ADAC Big bike test by german auto union

[Daskino]

Hey all Just saw a post of the test made by ADAC and Stiftung Warentest.

many e-bikes fail in this test. Even kalkhoff has issues.


Good read see more here and table of the test results

http://www.adac.de/infotestrat/tests/fahrrad-zubehoer-sport/pedelec_2011/default.aspx?ComponentId=82768&SourcePageId=6729

http://www.presse.adac.de/Download.asp/DName=C%3A%5CDokumente+und+Einstellungen%5Cekoexbil%5CDesktop%5CAktuell%5CPedelec+Test%5CPedelecs+im+ADAC+Test%5F15.jpg/FilePath=%2Ftcmbinary%2FPedelecs%20im%20ADAC%20Test_15_tcm11-325198.jpg/ContentType=application%2Fx%2Dunknown/C%3A%5CDokumente+und+Einstellungen%5Cekoexbil%5CDesktop%5CAktuell%5CPedelec+Test%5CPedelecs+im+ADAC+Test%5F15%2Ejpg

Artikel in English

http://www1.adac.de/adactv/test_technik/pedelec-test_2011.asp?quer=adactv

28/07/2011

 

[10mph]

Thanks for the links, Daskino. I could not understand the test scoring.

What I found extremely interesting was the movie of the testing which you linked.

Here are two frames from the movie showing a motor on the seat post and driving the pedal shaft by means of of chain to a sprocket, which you can just see, on the crank shaft where the left pedal is normally mounted.

I have previously puzzled myself trying to work out an effective scheme of how to make a set up to test a Panasonic motor powered pedelec with a combination of pedal power and Panasonic motor assist. This set up is brilliant: easy to measure the power input on the left pedal, and then just measure the backwheel output on a rolling-road type of dynamometer.

 

[flecc]

I have to differ slightly, it is certainly interesting but inaccurate since the force rate is constant throughout the arc. A cyclists force rate is only at maximum when the crank length is at about 90 degrees to the leg, diminishing at a non-linear rate according to the crank distance above and below that.

 

[10mph]

I have to differ slightly, it is certainly interesting but inaccurate since the force rate is constant throughout the arc. A cyclists force rate is only at maximum when the crank length is at about 90 degrees to the leg, diminishing at a non-linear rate according to the crank distance above and below that.

That is a good point.

I get an impression that some variation is definitely present underr lighter pedal loads. However, when I climb a steep hill, I have noticed that the voltage drop at the battery terminals does not fluctuate but is very steady at typically 1.7 Volts drop. This indicates constant current from the battery not dependant on pedal position, even when my cadence drops at 5 or 6 mph.

Perhaps the controller's time constant alters according to the the amount of sustained power one is calling for. When it recognises that you are working hard it could increase the time constant to provide uniform power throughout 1 pedal rotation. When one slackens the demand level it could switch to a mode with a time constant that more closely follows the varying demand during one rotation of the pedals, thus giving good controllability and instant response to stopping pedalling.

This is rather speculative - but it would seem to be a sensible way of designing the system to provide maximum power when needed. Maybe we can do some tests to investigate the time response more closely.

 

[flecc]

I think that's probably true, since there is a subjective impression that is the case. The seatpost motor testing then would be more relevant to the somewhat fitter cyclist than the weaker/maybe older one.