NEW FR-DH E-Bike project >3Kw

panurge said:
Waiting for components, I have the time to speculate: is a 18:1 ratio from motor to the wheel a good ratio for up-hill?
Jules,

You need to work back from the torque capabilities of the motor.

The Astro 3220 is rated for 5.3Nm continuous torque.

5.3Nm * 18 = 95.4Nm.

Allowing for torque lost in the drive, let's say that's 90Nm continuous torque available, at the wheel.

Assuming a gross weight of 100kg, or less - with 90Nm torque on a 0.66m dia. wheel, you'll be able to get up any hill you're likely to encounter......

You might like to play with this spreadsheet:
http://endless-sphere.com/forums/viewtopic.php?p=312555#p312555

See also:
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=6892&p=287797#p287797
 
Thanks Miles for your suggestions....beautifull calculator/software

Obviously my datasheet was overall intended for better understand the thread, because numbers are better than my english :D

Miles said:
The Astro 3220 is rated for 5.3Nm continuous torque.

5.3Nm * 18 = 95.4Nm.

Allowing for torque lost in the drive, let's say that's 90Nm continuous torque available, at the wheel.

Assuming a gross weight of 100kg, or less - with 90Nm torque on a 0.66m dia. wheel, you'll be able to get up any hill you're likely to encounter......

Are these assumption valid for the max torque at 7500 rpm (48v 94A on a 4 turns at 33MPH)?
but what if 4000 rpm 17,5 MPH or less? can anyway get up any hill?

Jules
 
With this type of electric motor, the amount of torque, potentially available, is inversely proportional to the percentage of the no-load speed the motor is running at. So, max. torque at stall, zero torque at the no-load speed. The maximum continuously sustainable torque output is dependant on heat dissipation and is usually much less than half of the stall torque.

The motor speed will rise or fall until reaching the equilibrium point, where the load matches the available torque.
 
Here's a graph showing the output of the Astro 3210 10t at 44V

file.php
 
Thanks Miles for the pics and the interest....

I know drivecalc, it's a great tool, but where can I get datasets for big motors like astros or HXT, there is a repository or something similar? in my database there's no one of them...

Another thing....do you think guys that a first stage 6:1 reduction (like 11-66) is something reliable, possible (Matt?)?

Thanks to ES and to all you guys

Jules
 
I just start a "New motor" and enter the Kv, motor resistance and no-load amp values that are given in the available specifications...

You have to be careful with pulleys which have low tooth counts. The torque capacity drops off pro-rata when you go below 6 teeth in engagement... I would use a minimum of 16t, and even then you'd probably need some form of torque control.
 
Miles said:
I just start a "New motor" and enter the Kv, motor resistance and no-load amp values that are given in the available specifications...

Ok start new motor :oops: ok easy, but cannot well understand where/how to put no load values :oops: and a lot of blank fields.....mmmmm when saved he says very small load range... :oops:

I only have the two data sheet in the astro pdf ther's something i miss?

Miles said:
You have to be careful with pulleys which have low tooth counts. The torque capacity drops off pro-rata when you go below 6 teeth in engagement... I would use a minimum of 16t, and even then you'd probably need some form of torque control.

So for you 6:1 with 11 to 66T isn't reliable even with a centrifugal clutch?
clutch + torque control seems to be a bit complicated...
but if I can manage a max 2.5:1 ratio from jackshaft to the wheel, (consequently min. a 5:1 first stage ratio) this allow for a small cog (like max 24t) and a decent pedaling with a relatively small chainring.
My original Idea was 11:66 + 12:24 for motor line and 38 thr\\u 12 to 24 for pedals, but I understand that maybe is not achievable....

Jules
 
panurge said:
Ok start new motor :oops: ok easy, but cannot well understand where/how to put no load values :oops: and a lot of blank fields.....mmmmm when saved he says very small load range... :oops:

I only have the two data sheet in the astro pdf ther's something i miss?
The no load amps go in the RH column, the voltage it relates to in the LH column (For the Astro, I've assumed it's the nominal voltage). Leave the middle column blank.

Just ignore the warning messages :) You might have to swap propellers if the graph doesn't appear...

All the data is in the Astro pdf.
 
Ok Miles this was really usefull for me, thank you very much, now I have datasets for Astros, for HV castle ESCs and batteries...super

It would be great to have a Drivecalc software with wheels and human/vehicle weights instead of props...

As I promise this is a Cad snapshot of the prototype....can't wait for all components :x ....I have to resist in start machining the downtube-batbox....I would have the Astro3220 motor tomorrow in my hands but I have to wait weeks....damn!!!

https://picasaweb.google.com/panurgos75/Bikes#5611163990782336994

(The drive/cranck plates are referred to the first reduction Idea that was around 15-18:1 from motor to the wheel in a single jackshaft drive).

