Post Your Acceleration Numbers

[grandmasterE]

As I'm going through the forums trying to evaluate the pros and cons of the different systems, I'm finding it a bit tough to collect any semblance of empirical data, and I'm finding it a bit frustrating to compare peoples setups. What about a thread with no questions, no off topic, no nothing except:

-motor
-controller
-battery
-wheel size
-total weight (ebike plus rider as tested)

-and-

-acceleration numbers (0-10 mph time and 0-20 mph time)



I suggest 0-10 mph and 0-20 mph times. I think most can hit that. Anything more than that is great, but how about those as standard.

I think this could be valuable to put some numbers together to study. Any thoughts?

E.

 

[gogo]

There's a post somewhere about using a card in the spokes and recording the sound to generate the acceleration and speed data. That combined with consistent graph scales would be a great way to compare different setups. Then if someone could whip up a nice web based interface to do graph overlays, we'd be in business.

 

[BVH]

Too many variables for the "card frequency system" to work.

size of wheel
Number of spokes
Spoke spacing
Spoke pattern
distance of placement from center of hub
card material

Probably more.

 

[tostino]

Too many variables for the "card frequency system" to work.

size of wheel
Spoke spacing
Spoke pattern
distance of placement from center of hub
card material

Probably more.

If you have a good mic, and everything set up correctly it should be just as accurate as a normal speedo, the only difference is you can't see your speed in real time.

 

[gogo]

The card in the spokes would work well until you get "card float". Then you have to double up.

 

[Drunkskunk]

there ought to be a way to hack the Cycle Analyst to give these numbers.

 

[tostino]

there ought to be a way to hack the Cycle Analyst to give these numbers.

A stop watch and looking at the CA . However, I don't think it would be very accurate. At slow speeds, wheels turn slower so the delay between speedo updates is higher. That is, if you are using the in-wheel speed sensor, and not the motor one.

 

[JS Tyro]

Put more magnets, evenly spaced, on the spokes. Then connect the Hall sensor to a microcontroller and program it to calculate speed and acceleration. For around $50, everyone can answer this poll with greater accuracy.

Alternatively, get a GPS module that has a higher update rate than 1Hz - there are 5 and 10Hz units out there. Plug it into a computer/microcontroller and calculate speed anc acceleration. This would be about $100-$150 (cheaper if you use an existing computer and only need the GPS).

Get an accelerometer sensor and connect it to a microcontroller. Around $100.

Of course, this is all tongue in cheek. But this would work.

 

[morph999]

check out this if you want to get an idea of what motors do what

http://ebikes.ca/simulator/

(might need firefox to view that)

 

[morph999]

The crystalyte 5305 goes 0 to 20 mph in about 5 seconds at 48v.

 

[gogo]

Here's the post I was referring to:
Motor testing without a dyno.. or even a tach..

The cool thing about the sonic method is that its cheap!

 

[vanilla ice]

If somebody (op?) is willing to do the sound analysis, all us ES'ers could post up mp3's with spoke count and tire OD data.. would it work?

size of wheel tire oD.. but easy enough to measure. 1 minute.
Number of spokes again takes about 1 minute to count.
Spoke spacing Card placed as close to the rim as possible, would this be an issue?
Spoke pattern Card placed as close to the rim as possible, would this be an issue?
distance of placement from center of hub see above.
card material standard playing cards should be accessible to all
Probably more. what else?

 

[John in CR]

As I'm going through the forums trying to evaluate the pros and cons of the different systems, I'm finding it a bit tough to collect any semblance of empirical data, and I'm finding it a bit frustrating to compare peoples setups. What about a thread with no questions, no off topic, no nothing except:

-motor
-controller
-battery
-wheel size
-total weight (ebike plus rider as tested)

-and-

-acceleration numbers (0-10 mph time and 0-20 mph time)



I suggest 0-10 mph and 0-20 mph times. I think most can hit that. Anything more than that is great, but how about those as standard.

I think this could be valuable to put some numbers together to study. Any thoughts?

E.

E,

I get the vibe that you're looking at getting into the biz. If that's the case, how about doing your own research instead of handing to you on a silver platter?

John

 

[docnjoj]

0-100-0 in 7 seconds! Oh, U mean bikes!?
otherDoc

 

[docnjoj]

Check with Doc Bass re: bike acceleration if the is a non-commercial venture for info only, Grandmaster-E!
otherDoc

 

[grandmasterE]

clipped

E,

I get the vibe that you're looking at getting into the biz. If that's the case, how about doing your own research instead of handing to you on a silver platter?

John

I am just trying to evaluate what equipment is out there and how it performs so I can make an informed decision when I make my next purchase. I tend to (over)analyze things, and I like having as much data available as possible. Having said that, I find that members on this forum are (understandably) more interested in top speed than acceleration, and I also find that the lack of standardized testing makes effective evaluation very difficult. I’m just trying to get an understanding of how the products compare to each other for how I anticipate using them. I don’t care (much) about speed over 25-30 mph, but I do like brisk acceleration.

