crossbreak
1 MW
even 36V would be enough to join at least the 40mph+ club! but i'm waiting keen for the answer too...
if he connected 74V/20s Lipo, then the answer is obsolete
GNG, 1000W 48V BB-drive, $400
- Thread starter spinningmagnets
- Start date
if he connected 74V/20s Lipo, then the answer is obsolete
bzhwindtalker
100 kW
Only 14s so about 4kw in that poor motor. I did some more testing and it seems like the thermal/saturation point is well reached at 80 amps. The motor was really really hot after 20 min of top speed and wheelie tests. The top speed is only 52km/h, but the top gear is quite overgeared. The test was to check the power capacity of that inrunner and it seems like there is not much to be gained above 35A. Moving from 25 to 35 made more differance than from 35 to 80! So if you want to squeese the max power out of that motor you should go higher volts like christer and others did.
crossbreak
1 MW
That's nice to know.
did you make any torque measurement, like going up a hill and weight your bike with you? measure things is always better than making I guess, you know
did you make any torque measurement, like going up a hill and weight your bike with you? measure things is always better than making I guess, you know
guyavitov
1 mW
- Joined
- Jan 16, 2013
- Messages
- 10
I wonder if I hurt my motor or the efficiency of my setup is ok.
I run the GNG on 26" wheels, 20S lipo (74v)
12 fets lyen limited to stock settings (45A)
Now the cruise current is about 1200-1500w (on 35 to 40 km\h)
on 50 km\h I measured something like 3000w to maintain speed.
feels like the efficiency is pretty low.
look like my wh\km is around 40 to 45 wh, if I keep the speed on 35km\h on flat ground its something like 35wh per 1 km.
so from a 10ah 20S I get about 15 to 25km depends on throttle management.
I run the GNG on 26" wheels, 20S lipo (74v)
12 fets lyen limited to stock settings (45A)
Now the cruise current is about 1200-1500w (on 35 to 40 km\h)
on 50 km\h I measured something like 3000w to maintain speed.
feels like the efficiency is pretty low.
look like my wh\km is around 40 to 45 wh, if I keep the speed on 35km\h on flat ground its something like 35wh per 1 km.
so from a 10ah 20S I get about 15 to 25km depends on throttle management.
Cyclebutt
100 W
Or maybe a strong nylon/teflon pulley that would slip-on/glue/hammer, to the existing drive pulley in original 15mm width? Add as many pulley teeth as necessary to achieve a strong shell slip-on for the existing drive pulley. I'll take two, please.spinningmagnets said:bee, would it be possible for you to try and make a 14T with a 10mm bore, 20mm wide and a keyway?
spinningmagnets
100 TW
I like the TNC 95T /15mm pulley especially because its only $12, and would be a cheap experiment. I would bond two of them and shave to about 25mm...in my mind the #25 chain with a proper cover (vacuum formed?) would be fairly quiet and would be more affordable, but that solution has been defined and is available for anyone who wants it.
LightningRods and I have discussed our curiosity over how much benefit there would be to the extra holding power of the small 14T pulley if it was widened to 20mm from 15mm (30%?). If it was a poor performance result, at that point, the next step up would be to try 16T, 25mm wide, or both. Some have expressed that they believe 25mm would be a hair too wide to make a comfortable stance for them.
skyjungae's secondary-reduction upgrade from the weak 12T FW to the common, strong, and cheap 13T is the right thing to do, but that puts finding as much reduction as possible back onto the primary side.
I am also excited to try some of these new garage methods of 3D printing and silicone-mold casting, and a small GNG pulley is as good as any other project from which to learn a new skill. I don't even have a GNG, but I still want to know what is the narrowest and lowest tooth-count pulley that will not cause the belt to slip under max power?
LightningRods and I have discussed our curiosity over how much benefit there would be to the extra holding power of the small 14T pulley if it was widened to 20mm from 15mm (30%?). If it was a poor performance result, at that point, the next step up would be to try 16T, 25mm wide, or both. Some have expressed that they believe 25mm would be a hair too wide to make a comfortable stance for them.
skyjungae's secondary-reduction upgrade from the weak 12T FW to the common, strong, and cheap 13T is the right thing to do, but that puts finding as much reduction as possible back onto the primary side.
