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I own a 2020 Cube Nuroad Race FE bike.

Do you perhaps know what model of hub dynamo this bike has or at least if it's AC or DC? I can't figure it out since there are no markings on it.

Here are a few images of the hub dynamo in question: https://imgur.com/a/AJVfrgX

3 Answers 3

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The standard output of hub dynamos is 6V A.C. and usually 3W, though smaller current outputs are available.

I think it is unlikely that your hub deviates from this well established standard, else it would be incompatible with almost all lights and charging accessories. Of course, as original equipment, the best place to ask the question is your CUBE dealer or the CUBE helpdesk.

You could also hook up the output to an oscilloscope and see what you get out of it. You should expect a sine wave (from an unloaded SP dynohub) or something a bit more triangular maybe. As Chris H demonstrates, the output is 12-15V peak-peak AC with frequency apparently dependant on wheel speed and the design of the hub.

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    The output from actual hub dynamos is more like sharp alternating spikes, with roughly 0.5A maximum current and maximum voltage somewhere way above 6V if the load has higher resistance than 12 ohms.
    – ojs
    May 23 at 13:07
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    @gschenk the spikes go both ways (i.e. it's AC, but not sinusoidal) so you need a bridge rectifier. Then the cheapest dynamo lights flicker, but better ones have enough of a capacitor to smooth that out. Standlight supercapacitor circuits re more complex (though I keep meaning to try building a basic one as I have a spare supercap and a flickering cheap light).
    – Chris H
    May 23 at 13:30
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    You could also hook up the output to an oscilloscope and see what you get out of it. I have in the past, and you don't. I'll see if I can get a picture
    – Chris H
    May 23 at 13:32
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    @ChrisH I'd like to know that: bicycles.stackexchange.com/questions/84024/…
    – gschenk
    May 23 at 13:38
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    @ojs I've now added some scope traces at gschenk's linked question
    – Chris H
    May 23 at 14:29
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According to the bike's data sheet the bike ships a Supernova E3 Pure 3 front light. It is specced for 6 V (AC) 3 W. This is a datum that indirectly supports JoeK's conjecture the hub provides these specs.

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It looks like it is a Kasai FS with branding removed. Kasai FS hub Details can be found on the manufacturers website: https://www.kasai-tech.com/fs-dynacoil-disc---ta.html

Excerpt from data sheet:

6v / 3W

Fits 6-bolt rotor or Centerlock rotor

15mm Thru-axle

OLD: 100mm

Flange-Flange:​​ 50mm

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