Battery versus Dynamo

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Urticaria
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Re: Battery versus Dynamo

Post by Urticaria »

mjr wrote:Secondly, a wire with a stripe is usually an earth wire. It seems obvious once you know, but it would have been nice if the Pico's packaging had mentioned this.

Be careful with a rule like this. My front dynamo light's connection to the rear is the opposite, and it says so on the box. Also, many of the cylindrical DC plugs that come attached to PSUs have the centre pin +ve, and that is connected to the wire with the white stripe.
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mjr
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Re: Battery versus Dynamo

Post by mjr »

Oh great! Thanks for the warning.

Today the plug rattled out of the bottom of the pico, leaving me with no lights until I fixed it. It's a rectangular four pin plug that pushes up into the bottom of the light. Any suggestions on how to secure it better? Those cobbles won't be relaid quickly :-/

To be fair, I've had battery lamps flop forwards on surfaces that bad, so I'm not blaming the dynamo system for this!
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
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[XAP]Bob
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Re: Battery versus Dynamo

Post by [XAP]Bob »

A dab of "hot glue" or bathroom sealant?
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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mjr
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Re: Battery versus Dynamo

Post by mjr »

Right - I've reattached the wires (I detached them to bodge a fix yesterday) and put a dab of sealant either side of the plug. That'll be fun to remove if the headlight ever fails and has to be returned under warranty. Thanks again!
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.
Brucey
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Re: Battery versus Dynamo

Post by Brucey »

I'm not familiar with the plug in question but in many cases plugs come out because of the weight/pull of the wires, rather than the weight of the plug per se.

So, if you don't have it already, I'd also suggest a little 'strain relief' i.e. tethering the wires nearby so that they pull and flex etc near the tether, and there is less chance of a pull on the wires dislodging the plug.

Also I guess these instructions;

http://www.axa-stenman.com/fileadmin/axa_bc/content/images/Verlichting/Handleidingen/mh37560_pico30_.pdf

don't quite look like your light then, either?

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
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mjr
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Re: Battery versus Dynamo

Post by mjr »

I've added a new cable tie near the top of the fork to try to preserve the slack on the plug. That's my light but not the instruction card I got attached to mine. That one looks improved (it says which wire is earth!) but it doesn't show clearly that the connection leads (two to back light, two to dynamo) come ready-wired into a four-pin plug that is inserted into the bottom of the light body.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.
RJC
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Re: Battery versus Dynamo

Post by RJC »

Update on the Union 4268 LED front light (see p.10 of this thread):
After about 6 months of use I started to have a problem with intermittent rear light connection.
It turned out that one of the metal tabs used for the rear light connection inside the front light was no longer making
a good contact to the circuit board. I guess movements of the wires to the rear light had cracked the solder joint.
Reheating the joint didn't solve the problem so I ran a short wire from the tab to another point
on the same pcb trace. I've also cable tied the wire to the rear light to the front light support bracket
to avoid stressing the metal tags in future.

I recently bought one of the Philips 60lux dynamo front light before they possibly disappear.
I did some measurements with a DC supply:
5.5V 64mA
6.0V 193mA
6.5V 406mA
7.0V 677mA
7.2V 790mA
7.3V 850mA (I couldn't really get beyond this with the supply I was using)
I expect there will be some variation between lights. Some numbers
I saw previously on a German forum had lower currents for the same voltages.
Unlike some dynamo lights reversing the polarity didn't seem to matter.

The light started to dim below 6.5V but above this the increase in brightness
wasn't immediately obvious. It was still brighter at 6V 0.2A compared to a 6V 0.4A halogen lamp,
so currently I am thinking of using this light to upgrade a 6V battery system from halogen
with a voltage booster circuit for when I need full power.
There is a pedelec version of the light which can run from 6-48V but this is more expensive and
will always run at full power.
edocaster
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Re: Battery versus Dynamo

Post by edocaster »

Interesting. Are you sure you are supposed to use a DC voltage source on the light? I know that some dynamo lights allow it, but it's not universal. I know that most DIY lights rely on the dynamo to be current-limited to 500mA or so.

Was it brighter than on dynamo when it got to 800mA or so?
Cavemud
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Re: Battery versus Dynamo

Post by Cavemud »

Haven't read the whole thread so apologies if this has been mentioned already:

1) Have you looked at the supernova e3 triple? Too bright to be road legal apparently. How bright to you want?
2) I have the e3 triple on a cat eye style quick release bar mount so I can chain my bike in the city with light removed.
3) the ability to charge phones etc from a dynamo on tour is great, and can be easily bought (expensive) or built for less than a tenner with parts readily available from Maplin.

Good luck.
RJC
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Re: Battery versus Dynamo

Post by RJC »

edocaster wrote:Interesting. Are you sure you are supposed to use a DC voltage source on the light? I know that some dynamo lights allow it, but it's not universal. I know that most DIY lights rely on the dynamo to be current-limited to 500mA or so.

Was it brighter than on dynamo when it got to 800mA or so?


I couldn't do a realistic comparison of dynamo mode & DC 800mA since one involves riding around and the other case was
with the light hooked up to a mains power supply shining against a wall.
I tried with a battery slightly above 6V last night. This gave ~300mA and I thought it seemed slightly brighter in dynamo mode
but couldn't swear to it, since there was 5 minutes of fiddling to switch between modes.
When running in boosted mode I will be cautious about taking it much over 0.5A especially if it doesn't give much
extra light for the battery drain. The LEDs should have reasonable cooling since they are in contact with the metal case.
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[XAP]Bob
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Re: Battery versus Dynamo

Post by [XAP]Bob »

Cavemud wrote:Haven't read the whole thread so apologies if this has been mentioned already:

1) Have you looked at the supernova e3 triple? Too bright to be road legal apparently. How bright to you want?
2) I have the e3 triple on a cat eye style quick release bar mount so I can chain my bike in the city with light removed.
3) the ability to charge phones etc from a dynamo on tour is great, and can be easily bought (expensive) or built for less than a tenner with parts readily available from Maplin.

Good luck.


Too bright to be legal isn't possible in this country - too dazzling is questionable given how appalling most of the German DLR implementations are in that regard...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
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