Nuvinci developer kits for cheap

I'm pretty sure that a few dozen design engineers would stand aghast at just my bike, made out of pieces of what they created, much less all the other projects of various kinds I've had over the years. :lol:

I have a feeling that actually having continuous shifting would end up being less efficient than using some certain number of shift points, depending on the vehicle design, terrain, traffic, etc., but I don't know.

It'd have to be tested both ways, and that would require a separately-designed shifter controller that really did continous shifting. That would be relatively easy, as it doens't even have to be MCU-controlled, and can be entirely analog from op-amps or even transistors, simply reading the current flow at teh battery and/or motor phases, vs the actual speed of the system, vs the demanded speed, and shifting as much as is appropriate to keep that current down to some pre-specified level.

I'm not quite sure how to design that circuit, as I'm not great at engineering things, only at adapting bits of existing designs to my own purposes. ;) But it *sounds* easy enough that I'd bet a number of ES members could do it in their sleep. :lol:

BTW, it doesnt' have to be a complete shifter-motor controller, it only has to have the analog 0-5V output to run into the existing shifter's analog manual override input, and you could then switch between continous automatic shifting, and shift point style.

I assume (can't remember) that the shift points are changed to by up/down commands or lines, so you could still use the simple analog device described above to read the speed/current/throttle and issue a shift up or shift down command by changing the value of the shifter's inputs.

Does that maek sense? (I'm really tired, so I cant' tell..I re-read it a bunch of times and it gets more confusing each time; I'm afraid to change it).
 
My reason for wanting manual shift is so that I do not use up any battery at all. I am planning on putting it in an electrathon. This is a battery limited race. So any battery used up shifting would not be available for motion.
 
Got mine already! The hub itself is over 8 pounds, very similar to a geared hubmotor of the same size.

Shipping this out EMS to Australia would be $120. Priority would be $60 if I can fit it securely in a large flat rate box.

Most other countries will be the same.
 
GGoodrum said:
I've decided what I'm going to try as my setup. I am going to use a 3220 with one of Matt's v4 drives, with the 20 m wide belt and the torque limiter. Matt says this is good up to about 9kW, which is more than enough. What I will do is get this with an extra long shaft so that I can use it with an ENO freewheel coupled to two of the adapters I did for the direct drive setup I did a while back, which will hold one freewheel to the pedals on one, and a track cog on the other that will drive the Nuvinci.



Once I get the Nuvinci (it is supposed to arrive on Friday, which is also my birthday, so this will be a nice present. :)), I'll start a new build thread in the Non-Hub section.

-- Gary
Click to expand...

Gary, I would strongly caution you on using a 9KW set-up on this hub, assuming that all 9KW of power would reach the hub, because 9KW / 750W = 12HP! :shock:

I'm sure there are some losses in the reduction, but NuVinci recommends no more than 7HP continuous IIRC, and I know from reading on the Motorbicycling forum that gassers have had the N171B (same hub that should be with this kit) start slipping at 9HP, so somewhere between 8-9HP is where it starts to slip internally.

There is a liquid in these hubs that compresses to act as the momentary "solid" as it compresses in a microscopic gap between the power transfer discs (input and output) to the balls in the middle, and if you exceed this torque, the liquid will allow things to slip.

[youtube]4n15N6yS2dE[/youtube]

Fortunately with electric motors we have less spiking general in the power transfer than with a gas motor, so we have less chance of spiking the input torque and such to the point of causing slippage.

Another good thing is even when the internal fluid got hot and discolored, and the torque was exceeded to the point of slipping, there was no internal wear or damage noticed on the CVP's internal parts, but replacing the fluid is a bit tricky, as it is a very special one developed for Fallbrook Tech, and last I saw, no one found anything off the shelf to replace it, so it's something you would only want to buy from Fallbrook.
 
johnrobholmes said:
This will bolt to the disc mount of the motor. The internal freewheel will be fixed to allow for reverse rotation, or else I will use a DD hub.

http://endless-sphere.com/forums/download/file.php?id=61968


The design allows for freewheeling of the cranks, rear hub, and motor so that any combination of power can be used with no extra spinning parts and minimum drag. A bit bulky, but it solved chainline and power issues at the same time for me.
Click to expand...


