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#1336393 - 05/11/18 10:31 AM USB Chargers
ConRAD
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First of all thanks to Fahrradzukunft [https://fahrradzukunft.de/] for having published and so far shared all the below charts and information.
Said that, due to my very poor German knowledge, I’d appreciate if someone could help me in German to English translation and possibly confirm my “Highlights&Conclusions”
Thank you in advance.



LEGEND
- Ladesleistung in die Akku-zellen = battery charging power [W]
- Fahrgeschwindigkeit = speed [km/h], all data based on SON28 assembled on a 28” wheel
HIGHLIGHTS&CONCLUSIONS: with some models at 20 km/h it seems to be possible to have up to 5.5W charging power to the internal buffer battery


LEGEND
- Max Dauerhafte USB-Leistung = max permanent power at USB output [W]
- Fahrgeschwindigkeit = speed [km/h], all data based on SON28 assembled on a 28” wheel
HIGHLIGHTS&CONCLUSIONS: with some models at 20 km/h it seems to be possible to have up to 5.0W permanent power at USB output


LEGEND
- Wirkungsgrad Akku zu USB = efficiency power_battery/power_USB [%]
- Entnahmeleistung am - USB-Anschluss = power on USB output [W]
HIGHLIGHTS&CONCLUSIONS: with some models at 3W USB output it seems to be possible to reach up to 84% efficiency (QUESTION: is efficiency to be intended as overall efficiency, i.e. dynamo to USB output, or just internal buffer battery to output ???)


LEGEND
- Fahrgeschwindigkeit = speed [km/h], all data based on SON28 assembled on a 28” wheel
- Electrische Leistung Dynamo = dynamo electrical power [W]
HIGHLIGHTS&CONCLUSIONS: with some models at 20 km/h it seems to be possible to have up to 6.5W transferred power from the dynamo to the charger
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#1345968 - 07/07/18 09:16 AM Re: USB Chargers [Re: ConRAD]
maram
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Originally Posted By: ConRAD
(QUESTION: is efficiency to be intended as overall efficiency, i.e. dynamo to USB output, or just internal buffer battery to output ???)

If you look on Steckdose unterwegs (http://fz.0x0c.de/11/steckdose-unterwegs/) you will see that this is the efficiency from the output of the battery battery to USB, that is, how hot is the voltage converter becoming...
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#1346221 - 07/09/18 08:03 AM Re: USB Chargers [Re: maram]
ConRAD
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Very clear, thank you.
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#1387616 - 05/24/19 09:37 AM Re: USB Chargers [Re: ConRAD]
ConRAD
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With reference to "e-werk" and looking at the below specific plot, I've a question:

QUESTION: is the e-werk output power referred to a specific e-werk output voltage, i.e. is the output power at 20km/h allover the same from 2.8V to 13.3V?

The reason I ask it is because, just to make an example, at 5.6V I get more then 3W.

Thank you for any reply.

According to the Forum Rules, only own pictures, texts, etc. may be shown in posts. Therefore, I had to give a link for this picture (fortunately, I know from where it was taken).

Figure taken from "Fahrradzukunft"

Edited by Keine Ahnung (05/24/19 09:44 AM)
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#1413173 - 01/25/20 01:52 AM Re: USB Chargers [Re: ConRAD]
derSammy
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Nobody willing to reply to you? What a pity!

Quote:

HIGHLIGHTS&CONCLUSIONS: with some models at 20 km/h it seems to be possible to have up to 5.5W charging power to the internal buffer battery

Correct, Forumslader V5 does so, Dynamo Harvester almost.

The second graph shows USB-output power. I assume that E-Werk is adjusted to 5V, anything else makes no sense in this comparison.

Question for the third plot was answered (its only efficiency energy-flow batteries to USB-output).

Last question: Yes, but note this is merely an observation how much energy is taken from the dynamo, but not how much energy is indeed stored to batteries or transfered to USB-output. The improved DynamoHavester e.g. takes more energy from the dynamo @20km/h than the Forumslader, but stores less energy to the batteries. I.e. it is less efficient.
Komm wir grillen Opa. Es gibt Koch und Suppenfleisch!
Satzzeichen können Leben retten.
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#1413174 - 01/25/20 02:00 AM Re: USB Chargers [Re: ConRAD]
derSammy
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Originally Posted By: ConRAD

QUESTION: is the e-werk output power referred to a specific e-werk output voltage, i.e. is the output power at 20km/h allover the same from 2.8V to 13.3V?

The reason I ask it is because, just to make an example, at 5.6V I get more then 3W.

I could not follow your calculation. The plot tells you the power in dependence of the velocity. As I told, I assume it was adjusted to 5V, but at least with respect to minor adjustments I expect a higher current I, provided the voltage U is dropped and vise versa (such that U*I remains at the level given in the plot).
Komm wir grillen Opa. Es gibt Koch und Suppenfleisch!
Satzzeichen können Leben retten.
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#1415239 - 02/10/20 03:15 PM Re: USB Chargers [Re: derSammy]
ConRAD
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Originally Posted By: derSammy
... I could not follow your calculation ...

Don't worry, it isn't so importan so far.
I think there may be some confusion on the sequence of the four plots above.
Indeed the 1st/3rd/4th are referred to USB-werk, the 2nd is referred to the "more classic" e-werk !!
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