Dynamo Lighting - fit and forget?

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Brucey
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Re: Dynamo Lighting - fit and forget?

Post by Brucey »

edocaster wrote:Having the overall switch in the front light control both lights is a requirement of German law.


presumably that is only for hub dynamos, since lamps for tyre drive dynamos have no such thing.

cheers
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Mick F
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Re: Dynamo Lighting - fit and forget?

Post by Mick F »

............. or battery lights.

Perhaps battery lighting isn't legal in Germany?
Mick F. Cornwall
PH
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Re: Dynamo Lighting - fit and forget?

Post by PH »

Mick F wrote:............. or battery lights.

Perhaps battery lighting isn't legal in Germany?

Unless it's changed in the last few years - In Germany dynamos are required on all cycles other than racing ones weighing less than 11kg and these can use battery lights which have to be carried if not fitted.
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Mick F
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Re: Dynamo Lighting - fit and forget?

Post by Mick F »

Visitors?
What happens if I was still in the RN and called in at a German port .............. been there twice in the past and both times with a bike. Bremen and Bremerhaven.

I took my Mercian with me on the my ships, and before that, my Raleigh Clubman, and before that my sit up and beg Raleigh Esquire. I've cycled in many many countries worldwide, and as far as I can remember, never had any lights at all. If I had needed them, they'd have been battery ones.

I know times have changed, but if I were to ride ashore now into the German town without any lights or maybe only battery lights, would I be breaking the law?
Mick F. Cornwall
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andrew_s
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Re: Dynamo Lighting - fit and forget?

Post by andrew_s »

Mick F wrote:Visitors?
I know times have changed, but if I were to ride ashore now into the German town without any lights or maybe only battery lights, would I be breaking the law?

There's a treaty (Vienna convention on road traffic, 1968) that says that, as a foreigner on a temporary visit, you only need to have the following, unless they aren't required by local law:
An effective brake
a white front light
a red rear light
a red rear reflector
a bell

It says nothing about the type/brightness of the lights, or when they need to be fitted

You probably were illegal - you should have had some lights fitted to the bike (Germany), and a bell (Netherlands, at least)
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Mick F
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Re: Dynamo Lighting - fit and forget?

Post by Mick F »

Thanks!
Breaking the law eh?
Nobody told me. :oops:

Cycled Germany in early 1990's and Holland and Belgium and France too in the late 1980s.

Foreign countries (In no particular order)
Gibraltar, including to the Top of the Rock, and into Spain.
Naples, including up Vesuvius to the Seismic Observatory.
Corfu
Haifa, Israel
Bahrain
Mombassa, Kenya
Karachi, Pakistan
Columbo, Sri Lanka
Malaysia
Thailand
Bermuda
Singapore
Port Moresby, Papua New Guinea
Jakarta, Indonesia
Nassau, Bahamas
Bunbury, Western Australia
Adelaide
Sydney, including into the Blue Mountains
Hobart to Port Arthur, Tasmania
Caen, and the Normandy Coast
Bremen, Germany
Bremerhaven, Germany
Antwerp
Amsterdam
Copenhagen

USA:
500 miles from Niagara Falls, Canada to Portsmouth, New Hampshire. Taking in New York State, Vermont and Massachusetts.
Florida, Cape Canaveral and Jacksonville.
Wilmington, North Carolina
Manhattan
Mick F. Cornwall
De Sisti
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Re: Dynamo Lighting - fit and forget?

Post by De Sisti »

Mick F wrote:Thanks!
Breaking the law eh?
Nobody told me. :oops:

Cycled Germany in early 1990's and Holland and Belgium and France too in the late 1980s.

Foreign countries (In no particular order)
Gibraltar, including to the Top of the Rock, and into Spain.
Naples, including up Vesuvius to the Seismic Observatory.
Corfu
Haifa, Israel
Bahrain
Mombassa, Kenya
Karachi, Pakistan
Columbo, Sri Lanka
Malaysia
Thailand
Bermuda
Singapore
Port Moresby, Papua New Guinea
Jakarta, Indonesia
Nassau, Bahamas
Bunbury, Western Australia
Adelaide
Sydney, including into the Blue Mountains
Hobart to Port Arthur, Tasmania
Caen, and the Normandy Coast
Bremen, Germany
Bremerhaven, Germany
Antwerp
Amsterdam
Copenhagen

USA:
500 miles from Niagara Falls, Canada to Portsmouth, New Hampshire. Taking in New York State, Vermont and Massachusetts.
Florida, Cape Canaveral and Jacksonville.
Wilmington, North Carolina
Manhattan

You were in the Navy for how Long, and only visited a handful of countries? :shock:
StephenW
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Re: Dynamo Lighting - fit and forget?

Post by StephenW »

Unless it's changed in the last few years - In Germany dynamos are required on all cycles other than racing ones weighing less than 11kg and these can use battery lights which have to be carried if not fitted


The law has changed! I remember hearing it on the local radio station when I was visiting the island of Sylt. I think that was in 2013.

Battery lights are now OK.

It's interesting that this change in the law was considered newsworthy on a local radio station!
robc02
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Re: Dynamo Lighting - fit and forget?

Post by robc02 »

ConRAD wrote:
in the front light there's a built-in AC "clipping" device acting as overvoltage protection (OVP), most of the times nothing more than a double zener, that's it.


MickF wrote:
My original thought was that the front light somehow exports the power aft and each make of front light would be different in this regard perhaps.

Maybe my original thought is correct and they aren't in parallel?