I'm very interested to see how it works for you JRH! :D

So glad there will be so many smarter people than me running these hubs so I can learn from you all. :wink:

I'm still confused why you have three sprockets with your hub motor as jack-shaft though, could you not just have the pedals going to it with a freewheel, and a fixed cog going from motor to hub?

Since a freewheel at the hub will allow the pedals to freewheel, and when you do turn the pedals it will turn the hub motor as well giving your pedals a connection to the in-put of the hub, I'm not getting the need for a third FW or cog? :?

P.S. Also don't forget, the NuVinci it's self will freewheel internally, so a freewheel at the hub is not needed, however with only two chains going to your hub, there will be the drag of the motor as it turns when you pedal, but this is nothing compared to the increased wear any freewheel that is used in transferring power from motor to hub. And IMHO, better to not have any freewheel at all on the motor driven chain for longevity & safety's sake.

It was explained to me by a tech from Fallbrook that the freewheel adapter added to the N171 series hubs was just extra insurance, but not needed as the hub it's self will freewheel internally.
 
OH! One more note:

The NuVinci will allow you to shift under load, but it's fighting you the whole way, and more power is put to it, the harder it is to shift. Even with just pedal power, I have noticed when I am really standing on the pedals from a stop or up a hill that it will not shift very fast or hardly at all under high load.

This of course is more pronounced the more power you put to it, and so one thing that would need to be considered when mapping any kind of automatic shifting that you're going to have to back off or completely release the throttle while it's shifting.

IIRC the newer 360 is supposed to shift better under load and when I demoed one locally, it was smoother, and also would shift under load, but too much load caused it to bind up (this is just with pedal power) similarly to the N171B 350% hub, so you will need to figure out how to adjust throttle settings.

I also would agree that setting pre-set shift points is kind of defeating the purpose of the CVP, since it has infinite "steps" or individual ratios with-in it's range, and if I were to use this electronic shifter, it would make most sense to have it mapped to give a constant pedal cadence that also agreed with your motor's RPM, or just have two buttons to make tiny up or down "shifts" to get to the ideal ratio for current conditions.

I have found it very useful that I am running a motor at about the same RPM that agrees with my pedal cadence as it gives me instant feed-back as to how efficient the motor's RPM's are, since I know when it's too hard to pedal along, and I just adjust, and with the correct single stage reduction from motor to hub, this also means you're keeping the motor in it's most efficient range.

I believe this is the single largest reason I was able to go the same route on multiple occasions from Oregon City to Portland, OR, (about 20 miles round trip) and get the same work out of my motor while using only about 33-35% of the normal Whrs.

I'm really excited to see what you guys come up with! :twisted:
 
I have three sprockets/ freewheels on my jackshaft because I need to move the chainline over. I am sure I could get away with less if I planned to use a freewheeling crank. The freewheel shown just allows the pedal power to freewheel past the hub body so there is no drag, it doesn't actually have a chain connected to it.


I'm not really interested in the CVT aspect of these hubs, nor the electronic shifting. I'm just interested in the power handling and gear ratio for the price. With even a 1hp motor, more than 6 shift points would mean a lot of time spent shifting. I could see the CVT being useful for dialing in the perfect cadence all the time, maybe I could work on that down the road.
 
johnrobholmes said:
I have three sprockets/ freewheels on my jackshaft because I need to move the chainline over. I am sure I could get away with less if I planned to use a freewheeling crank. The freewheel shown just allows the pedal power to freewheel past the hub body so there is no drag, it doesn't actually have a chain connected to it.


I'm not really interested in the CVT aspect of these hubs, nor the electronic shifting. I'm just interested in the power handling and gear ratio for the price. With even a 1hp motor, more than 6 shift points would mean a lot of time spent shifting. I could see the CVT being useful for dialing in the perfect cadence all the time, maybe I could work on that down the road.
Click to expand...


Yeah, it's a great hub! I would use it simply because of it's robust design (at least three shops here in Portland, OR have said they have never had to warranty these hubs for anything internal, some people broke the external cable mounting housing in crashes or dropping the bike on it, but nothing internal) that has been very trouble free.

I wonder, has anyone looked into what it would cost to get this hub and add the cabling & mounts to allow it's use with the manual shifter too? Might be nice to have both options. :)
 
For what it is worth- With my order I requested a replacement bottle of the traction fluid, Juli (from Nuvinci) replyed that they could not supply it, no suggestion as to where I could obtain replacement fluid.
 
