head and running light on a 12 volt system

[CroMagnum]

As I said before the European market is littered with very good LED lights for dynamo power, from the cheap "be seen" ones to €100+ instant daytime devices, and you can get them anywhere from the internet. How to hook up a rechargeable battery is also well understood, posted that circuit in here for everyone. Don't overthink it.

I'm so glad the Your-O-Pein's have it all figured out. Of course, your schematic won't work for grounded alternators or dynamos that already have rectifiers. A few wraps of electrical tape? What could go wrong with that? But hey, thanks for straightening us out. You're really adding a lot to the conversation. I feel so much more enlightened now.

 

[KB_UK]

I'm so glad the Your-O-Pein's have it all figured out. Of course, your schematic won't work for grounded alternators or dynamos that already have rectifiers.

Yes it does.

That's connected one way. Here's the other.

The other alternative is to just exclude the now-unnecessary rectifier from the circuit. You can just do that. It's four diodes. Just leave them out.

Look ma. no rectifier:

I'm puzzled why you're sceptical about wrapping two or three turns of electrical tape on your bike's fork blade before you clamp on the dynamo's mounting bracket there. What about that strikes you as difficult?

 

[CroMagnum]

Yes it does.

That's connected one way. Here's the other.

The other alternative is to just exclude the now-unnecessary rectifier from the circuit. You can just do that. It's four diodes. Just leave them out.

Look ma. no rectifier:

You conveniently left out the rectifier that would have one leg shorted to ground.

What I take issue with is your dismissive attitude. On one hand you're posting a schematic that you expect people to build from scratch. Maybe you and I could do it, but the vast majority of people here probably could not. So you really haven't posted any useful information. The only purpose it serves is to stroke your own ego. And the most important part of your schematic, the regulator, is just a black block. Plus it's in the wrong position before the rectifier. Again, not useful.

Then you immediately flip-flop into "You're dummies for building it - just buy it!" mode with:

As I said before the European market is littered with very good LED lights for dynamo power, from the cheap "be seen" ones to €100+ instant daytime devices, and you can get them anywhere from the internet. How to hook up a rechargeable battery is also well understood, posted that circuit in here for everyone. Don't overthink it.

First of all, most of us aren't in Europe. Second, you buy it from "the internet." Yeah, that really narrows it down. Again, a condescending post, completely uncontaminated by any useful information.

This is why when I post some advice it's geared toward the reader who may not be another Nikola Tesla but can probably understand and follow instructions if they're clear and complete. Something like "buy this part and this link and hook up the wires this way and your battery will charge." That's useful information that most people here can use.

I'm puzzled why you're sceptical about wrapping two or three turns of electrical tape on your bike's fork blade before you clamp on the dynamo's mounting bracket there. What about that strikes you as difficult?

Clamping over electrical tape for insulation is totally Mickey Mouse. Seriously, you're really going to depend on that? When that clamp bites through the tape on your AC dynamo, your precious circuit you posted is going to go up in smoke so fast you'd think it's made by Lucas.

So if you have some useful information to share with everyone, I look forward to it. But so far I'm a little disappointed.

 

[KB_UK]

You conveniently left out the rectifier that would have one leg shorted to ground.

No I didn't, because there is no short to ground - I've said twice now that you prevent any shorts to ground by isolating the AC side right at the dynamo's mounting bracket, by wrapping the fork in electrical tape before you put it on, and running a second AC phase wire right from the bolt. Now I've said it a third time.

What I take issue with is your dismissive attitude. On one hand you're posting a schematic that you expect people to build from scratch. Maybe you and I could do it, but the vast majority of people here probably could not. So you really haven't posted any useful information. The only purpose it serves is to stroke your own ego.

The question is how to hook up a battery to dynamo lights, I've shown so. If the reader can't follow the diagram, they can ask for help. Minor technical aptitude is generally expected on a forum about building custom mopeds.

And the most important part of your schematic, the regulator, is just a black block. Plus it's in the wrong position before the rectifier. Again, not useful.

I already described the regulator. It's a two-way (Transient Voltage Suppression, TVS) diode rated just above nominal power of what it's protecting. In the case of a 6V Dynamo you'd want 7V. 12V, you'd want 13V or so. The way it works is by shunting excess voltage to the other AC phase rather than allowing it further up into the circuit where it can cause damage.