Out of curiosity I took apart a spare B&M Cyo and found a transient suppressor connected across the supply from the hub. It is the first component in the circuit - before the switch. It is marked MXJ so seems to be described in this data sheet:

http://www.s-manuals.com/pdf/datasheet/p/6/p6smb6.8-p6smb200a_tsc.pdf

as a P6SMB100A with a breakdown voltage between 95 and 100V. So it is to to prevent large overvoltages, such as switching spikes, rather than as part of the LED supply regulation. This makes sense, as if it were say a 7V device it would conduct almost all of the time the light is switched off, sinking the current the light would otherwise draw, therefore resulting in as much drag as if the light was left on. I know that a fast spinning open circuit hub generator can produce many tens of volts, but can it reach 100V? Perhaps someone living near a long steep hill can strap a voltmeter their handlebars to try it out!

I checked for continuity between the supply terminal and the output to the rear light. There was continuity on one conductor, but not the other, so the front and rear are not internally hard wired in parallel. (My lamp has a photocell built in, but has three switch positions - off, photocell (I think they call it "Senso") and on. I did all my tests in the "on" position.)

I then connected a B&M Seculite to the rear light terminals and a variable AC (50Hz) power supply to the main input terminals. Voltmeters were connected across supply and rear light terminals and the supply was varied, at approx. 0.5V intervals, from 1.5 to 8V. Here are the results:

Main Supply (V) 1.50, 2.03, 2.50, 3.01, 3.52, 4.09, 4.52, 5.01, 5.53, 6.01, 6.53, 7.01, 7.36, 8.00
Rear Supply (V) 0.32, 0.43, 2.22, 2.96, 3.50, 4.04, 4.48, 4.97, 5.47, 5.92, 6.42, 6.83, 7.32, 7.70

The meters were checked by connecting them in parallel and were typically within 0.01V of each other.
As can be seen the rear light supply was consistently a few hundredths of a volt lower than that of the front, but there was no obvious limiting of the supply to the rear over the range tested. I didn't want to raise the voltage further for fear of damaging two perfectly serviceable lights!

So it seems that, to all intents and purposes and in this model of light, the front and rear lights are connected in parallel, albeit by electronic means.

I would have liked to have investigated the circuit operation further, but to trace the tracks on the PCB some of the components would have to be removed. Likewise to "buzz them out" as some of the connections are not accessible from above.
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Mick F
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Re: Dynamo Lighting - fit and forget?

Post by Mick F »

Excellent!
Thanks for doing that. Great bit of info.
Mick F. Cornwall
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Gattonero
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Re: Dynamo Lighting - fit and forget?

Post by Gattonero »

PH wrote:It's all interesting stuff, but I like that it just all works, I turn the switch and the lights come on... hurray!!!


Same here: fit and forget 8)
It is by riding a bicycle that you learn the contours of a country best,
since you have to sweat up the hills and coast down them.
Thus you remember them as they actually are...
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ConRAD
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Re: Dynamo Lighting - fit and forget?

Post by ConRAD »

robc02 wrote: ... ... it is marked MXJ ... P6SMB100A with a breakdown voltage between 95 and 100V. So it is to prevent large overvoltages, such as switching spikes, rather than as part of the LED supply regulation. This makes sense, as if it were say a 7V device it would conduct almost all of the time the light is switched off, sinking the current the light would otherwise draw, therefore resulting in as much drag as if the light was left on. I know that a fast spinning open circuit hub generator can produce many tens of volts, but can it reach 100V? Perhaps someone living near a long steep hill can strap a voltmeter their handlebars to try it out! ....

Yes, the MXJ-P6SMB100A with a Vbr=95-105V appears to be exactly as you say, i.e. a Transient Voltage Suppressor suitable to prevent large/very short duration and NOT repetitive overvoltages such as switching spikes, say in the order of micro seconds rather than milliseconds. Being wired before the switch it will always be present but idle so far till a spike arrives !!
The light voltage regulation conceived to limit the voltage to something around 6.7-7.1V and implemented to achieve the StVZo "K" approval/marking is a different story and if you investigate further you'll see that is placed after the switch and, as a consequence, till the switch is off it will make absolutely NOTHING!
PS: at 100 km/h a hub dynamo, at no-load, will easily arrive up to 100 V !!

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edocaster
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Re: Dynamo Lighting - fit and forget?

Post by edocaster »

My Axa Pico 30 is finally playing up, after three years. It flickers and cuts out at speed now, resetting when stopped. Sounds almost exactly like a resettable overvoltage crowbar. Obviously it shouldn't be happening if the light is enough to saturate the 500mA from the dynamo. I'm not sure what has changed, but these are small lights with surface mount components, and probably switching power supplies. Lots of things to blow up. I'll probably go for a b&m eyc or cyo now.
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meic
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Re: Dynamo Lighting - fit and forget?

Post by meic »

Brucey wrote:toplight line plus works from AC without issue (of course). The + terminal designation is irrelevant for AC use, and such markings are often used on AC dynamo systems to distinguish between ground and live connections on systems with earth returns. The toplight line plus has no earth return and can wired up how you like (presumably even with a DC input).

BTW B&M rear lights do vary in their ability to run directly from a generator (i.e. without a front light). In some models the overvoltage protection is 'temporary' and in others it is better than that. Best to read the small print.

cheers

By coincidence on the day you wrote this I was setting off on a tour running a B&M mini rear permanently wired to the dynamo but the front only on when needed. It lasted a day before failing.
The website said it is overload protected, I didnt see any further small print.
Yma o Hyd
edocaster
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Re: Dynamo Lighting - fit and forget?

Post by edocaster »

Just a heads up, but Amazon may have good prices for:

B&M 'Eyc T': https://www.amazon.co.uk/Busch-Müller-L ... IUC74?th=1 - £20

and

B&M 'Cyo Premium Senso': https://www.amazon.co.uk/Busch-Müller-L ... s_sp_4_vtp - £29

The descriptions are confusing, but the model numbers check out. I've ordered the latter (there are only 4 left, currently).
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