Abate Holding Your Breath...Thompson's Design

Of course they do. The problem presented was to add battery charging. Before you get cutesy and snarky make sure you know what you are talking about, rather than be a Larkin parrot. ...Jim Thompson

I have the full (provocation) thread in a separate directory. If you think I started this, I'll send you a copy.

Larkin is a self-admitted manic-depressive... once he goes off the deep end, he never stops :-( ...Jim Thompson

Either front or rear wheel HUB can be replaced with a hub dynamo. Modern Shimano rear hubs even include a friction brake. ...Jim Thompson

Oh! Finally I see... if _I_ run an architectural behavioral simulation showing that the scheme will work, it's a "cartoon".

On the other hand, if _you_ make a hand sketch, by _declaration_, that's the only proper way?

John, You really do need to see a mental health professional. ...Jim Thompson

I used the Magdowski model, link posted by Marcel.

I've noted in several posts that I was suspicious of the accuracy of that model.

I'll check out your links, out of curiosity... I won't be doing anymore posts on this subject... there's no point :-(

Yep, Ian is certainly an antique :-)

I did point this out also, just change to LED, and you've "loosened up" enough juice to charge an added battery.

Remember my post upon return from lunch at Ra, where I looked over a modern bicycle parked there?

You didn't read my text? Diode D7 was just for illustration purposes... I suggested it be replaced by an active switch. I also suggested regulation via burst mode control via the RESETbar of the

I guess I seriously wasted my time finding out if the scheme had potential?

I'll leave all the "designing" to Larkin... you all deserve it. ...Jim Thompson

If led's are so efficient that a couple of watts is enough, there's no need to multiply the alternator current. No switcher, no transformer. A rechargable battery is a nice idea, to have lighting when you're going slow or stopped. Simple linear electronics is probably all you need.

A uP would be good for sophisticated algorithms, like minimizing the subjective effects of alternator drag.

John

I had found all those. The Magdowski model is best we have. Maybe I'll buy a hub and measure it myself. ...Jim Thompson

So NOW it has drag? ...Jim Thompson

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Go ahead. I didn't read all of it.

It didn't even function like the thing you finally posted. It was just a generic set of buck switcher waveforms.

You never addressesed basic stuff like turning things on and off without blowing up the semiconductors.

I never said that my sketch was the only proper way. I presented an architecture for discussion. The question being, is that the functionality that would work?

In fact, with good LEDs, there may be no need for current multiplication at all.

Another unsupported claim.

Hey, why not arrange as many led's in series as you want, to get the lighting you like? After all, we do have a current source.

John

That *was* the intent.

John

Looks like modern bicycle lights run on 2 AA or 2 AAA, for _100_hours_!

So. If you have a hub (or otherwise) dynamo, you'd need to regulate down to 3V, which, if the Magdowski model is remotely correct, improves the available current and makes the regulation (and charging control) easy... actually overkill.

Perhaps Larkin will grace us with an actual working solution? Why don't you lurkers DEMAND he put up or shut up? But you won't. Sad. ...Jim Thompson

Nope. By your personal illustration :-)

But we don't... the current tails off significantly as you raise the output voltage. If you'd bother to run the Magdowski model into real loads you'd know that... but I don't think you know how to even run LTspice. ...Jim Thompson

The history is simple. I said something disrespectful about a silly MIT press release (really, they do that a lot) and he responded by saying vile and obscene things about my wife.

John

I use LT Spice, probably not as often as you do, bacause I don't design by fiddling. You always have component values available because you do "design" by Spice fiddling.

The corner frequency, the speed where the constant-current-versus-speed region starts, will obviously move up as the load impedance increases. But it's certainly not a constant-power device in general. At any given speed, it's an AC voltage source behind an impedance, and all the normal circuit theory applies.

If, at some speed, you plop the load impedance at the peak of the power transfer curve, sure you'll be on the flat spot. Nothing unusual about that, but that's not the general case. The point is that, at reasonable bike speeds, there's more power available than the lamps normally consume, and you can extract it if you match better. If that's not true, your buck switcher makes no sense.

If you disagree, say something substantive.

John

Conservation of Energy. Since a leisurely pedal down to the pub might take, say, 20 watts of leg power, a few watts of charger kicking on and off might be noticable and annoying. People already complain about hub generator vibration. A commercial product would get bad reviews if it annoyed the rider with erratic loading, so a $1 ARM with ADCs and PWMs and algorithms would be appropriate to control it smoothly. But you don't do that sort of thing.

John

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

I've lost count how many times I've corrected the f****it JT that I *AM* using LEDs - but he's just too thick for it to sink in!

He really is totally clueless and rambling on incoherently aboult what he believes is his own agenda.

Its really sad!

AFAICT - JT's intention is to screw everyone up with deliberate misinformation.

The tail light of my 15 year old bicycle uses a supercap to store energy. It has enough storage to keep the led on for about a minute after stopping. Ofcourse the tail light doesn't need to be very bright.

I'd like to replace the front lamp with a led lamp though.