And no it's not in the wrong position. When you're rectifying low voltages you're going to need diodes in your rectifier which have a low voltage drop - the downside is the maximum voltage they can handle is going to be correspondingly lower.

(In this circuit we're looking at normal voltages of either 6 or 12 volts, making 1N5817 a good diode to build a bridge rectifier from because of it's voltage drop of only 0.4V. It's maximum is 20V, and so off that 12V dynamo it's very much at risk of getting fried)

For this reason you need your overvoltage protection BEFORE the rectifier, not after. Otherwise your bridge rectifier will blow up.

[

Then you immediately flip-flop into "You're dummies for building it - just buy it!" mode with:

First of all, most of us aren't in Europe. Second, you buy it from "the internet." Yeah, that really narrows it down. Again, a condescending post, completely uncontaminated by any useful information.

The circuit is to add batteries between the dynamo and a lamp. You need to build this part. The lamps already exist, you can just buy them, and since you're not in the countries they're commonly sold, you'll use the internet for that. I linked the website of a popular manufacturer of these kinds of lamps.

The problem isn't a lack of "useful information". The problem is the void between your ears.

This is why when I post some advice it's geared toward the reader who may not be another Nikola Tesla but can probably understand and follow instructions if they're clear and complete. Something like "buy this part and this link and hook up the wires this way and your battery will charge." That's useful information that most people here can use.

I provided a diagram and even explained it to you when you misunderstood. You can just ask.

Hell, first post I made on the subject, I even included a picture of the commercial product the circuit is a copy of, the Sturmey-Archer DBU. It's very old and out of production but if you're absolutely insistent on buying instead of building, you can track one down and use it.

Clamping over electrical tape for insulation is totally Mickey Mouse. Seriously, you're really going to depend on that? When that clamp bites through the tape on your AC dynamo, your precious circuit you posted is going to go up in smoke so fast you'd think it's made by Lucas.

Yeah, I do depend on that. Electrical tape is an electrical insulator. That's it's job. It's very tough, waterproof, made of PVC. You can absolutely use it in this manner, I know because I've done it. All you do is scream about how basic electronics "won't work" even though you don't understand them.

You're like a kindergartener, proud of the fact that you can count to ten, and angry that someone is telling you there's more numbers. Drink a juice box and take a nap, but don't pretend you know more than the teacher. You've neither practical experience or theoretical knowledge of this subject, and every time you make a proclamation about what "won't work" or ignore something already written here, you make a fool of yourself.

 

[CroMagnum]

Are you done having your little temper tantrum yet?

Your little TVS diodes are not regulators - they're just transient protection. Like a MOV. They'll soon blow out if you rely on them to clamp the output every single cycle. Of course, once you clamp the alternator's output then you lose more voltage through the rectifier and you're low. Much better and more efficient to rectify and filter it first and then regulate it down to what you need. Especially when purpose-built rectifier/regulators are already available for $4 retail. Why build some Mickey Mouse piece of junk instead?

And you and I will have to agree to disagree on electrical tape under the fork clamp. If that's your idea of good building practice then I have no respect for the stuff you build.

 

[KB_UK]

Are you done having your little temper tantrum yet?

You spat your dummy out over a circuit that you said wouldn't work with a dynamo if it had a built in rectifier. I pointed out that you were wrong and demonstrated why. Then you made another post, much longer this time, where you made several more angry, demonstrably wrong claims.

Some of them were you trying to talk authoritatively about electrical principles that you misunderstood. Others were just you not understanding prior posts because you didn't read them all the way through.

At any rate you're in no position to accuse others of having a tantrum. You got angry that you were wrong, and responded to it by getting angrier and being more wrong.

Your little TVS diodes are not regulators - they're just transient protection. Like a MOV. They'll soon blow out if you rely on them to clamp the output every single cycle.

The voltage of alternating current electricity is a sine wave. Transient protection for a transient rise above acceptable voltage is the job it was invented for.