JEB said:
For what it is worth- With my order I requested a replacement bottle of the traction fluid, Juli (from Nuvinci) replyed that they could not supply it, no suggestion as to where I could obtain replacement fluid.
Click to expand...

Hmm that is not good, I'll have to do some digging and see where I found the info before about it on the motorbicycling site and see how they got some. IIRC, Valvoline makes it but it's a special blend that was made specifically for Fallbrook Tech's needs.

I won't be able to do that till late tonight, but if you search "nuvinci" on their forum I believe it's a thread called "Inside the nuvinci" where I got this info, might also be the same thread that has the information on how much HP they were able to put to it before slipping occurred.
 
http://www.fallbrooktech.com/valvoline_THreadable.pdf
http://www.iuvmag.com/articles/jan07-1.htm
http://www.fallbrooktech.com/06_tf_FAQ.asp
http://motorbicycling.com/f48/inside-nuvinci-hub-21827-3.html
but I didn't find anywhere to buy it in my 30-second search. ;) Hopefully there is a source in that last link somewhere; I haven't had time to read it.

Here's the sort of basic block diagram of the autoshifter control system I was describing in text previously.
 
Couple of people have talked about using this transmission in efficiency-crucial applications, which doesnt seem quite right to me. They're a friction transmission, which means to me some non-zero amount of slip at whatever speed/load; and even if I'm wrong about that, the efficiency figures I've seen quoted for them aren't that high (was it ~80% IIRC?). Horses for courses, this is a very cool automatic CVT, but it's not an ultra-efficiency transmission, is it?

Then the other bit about not wasting power in shifting, my gut feeling would be that the amount of power used in shifting the internal mechanism would be tinyscopic compared to the amount of energy used by the main drive motor. I'm sure we can figure out how much power it uses over time, and I haven't done that, but I'd think it'd be saving a similar percentage as switching off the headlights on an ICE car. Worthwhile as the last percentage that you're saving, but not the first priority, and especially if you're using what I believe is quite a lossy transmission.

Not wanting to switch off the main drive motor every few seconds while the transmission shifts just a tiny amount to an infinitesimally different ratio makes more sense to me, FWIW.

Eric
 
@Li-ghtcycle: Thanks for the tip, but I'm not going to put more than about 4-5kW through this. I asked Matt if that was a problem and he said, no, that he's put as much as 9kW through the belt drive/torque limiter.

@JRH: My site is still not back up and running yet, but PM me your address and I'll send you one to try. It looks just like the one in your drawing, except the threads are only long enough for one freewheel.

I'm thinking I might do something a bit different on mine, and just put one of FFR Trike's 13t Odessey freewheels, with their adapter, on the end of Matt's v4 output shaft, and then put it inline with the pedal chain. This requires using crank with a freewheel, but the bike I want to put this on already has one.

I'm thinking I will setup two shift maps, one with just three shift points, for the motor, "low" gear, 1:1 and then an orverdrive/high gear. The second shift map will be for pedaling only, and will use all 64 steps. I'll use a handlebar-mounted rocker switch to select between the two. With 4-5kW available, I don't need a lot of extra gearing. Also, since this is going on a 20-inch folding bike, I don't need it to go over about 30mph. I tried about 35-40mph once. It took about 10 minutes to let go of the seat. :shock: :mrgreen:

I think my Nuvinci showed up today as well, but I'm down in SD for the weekend, so I won't be able to do anything until next week.

-- Gary
 
@Erogo, I agree with your points; mostly I was trying to think of all the reasons people might want to reduce shifting and list them, just to see what they are. :)

My own reason is not really wanting to cut power in traffic to shift, for the most part.

I got my tracking number a bit ago today, shows the label was created but package not yet at UPS. Says shipping weight is 15lbs, which sounds like a lot, until I compare it to what's estimated for all the rest of the bike. :lol: Guessing it'll be here mid-week next week.
 
can you guys post some pictures of it? i thought it was a hub but apparently not? where does it go and wherewould an electric motor go? what motors are recommended for this tranny?
 
It is a hub. Fallbrook's site (linked in a few places in the thread) has all the data on it, and there are pics of it (including disassembled!) in the links to another forum's discussion of it on the previous page. ;)
 
Erogo said:
Couple of people have talked about using this transmission in efficiency-crucial applications, which doesnt seem quite right to me. They're a friction transmission, which means to me some non-zero amount of slip at whatever speed/load; and even if I'm wrong about that, the efficiency figures I've seen quoted for them aren't that high (was it ~80% IIRC?). Horses for courses, this is a very cool automatic CVT, but it's not an ultra-efficiency transmission, is it?

