor of the bicycle.

I have been riding electric motorcycles for the past 12 years and I can tell you that the power generated by the motor and put back into the battery on a motorcycle when slowing is not very much. My first two electric motorcycles had a device that kept track of the regeneration effect and on my other motorcycles I just estimated the impact of regen based upon any increase in the battery's displayed State of Charge on the instrument display. Under normal riding conditions you can expect about a 1% to 3% range increase from regeneration. The higher figure would result from city travel, with a lot of stop and go riding.  However, cars can do better, apparently due to their greater mass and more powerful motors, which results in the manufacturer being able to up the regen without worrying about the tires skidding on wet pavement.
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Richard230

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Reply #38 on: June 06, 2021, 01:47:50 pm
In the future when you are riding electric motorcycles and want to make modifications to them, you can look forward to modifying something like this.   :o

Happy wrenching!  ;D
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Arschloch

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Reply #39 on: June 06, 2021, 01:54:44 pm
In the future when you are riding electric motorcycles and want to make modifications to them, you can look forward to modifying something like this.   :o

Happy wrenching!  ;D

Yup, you are going to have to be Albert Einstein to figure it out.  ;D

....and no time for lunch.


Nitrowing

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Reply #40 on: June 06, 2021, 02:42:17 pm
Going to have to wear thick rubber gloves too  :-[
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GlennF

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Reply #41 on: June 07, 2021, 01:57:07 am
If only you could still buy the Roper Steam Velocipede ...







« Last Edit: June 07, 2021, 02:01:44 am by GlennF »


zimmemr

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Reply #42 on: June 07, 2021, 02:25:05 am
If only you could still buy the Roper Steam Velocipede ...







This is one I did a small amount of work on. The builder was an engineer at Lycoming, and did ride it for short  distances. It's owned by Connecticut Antique Machinery Association and is on display at the CAMA museum in Kent Connecticut.


Nitrowing

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Reply #43 on: June 07, 2021, 03:32:36 am
This is one I did a small amount of work on. The builder was an engineer at Lycoming, and did ride it for short  distances. It's owned by Connecticut Antique Machinery Association and is on display at the CAMA museum in Kent Connecticut.
That looks awesome  8)
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Richard230

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Reply #44 on: June 07, 2021, 02:11:59 pm
That is really cool!  ;D  But probably hot when it is running.  ;)
2018 16.6 kWh Zero S, 2009 BMW F650GS, 2020 KTM Duke 390, 2002 Yamaha FZ1