If you buy an off the shelf bike dynamo regulator, what you get is a TVS diode in a little package with two ring terminals. I know because I bought one when I needed one, then unwrapped it to see what's in there:

https://www.sjscycles.co.uk/dynamos/reflectalite-regulator-xgen2-for-sturmey-archer-dynohub/

If you need Dynamo power regulated into a smooth, stable DC supply, there's other solutions. But that's beyond what we need for our purposes. The modern LED lamps handle that themselves, and nicad batteries don't care.

Of course, once you clamp the alternator's output then you lose more voltage through the rectifier and you're low.

You lose voltage though the rectifier no matter what you do. That's inherent to rectification, diodes have an immutable voltage drop.

Our little TVS Diode isn't going to effect this because they have very little leakage below the voltage that they turn on.

Much better and more efficient to rectify and filter it first and then regulate it down to what you need. Especially when purpose-built rectifier/regulators are already available for $4 retail. Why build some Mickey Mouse piece of junk instead?

No this isn't true either, you keep saying things that aren't true. If you want to regulate your voltage down after it's rectified, then you need your rectifying diodes to be capable of withstanding the current unregulated - the regulator will not protect them because it's not in place to do so. This means you need bigger diodes with a higher blocking voltage, which means you're also having to put up with a higher voltage drop.

Compare the following:

1N5817 - blocking voltage 20V - drop 0.45V
1N5818 - blocking voltage 30V - drop 0.55V
1N5818 - blocking voltage 40V - drop 0.60V

In a bridge rectifier there are two diodes active at any one time. So if we built it with 1N5818, the most efficient diode that can still survive being the wrong side of the TVS with the 12V dynamo if it overvolts, we're losing an extra 0.2V, compared to 1N5817 placed after the TVS.

That's about 3% power loss to do it your way, which isn't a disaster, but it's still both more slightly more expensive and slightly less efficient.

As for your $4 off the shelf regulator/rectifier unit, do you know what the voltage drop is going to be on that? I bet it's more.

And you and I will have to agree to disagree on electrical tape under the fork clamp. If that's your idea of good building practice then I have no respect for the stuff you build.

You've repeatedly shot your mouth about basic electronics and repeatedly been proven wrong, so I'm glad I don't have your respect. You don't have the reasoning skills to know how to assign respect correctly.

These lack of reasoning skills were demonstrated when you suggested cracking open and manually rewinding a dynamo, which can take hours, when the same result can be achieved with ten centimetres of black PVC electrical tape, which takes ten seconds.

 

[machanic]

Nice rant, I think you defended yourself well, but the proof is in the pudding, build it and find out. A point I didn't see (or missed) was that if the dynamo has one wire and the case or ground is the other conductor SO WHAT the bike frame is the other wire, one wire to the rectifier from the dyno the other the bike frame to rectifier ac input and the DC side only in isolated wire.

 

[KB_UK]

Already built one, working good and proper as the original designer intended all those years ago

You could get away with using the frame as the second AC wire on the rectifier but only if you're 100% sure your lamps aren't electrically connected to the frame. So all the cheap 1-wire lamps are out, so are a lot of two wire stuff with metal housings. The contact that touches the back of the bulb on most of them is just a strip of metal riveted to the case. I've got one where the contact is even attached right onto the mounting bolt, they just made a little slot in the case and shoved it through.

(That one's a real POS because if you move the light up and down the contact stays rigid bolted to the bike. Tilt too far down and the light goes off because it doesn't touch the bulb anymore. Too far up and it touches too hard and the bulb pops out)

You could insulate both lights from the frame instead of the dynamo but it's a lot more difficult because of how lamps attach, they're usually bolted on, the dynamo just clamps a tube.

 

[CroMagnum]

I'm looking at your pictures you posted and I don't see a motor on that bike. Do you even own an MB? Your circuit probably works good enough at pedal speeds of around 10 MPH. But what happens when you hit 20, 30, or 40 MPH? And that's what we're talking about here. This is a motorized bicycle forum in case you didn't notice.

Your parallel clipping scheme is going to have problems at 30 or 40 or 50 volts when the only current limit is the coil impedance. And I really hope those are big diodes capable of dissipating several watts continuously because they're probably going to blow. Also, clipping the output of an AC signal is called limiting, not regulating. At low output you may just clip some of the peaks off, and the RMS is going to be much less than the peak. But as the voltage rises with speed, the output starts looking more like a square wave, and while the peak will still be the same, the RMS will climb.