Then the other bit about not wasting power in shifting, my gut feeling would be that the amount of power used in shifting the internal mechanism would be tinyscopic compared to the amount of energy used by the main drive motor. I'm sure we can figure out how much power it uses over time, and I haven't done that, but I'd think it'd be saving a similar percentage as switching off the headlights on an ICE car. Worthwhile as the last percentage that you're saving, but not the first priority, and especially if you're using what I believe is quite a lossy transmission.

Eric
Click to expand...

My aplication is an electrathon. Total wieght is about 330 lbs. By rules I am limited to 2 optima Yellow Tops. It is an effecincy contest, but it is also a race. Currently I use an Etek motor and a sprocket and chain. Top speed is around 30 MPH. I know that the Nuvinci will not be as effecient as a chain with no transmission, except that the nuvinci will allow me to shift to a lower gear for quicker acceleration with less power. On an oval track it would do no good. But many of our races are on street courses with lots of turns that you need to slow to about 12 MPH to navigate. I will do a lot of testing of this before I put it to use in a race enviornment. I haven't lost a race in 2 years, and am not about to throw a game changer in like this without proper testing. I am hoping that the gains of a lower gear for acceleration, the ability to overdrive to a higher top speed will give me an overall effeicency/speed boost.

As for how much power the servo motor uses is an unknown, trust me I will test it and if it uses too much I will make it work manually.

If it proves to not give me an overall effeicency bonus in the Electrathon, then I will build my street racer around it. 8KW of motor and a transmission should make for one hell of a fun machine.
 
Drewjet - awesome. Those projects sound like fun! good skills. And your purchase was obviously a lot more thought through than mine :) Im still scratching my head when my girlfriend asks me what I'm going to use it for. Umm - my commuter? I just thought they were too cool :)

the shift actuator says it draws up to 5 amps I think. (@ 12v?) but for how long?
 
Probably a couple seconds at a time at most; I'd guess much less than a second for short shifts.

The motor they are using is much like a car window motor--it uses a worm gear in it to spin the shift actuator, so the motor has to spin quite a few times to spin the actuator even once. Since the actuator has to be spun around somethign like two full turns (IIUC) to shift from highest to lowest ratio, shifting all the way up or down probably takes more than a second.

But if you use all 64 shift points, and they are evenly spread, then if you were accelerating and the shifter has been setup with something to tell it to shift automatically at various speeds, it'd be shifting just a very short time but very often.

If you only use say, 5 or 6 points, evenly spaced, and do the same thing as above, it'll shift for longer each time but less often.

Theoretically the latter will take less total power to do, in the shifter motor, as the surge current of starting up the motor is probably a lot more than running it for a bit, especially compared to such short bursts of power. So it should be more power-efficient to have less shift points, for the shifter motor. It is probably not as power efficient for the traction motor, though. ;)

I'm not totally sure of any of this, but mine should be here on Wed and I'll find out more then. ;)
 
I did some spoke fitments today. Looks like 12ga is what they are drilled for. 13ga isn't a bad fit. 14ga is like a hotdog in a hallway.


I would recommend 13/14 butted spokes for bicycle type builds, and 12ga for moped type builds. I was really hoping I could get away with a super thin spoke on these to shave weight, I will start digging for 13/15/14 butted spokes. Unfortunately we will probably not find them in the length needed because of the high flange diameter.
 
I've decided that in order to get something going as quick as possible, I'm going to resurrect my [urlhttp://endless-sphere.com/forums/viewtopic.php?f=28&t=12267&p=447348#p447348]3220 direct drive setup[/url], on a 20" folding bike, and replace the existing Sturmey-Archer 3-speed with the new Nuvinci setup. I think it might be challange, though, to get essentially two freewheels to fit side-by-side, on the end of the Nuvinci. We'll see.

-- Gary
 
Looked what came in today, crap this thing is heavy. I plan to put it on my spare tidal force frame with an RC drive, but it will be quite a while before I even get to it. Other builds have priority. If it wasn't for the price, I would have second thoughts due to the weight. Good thing this is suppose to handle some power or else I would never have considered it.View attachment 1
 
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