Jules
 
Jules,

You might be interested in this:
http://www.mitcalc.com/en/pr_tbelts.htm
http://www.mitcalc.com/doc/tbelts/help/en/tbelts.htm

I also use the Conti-Tech software. It seems to have a few anomalies/bugs, though....... I always cross-check with MITCalc...
 
Thanks for the SS Miles, I checked it out, looks pretty neat.

When you mentioned the Nm for the 3220, was that just a quick back-of-the-envelope calculation to see if he'd be able to get up the hill?

Can you point me to calculations that show how to figure what power would be required to go up a given grade at a given speed?

Thanks,

Katou
 
katou said:
Can you point me to calculations that show how to figure what power would be required to go up a given grade at a given speed?
You can use the Powercalc spreadsheet to see that: http://www.endless-sphere.com/forums/viewtopic.php?p=312555#p312555 :)
 
You may want to look at the 'goldenmotor' site in red china... they have some nice looking big motors that also turn a lot slower, better suited for bikes. Hall effect sensored for proper motor controls too. RC controllers are kind of sketchy, if you ask me.

I understand your feelings about the pedals. I bought a used Zero MX, which has no pedals. It is more motorcycle than bicycle and weighs about 140 lbs. I'm sure you have heard of these. I actually wish it did have pedals, as silly as that may sound, because I see it as a way to get the bike out of a trail if something happens to the electric drive train, or it plain runs out of juice. Even pedals/cranks that are detachable and thrown on a rack or backpack would be great for this limp home mode. Not so important if you don't ride trails, obviously.

Other thing about bigger bikes that don't look very bike-like : they attract more attention on trails you may be riding where the grey area of ' no motorized vehicles allowed' can be a problem. I removed most of the plastic from my Zero, and covered the remaining white plastic with green camo. Because it does not make the usual motor bike sounds, the general public does not look at it, even as I take a shortcut through a park/playground going a slow 2 mph. Adults ignored it, only the ocasional boy looked and knew this was something unusual. Wearing a goofy bicycle helmet helps too ;)
Seems the camo and lack of noise lets it go.
But I'm sure park rangers would bust me.

I am going to build a much more 'bicycle looking' e-bike to take on mountain bike trails, where the Zero would not 'look good'.
Anyhow, just some thoughts.
 
Hi Lesdit
Thanks for your interest....
but I did not quite understand your suggestions....you say goldenmotors.....obviously in my research for motors I looked also for chinese manifacturers but just for knowledge....My Bikes are made from scratch, entirely in Italy....I buy only fork (Marzocchi from italy or RS or Fox), brakes (Formula from Italy or Avid) and guarnitures...also full-Ti hubs and rear shock are "homemade" here....so buy the "core" of the project (motor) in PRC would be not the best choice in my mind....anyway if I had found something that fit my needs and preferences....

But 11Kg (this is the NET weight of GoldenM) is near what I have in mind to use for ALL the power system (motor-batteries-esc-boards-wires-throttle-drive).... :)

I well know the Zero bikes as the Quantya, I have tryed those bikes (motorbikes) an especially Quantya really impressed me....but are a bit expensive and a lot heavy, 90Kg.....my Husky is just 115Kg with 54 Hp....obviosly not electric but with 100km of full power and only 30 seconds to refill :D

Jules
 
Yes, that is the fact.
Right now, nothing can compare to the energy density of liquid fuel.
You have to ask yourself why you are going electric.
For me, it's the lack of noise, and it's just plain fun. Not carbon footprint for the bike. ( My house runs on Solar, I drive a Prius that's soon to be a plug in, I'm doing my share with low carbon )

panurge said:
I well know the Zero bikes as the Quantya, I have tryed those bikes (motorbikes) an especially Quantya really impressed me....but are a bit expensive and a lot heavy, 90Kg.....my Husky is just 115Kg with 54 Hp....obviosly not electric but with 100km of full power and only 30 seconds to refill :D

Jules
 
In fact i'm intersted in a BIKE conversion and not motorbike.....I think (and I dream) that everything human have invented (without the clear intention to harm the biosphere :( ) may find it's right use...I like technology but would like technology follows intelligence..... :)

I am a frame builder/developer and for me this build is like a "toy"....my bikes are used for freeride-downhill and the frame I choose for the conversion is a 2002 old frame that I really love, and also after these 10 years it looks really recent, due to it's strange, unusual and innovative design....if i put it on the market today I'm sure it will meets the favour of a lot of people...(would be also strongly criticized of course, for the same reasons).