I still can't believe you're advocating the electrical tape around the fork leg as a reliable insulator. For years I've seen people on pedal bikes use tape just to try and protect the paint. And every time they've removed the clamp it's always chewed right through the tape and into the paint. Now you put this on an MB where the speed, jolts, and vibrations are orders of magnitude higher and your insulation scheme will not last very long.

You see, motorized bikes have problems and operating issues that don't occur to pedal bicycles. So before you start criticizing again why don't you bolt a china girl motor to that bike and see what happens at traffic speeds to the charging system. And also watch what happens to those cute metal fenders. I hope you're wearing a helmet when they go.

 

[KB_UK]

Oh my goodness, after being put through the wringer on every technical detail you've come back for more. Excellent, I can do this until the cows come home.

I'm looking at your pictures you posted and I don't see a motor on that bike. Do you even own an MB?

Yeah and It's been posted here before. Out of commission this winter as I'm in a different country, check my post history

Your circuit probably works good enough at pedal speeds of around 10 MPH. But what happens when you hit 20, 30, or 40 MPH? And that's what we're talking about here. This is a motorized bicycle forum in case you didn't notice.

Your parallel clipping scheme is going to have problems at 30 or 40 or 50 volts when the only current limit is the coil impedance. And I really hope those are big diodes capable of dissipating several watts continuously because they're probably going to blow. Also, clipping the output of an AC signal is called limiting, not regulating. At low output you may just clip some of the peaks off, and the RMS is going to be much less than the peak. But as the voltage rises with speed, the output starts looking more like a square wave, and while the peak will still be the same, the RMS will climb.

Okay this is really funny, just a few posts ago you didn't know how the circuit you hate works, embarrassing yourself over the age old mystery "Can diodes accept DC input?" - but now you're spitting out every technical word you can remember.

Underneath all of this bluster : "Your TVS diode needs to be rated for the load".

Very astute, Sherlock. What would we do without you?

I still can't believe you're advocating the electrical tape around the fork leg as a reliable insulator. For years I've seen people on pedal bikes use tape just to try and protect the paint. And every time they've removed the clamp it's always chewed right through the tape and into the paint. Now you put this on an MB where the speed, jolts, and vibrations are orders of magnitude higher and your insulation scheme will not last very long.

I advocate electrical tape around the fork leg because it works. Three turns is enough, four if you're paranoid - it features on my own motorized bike both on the dynamo and the pletcher rack, on my green Raleigh's rack and kickstand, and even on my black racing bike where I hose-clamped a second bottle cage on there. If you only do one turn then that's not going to be thick enough, which Is why I say do three or more.

Only problem I had with vibrations and the lighting was the dynamo's mounting bolt shaking loose. The electrical tape held up fine.

You see, motorized bikes have problems and operating issues that don't occur to pedal bicycles. So before you start criticising again why don't you bolt a china girl motor to that bike and see what happens at traffic speeds to the charging system. And also watch what happens to those cute metal fenders. I hope you're wearing a helmet when they go.

You're saying "don't criticise without trying!" when you've done nothing but criticise this lighting setup, and have never tried it, and that everyone who has tried it is successful.

The bike I posted in this thread is a Raleigh model 13 - Superbe. One of the things that made Raleighs expensive and unique was those "cute fenders" - their appearance comes from them being designed for strength. The ridges and peak add stiffness, the stays are U-shape steel tubes welded in place along the inside surface rather than bolted or riveted. This isn't a wallyworld toy, it cost 1/5th the average yearly wage, and people would take out loans just to get one. The design lifespan was "For ever", with the guarantee lasting until the owner either sold it on to someone else, or died.

Raleighs like this were always very popular motorised bikes. There was thousands of these with engines attached, Cyclemaster, REX, BSA winged-wheel, trojan mini motor, etc.

Raleigh even sold the ladies version with an engine of their own design for a few years, before the market moved towards real mopeds. Fender failures have never been a problem for it.

So the lighting circuit is proven and tested. So is the bike it's a part of, starting 72 years ago - people have been motorising them without a problem likely before you or I were born. Your reality denial makes you sound like the flat earth society, so I advise you to give up.