On Mon, 29 Mar 2021 12:23:28 +0200, Sepp Ruf
wrote:
Frank Krygowski wrote:
But again, thanks. (I'm hoping that on the bench, powering this with a
6VDC battery should be as valid as powering it with a dynamo.)
Not the AC-Eyc, RTFM.
That was my suggestion. I assumed that anything with a bridge
rectifier on the AC input would also run on DC.
Nothing in the data sheet:
https://www.bumm.de/en/products/dynamo-scheinwerfer/produkt/160rtsndi%20.html
However, the instructions say otherwise:
https://www.bumm.de/files/Produkte/LUMOTEC%20Eyc_Avy_IQ-XS.PDF
The headlight can only be powered by a dynamo (AC). Connection
to a DC power source (battery) is not possible.
I don't have a schematic or headlight to dissect. I wonder what
they're doing to prevent DC operation.
There is a 6 to 42VDC Eyc version:
https://curbsidecycle.com/products/busch-muller-lumotec-eyc-dc-front-light-e-bike
which probably has a different DC-DC buck converter. I couldn't find
this DC version on the B&M site, but did find this:
https://www.bumm.de/en/products/e-bike-beleuchtung.html?info=1
In Germany before 2014, e-bikes had to have a regular
bicycle dynamo powering the light system. Such a dynamo
supplies 6 VC AC. If your e-bike is equipped with a
dynamo, it is not suitable for use with an e-bike headlight.
All our dynamo-powered headlights may be used in this case.
I'm suspicious that this is a safety measure inspired by users
connecting the AC dynamo version of the headlight to an eBike with a
12, 26, or 48 VDC battery and destroying the headlight. Nobody makes
a 6VDC eBike making the risk quite real. However, to be safe and in
case I missed something, I won't suggest that Frank plug his Eyc into
a 6VDC battery.
Peter White Cycles nothing about battery power in the Eyc section at:
https://www.peterwhitecycles.com/b&m-hl.php
but does have a note about running the IQ-X on 5VDC from USB power.
We have recently discovered, (April 19, 2017) that the
IQ-X headlight and the Busch & Müller USB-WERK charger
are not compatible. When the cache battery in the
USB-WERK is charging, the IQ-X beam becomes quite dim.
While riding, this can happen for about two seconds,
every thirty seconds or so, and so causes a dangerous
situation, since the rider will briefly not be able to
see the road ahead. If you have the USB-WERK and plan
to use the IQ-X headlight, you should be prepared to
unplug the USB-WERK at night. I recommend using the
Lumotec IQ CYO Premium T Senso Plus or the new IQ-XS
with the USB-WERK, since they are unaffected by this.
My guess(tm) is the IQ-X lights require the peak AC voltage
(6VAC * 1.414 = 8.5V) to operate at full brightness or the charging
current causes a voltage drop to below the IQ-X operating point. The
Eyc might have a similar problem.
But how about a new lamp and some real circuit?
http://tandem-fahren.de/Mitglieder/Framstag/LED/Wollmilchsau/
Google translate did a good job of translating the German into
English. I can't resist looking at the circuit but have only 15
minutes.
Looks like you may have confirmed my low voltage theory:
The Busch + Müller IQ-X E that was evaluated first turned
out to be unusable in the dynamo emergency mode:
up to 20 km / h it remains quite dark and above it
flickers at approx. 1 Hz.
Congrats, you created a relaxation oscillator.
- I don't see an over or under voltage protection (battery management
system) for the LiIon cells on the schematic. However, there's one in
the photo of the red 18650 cells and mentioned in the text. However,
the BMS mentioned in the text is not available in 2S.
- If the red colored 18650 cells in the photo are from "GTL", I have a
few and they are junk. The Samsung cells are much better.
- I don't see the usual resistive divider and timing capacitors on the
555 chip (U2).
- Do you have a LUX meter? If so, I have a lumens measuring
experiment I would like to have you try. Details later.
Thanks, good luck, and I'll be back with more tomorrow.
--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558