I am also excited to try some of these new garage methods of 3D printing and silicone-mold casting, and a small GNG pulley is as good as any other project from which to learn a new skill. I don't even have a GNG, but I still want to know what is the narrowest and lowest tooth-count pulley that will not cause the belt to slip under max power?
Jackrabbit
100 W
Could the output shaft of the motor be measured and a new pulley 3D printed out of resin that fitted over the shaft? You would need to increase the size of the larger pulley to maintain the correct ratio but using the original shaft as a spline would be much stronger than a keyway. I don't know how tough the resin is though.
LightningRods
1 MW
Cyclebutt said:Or maybe a strong nylon/teflon pulley that would slip-on/glue/hammer, to the existing drive pulley in original 15mm width? Add as many pulley teeth as necessary to achieve a strong shell slip-on for the existing drive pulley. I'll take two, please.spinningmagnets said:bee, would it be possible for you to try and make a 14T with a 10mm bore, 20mm wide and a keyway?
Given what a PITA it is to get the crummy stock pulley machined off, I'm actually starting to think this is sort of genius. The outer flange on the stock pulley is just a cheap washer that can be pried off. What you are left with then is a pretty ideal steel inner spline that a cast nylon outer gear is NOT going to slip on. SpinningMagnets and I have been back and forth on PM a lot about what the ideal drive pulley is. I'm liking the idea of a 20mm wide 16T. Even with a 5mm pitch I bet that sucker is not going to slip at 2 kW. My feeling is that it's more important to solve the belt wear issue than to get the motor matched to the pedaling cadence. Plus if we're going to sleeve the stock 14T pulley we need the extra diameter of the 16T to have something to work with.
A 90-100 tooth driven pulley will work fine with my longer sheets. A 120T is marginal. I may have to whip up an experimental set that are even longer to try running a 20mm wide 120T nylon.
I'll make up a CAD model of the sleeved 20mm wide 16T pulley.
justlooking
1 kW
-now its going the right way
i liked this idea from the start, and it will suit most people,
i liked this idea from the start, and it will suit most people,
mr.electric
10 kW
I have access to a water jet. I think the operator uses solid works. Anyone want to send a file to test out the water jet idea. Why not make them 20 mm thick so one piece per bike is needed.
LightningRods
1 MW
Miles said:
Yeah, I was afraid of that, Miles. The 16T is too close the same diameter to the 14T to allow for a sleeve with any strength to it. I'm glad I checked this thread before retracing your steps in CAD. Thanks for taking the time to draw that up.
20T. I really like the fact that with a well finished 20mm 20T, belt problems would be a thing of the past. The larger bend radius and all of that tooth engagement is very belt friendly. With a 20T driver the big 120T driven is going to be a necessity. Let's hope that the big inexpensive vinyl one that's widely available is decent.
I still want to cast these in industrial resin. Silicone molds create a glassy finish that the belt will love. If the sleeve lasted a year and kept the belt alive for the same it would be a pretty livable package. As tough as these resins are it might very well last longer than the rest of the GNG.
LightningRods
1 MW
mr.electric said:
Water jets do an amazing job. These would be a straight outside tooth profile though. There's no way to create the inner negative shape for the existing pulley to act as a spline.
LightningRods
1 MW
Miles said:
You could make it work. What I meant was that water jets have to cut all the way through the material. You couldn't cut 15mm into a 20mm part and leave a solid cap on the end. There are other ways to fill the cap in afterward. I think it's a good idea to have the 5mm extension solid rather than a tube. Stronger and easier to cast copies of.
The most important thing is finish. If the water jet can cut fine and clean enough it would be a good place to start. If you're going to be making a lot of copies of something you want the best possible pattern to start with.
LightningRods
1 MW
Miles said:
I like it! The end plate could be 5mm thick and not have the center cut out for the spline. Viola! Instant solid end cap.
How would you hold all of these plates together? Adhesive?
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