I also think there if we had enough data, we might actually start to notice trends like which motor works best with which controller for instance. The problem is we need more empirical data to be able to do this, instead of just anecdotal evidence.

If you’re asking why I don’t just purchase one of each motor/controller/battery and test them all myself, I guess my answer is that I can’t afford to do that, although I would love to. Think of the graphs!

As for you implying that if I was interested in making something for this market I shouldn’t have anything handed to me…well…I think you need to rethink that! I think we need to welcome commercial interest! Imagine what kind of changes could be incorporated into some of the existing products if companies ever took the time to listen to the end user! How does it help you or anyone else on here to bristle if you think someone is trying to make a product? You’re telling me that we’re better off driving interest away from this market? For all the complaing on the boards about how much more customer focused some of the Chinese ebike parts makers need to be, I'd say that based on your reply, maybe it's a two way street?

In the end I guess it doesn’t matter as my thread has been hijacked by nincompoopery, so I guess I know what the level of interest in having actual data is.

E.

 

[docnjoj]

grandmasterE
Since you do appear serious about this acceleration data acquisition please DO see Doc Bass's early experiments using an accelerometer and crude but effective strain gauge! It applies mainly to Crystalyte motors, however but at fairly high voltages. He just set a world record, I believe!
otherDoc

 

[Doctorbass]

According to GPS dataloggin

0-40km/h in 1.7sec
0-72km/h in 4.3sec using the drag bike setup ( 15kW)
0-80 in 6sec
0-94.3km/h in a bit more than the 1/8 miles line
1/4 miles in around 18sec

5302 on 20"
18 fets controller
100V 172A max
total weight 230lbs

 

[gogo]

In the end I guess it doesn’t matter as my thread has been hijacked by nincompoopery, so I guess I know what the level of interest in having actual data is. E.

I suggest 0-10 mph and 0-20 mph times. I think most can hit that. Anything more than that is great, but how about those as standard.

I think this could be valuable to put some numbers together to study. Any thoughts? E.

Sorry for nincompooping, but I thought this was the discussion thread and you were going to start another thread for the numbers.

 

[tostino]

Sorry for nincompooping, but I thought this was the discussion thread and you were going to start another thread for the numbers.

I thought the same thing. And when my bike is on the road again I will be happy to provide some numbers.

 

[gogo]

I'd like to resurrect this thread as a way of comparing setups without having to race each other. The idea is to put a card in your spokes, record it, analyze it on a computer sound app to get your data points, and then use the weight to derive a power curve. This should work, no?

 

[John in CR]

I'd like to resurrect this thread as a way of comparing setups without having to race each other. The idea is to put a card in your spokes, record it, analyze it on a computer sound app to get your data points, and then use the weight to derive a power curve. This should work, no?

gogo,

Are you volunteering to do the analysis? What about pedaling? On my moderate power rig, pedal assist for the 10 strokes or so that I can keep up makes a pretty significant difference in takeoff. Don't forget to factor in weight, because that's half of the equation. My daughter seemed to double my acceleration with same motor and voltage, about 1/2 the current, but a 20% larger wheel. That's because she weighs 140lbs less.

FWIW, racing sounds more like fun, and we can include the card thing too, along with video and gps data. To be sure recording speed isn't distorted, have music playing during the run, so the timing can't be manipulated, or it will be obvious in the sound of the music. We make our runs in whatever part of the world, send the data to you for tabulating.

 

[gogo]

I'd like to resurrect this thread as a way of comparing setups without having to race each other. The idea is to put a card in your spokes, record it, analyze it on a computer sound app to get your data points, and then use the weight to derive a power curve. This should work, no?

gogo,

Are you volunteering to do the analysis? On my own stuff, yes. What about pedaling? NO pedaling. On my moderate power rig, pedal assist for the 10 strokes or so that I can keep up makes a pretty significant difference in takeoff. Don't forget to factor in weight, because that's half of the equation. My daughter seemed to double my acceleration with same motor and voltage, about 1/2 the current, but a 20% larger wheel. That's because she weighs 140lbs less.

FWIW, racing sounds more like fun, and we can include the card thing too, along with video and gps data. To be sure recording speed isn't distorted, have music playing during the run, so the timing can't be manipulated, or it will be obvious in the sound of the music. We make our runs in whatever part of the world, send the data to you for tabulating. The idea is that the methods are detailed for everyone to use. If five guys get similar results with similar setups and the sixth guy deviates, you just ignore the cheater. I'm not suggesting this would be suitable for betting.

 

[REdiculous]

Sounds fun but maybe hard for everyone to do accurately.

Could you get close enough if you had (say) 4 checkpoints and timed a mile run? I could probably rustle up enough people and stop watches. Add an air horn and a flat mile?..

If that won't work, is there something better than cards? later