From 2002 I (and the guys that worked into this frame) look the bike and we say: she misses only the motor.... :wink: I remember that in the 2004 we was interested in a wankel motor to fit in :mrgreen:

Some months ago we decide to go electric....and cause we build frames with lightness and style (personal)in mind...we was thinking about the lighters vehicles (electric) in the sphere....this led us direct in RC flight....I found ES googling around RC flight motors.....

RC seems for a newbe like me, complex and not already reliable, but in these few months in the ES, and learning with friends and web, I'm convinced (for my expectations) that RC is a way that worth to be followed...not maybe the best, maybe a bit dangerous (Lipo reputation) and dangerous to ride but as y say I have an 89s Husky and also an old yama rd500 2 strokes that are not really easy to handle.....

In my projects there is also a pedelec that fits europeans laws, and I plan to use on it A123 batteries and an "easy" 500w power system in a front Ti-Carbon XC frame...but is another history and not near..

The IDEA of this FR-DH E-BIKE is different: Up-hill in paved or unpaved road to reach the Start point of a DH track an then switch off motor and downhill with a bike that is manageable like a late 90s DH bike (25Kg) but with new components.. :D ..the battery box will be easy removable, so you can theorically change battery when discharged, at the end of the track, put it in charge, an mount another charged pack to continue the fun....

If I really reach this objective, I may think about offer this kind of fun for guests, In my small bikepark, where untill now we have to uphill bikes&bikers with my Landcruiser....ther's no liability problems, because every guest already signs a release of liability to use tracks/bikes and the tracks are in a private area.....we are speeking about DH...it's an extreme sport.....

I know, the project is ambitious, like a lot of the ES's projects (for this I'm posting here)....but also my first frame build it was....and no-one of my friends trusted that frame would become real....but after 13 years I'm here always building frames....and let me say: for the pleasure of doing it, and to make ideas materials, certainly not for money....as market is not my strenght, and don't want to pay a manager for this.... in the firsts building years, when I tryed to sell frames for money intentions, the big Italians and foreign frames brands have always trying to steal my ideas and discredit my home-made brand....In fact more than half of my frames have been given like for free to very young guys who wanted to start the Gravity career.....

Luckily I have a different business/interests: a forestry bio-farm (with wind, solar and biomass as energy sources and a small trekking-bike-motorbike park here in Tuscany), and my family obvious... now with the new entry...my beautifull son...

Have a nice day and life

Jules
 
Miles said:
Jules,

You might be interested in this:
http://www.mitcalc.com/en/pr_tbelts.htm
http://www.mitcalc.com/doc/tbelts/help/en/tbelts.htm

I also use the Conti-Tech software. It seems to have a few anomalies/bugs, though....... I always cross-check with MITCalc...

Sorry Miles, I have not thanked you for the useful MITCalc software..... :oops:

Thanks :wink:

Jules
 
Miles said:
That's ok. I'm glad you found it useful.

Yes it's helpful for me, I have not the same experience in drives as in structures, Dynamics and materials and I don't know software for drives and transmitions cause I never had the need for them....I have the abitude to use the knowlwdge of the people near me for everything I can't well understand....the best way to learn, save time and maybe money....but unfortunately nobody here in Italy has skills on High powered RC E-bikes...

For who is interested, this is a part of the E-project but also a part of the actual DH frame line...a video of an early stress test for the 2-chambers air shock with 250mm exc. :

http://www.youtube.com/watch?v=3kcbYmkkjVM
 
Hi all

Waiting for Recumpence's components, I looked around for other candidates parts of the project, like centrifugal clutches, gearbox, power supply etc.

Until now I bought used for cheap prices the followings:

3 used drives (including centrifugal clutches, variators torque corrector ecc....) one from a 75cc 2str. racing moped and 2 from damaged scooters, a 150cc 2str. and a 200 cc 4str.

A kart centrifugal clutch from a friend with #35 sprocket and 5/8 bore

A neugart PLE80 8:1 gearbox from an old CNC servo

A used LiteOn interesting power supply rated for 24/48v at 20/10Amp
liteon2.jpg

Have you guys info about this device and the best way to use it?

I have a 3phase 380v 16KW grid connection in my farm and I have found a 380v imput switch with 24/48v 40A/20A output for a reasonable price what do you think about for a super fast charge....(12s 20Ah Lipo's)?

It would be helpful, projecting the drive with a clutch, to know the torque value near the stall for the Astro 3220 4t and not only the max continuous torque at 7500rpm....better, a torque output graph from stall to no load speed.... :)
Miles said:
The maximum continuously sustainable torque output is dependant on heat dissipation and is usually much less than half of the stall torque.
I.E. Assuming this "much less than half" as a 35%, the stall torque could be near 15Nm...

Any suggestion/comment will be appreciated

Jules
 
Back
Top