Bicycle dynamo LED - adding a "super cap" to keep it lighted ( after stopping )

[Speakerguy]

Even if he only bicycles 1% of the time at night, it is still worth it to have lights.

And aren't most of our projects, to one extent or another, impractical vs just buying something?

 

[arhi]

xenagor, not to step on your toes but I removed the dinamo powered system from the bike to add a batt powered system as dynamo just used toooooooo much of the power ...

now, that aside, if you really want to leg power the light ... when you are standing still the back one is "important", the front one isn't that important, right? From the 1-5F 5V5 cap (that you can easily find) you should get ~20-60sec of blinking .. (assume front light is off)... if you want front one to light too, then you have to go much larger cap's and IMHO that's stopps being feasible.

One note, do not use 7805 and similar voltage regulators... pay 1 or 2$ more but get a LDO regulator .. 7805 have 2V voltage drop (1.7 in the best case scenario) and that is just tooooooo much power wasted ... power that you use to go forward .. so get better regulator .. for e.g. BA05T has 0.3V voltage drop or even put extra $$ for some DC/DC switched regulator that are close to "no power loss at all" ... not to mention, BA05 is ~same price as 7805

 

[Boncuk]

Mouser sells the WIMA SuperCap type C (600F, 2.5V, cylindrical shape) for US$37.91. Connect two in series to a 5V regulator and connect front and rear light to the circuit, or use one SuperCap and an LM317 adjustable voltage regulator and set it to 2.5V.

Boncuk

 

[Boncuk]

xenagor, not to step on your toes but I removed the dinamo powered system from the bike to add a batt powered system as dynamo just used toooooooo much of the power ...

I suggest to use an electric motor on your bicyle. That way you won't have to use any body power.

 

[audioguru]

And power the electric propulsion motor from a little capacitor? It might last one second.

 

[Xenagor]

Mmmmm interesting !

I think I got something for ya, it is said to not use ANY body power !

**broken link removed**

Calculate the time knowing that the capacitance of 1F means current flow of 1A for 1 second.

Ahh thanks ! I was looking for an easy formula to get a good idea of the time of discharge for the power taken !

That would mean a 600F would last around 900ish second if I got this right ... pretty damn good. ( 600F / 0.650A = 920sec )

600-650mA which seems like to be the most current my dynamo can output - according something I read. I got no confirmation of this however.

From the 1-5F 5V5 cap (that you can easily find) you should get ~20-60sec of blinking .. (assume front light is off)... if you want front one to light too, then you have to go much larger cap's and IMHO that's stopps being feasible.

Mmmm ... well in theory it seems feasible, even though it might be bit more expensive then I originally thought. I'll have to check this out - maybe I can build the circuit with a cheaper smaller cap and see if it works before investing.


The thing is if I need to buy 2 X 40$US cap, I DID finally found some powered by dynamo LED + standlight ( with a capacitor ).

They are starting at around 100$bucks however, the good ones. The cheap ones only have a very cheap LED while standing ( powered by the cap ), making it enough to be seen - but not close to be enough to light the road.


So I'm gonna stick with the idea of building a cheap one I think, I just ordered a 10$bucks PowerBeam flashlight, very cheap light that I'll feel free to test my things and figure the circuit. ( Even though I know it's quiet simple, just of matter of doing it safely ).


You tell me that I could put 2 of those 2.5V cap and basically make a 5V cap with them ? I wasn't sure if that was possible, since I know that capacitors in series is the same a resistor in parallel for the formula.

I attach an image for my question this time...

Basically, would that mean that those 2 circuits are the exact same, and so will behave the same way ?


Don't bother about the circuit, but only the caps... I just picked the first circuit I fell on.



If yes, it would probably be the easiest solution, however 40$US bucks for each cap is bit more I expected, so I'll have to check, because I don't want to sacrifice brightness for the cost either, but it's almost the cost of a good Dynamo lamp at that point :

Busch & Mller Lumotec IQ Cyo R senso plus with near field illumination (175QRSNDi)

I finally found that model, much more reasonable price than the Supernova E3.. Still over 100bucks though - but my "mini project" cost is getting closer also.


I assume this LED light has a smaller cap however, since I have a hard time beleiving there is a 500Farad in there, and they only mention it takes 3 min of riding to fully charge it - but can't find anywhere how long it will last powering the light.


I also found this website :

**broken link removed**

Which seems probably the best website to compare the different Battery/Hub and Bottle dynamo Headlight. ( If anyone is interested )



Whatever I do I'll have to wait for my cheap LED Headlight I ordered and try my stuff from there, hoping I'll figure something not too expensive


So what about those circuit .. ? Circuit A = Circuit B .. ?


Thanks a lot for the pricing Boncuk ! I think I'm gonna check if a 100Farad 5.0V would be cheaper, I think I saw 1 on the WIMA website !

 

[Xenagor]

Meh I attach the wrong image. Here is the right one.

 

[tcmtech]

Gosh your determined! I am almost starting to respect you despite your being a bike rider!
Also your right about the capacity change due to stacking. If you put two 2.5 volt 600F in series you will have the equivalent of a 5 volt 300F.

I am wondering about the super caps being used in series though. Being voltage sensitive if the capacitances are not exactly matched one will get over charged and burn out.

When decide to put an electric motor on that monkey mobile then I will respect you!

 

[Boncuk]

I am wondering about the super caps being used in series though. Being voltage sensitive if the capacitances are not exactly matched one will get over charged and burn out.

Those SuperCaps are not manufactured in China, but in Germany! Never heard about German precision work?

 

[Boncuk]

Meh I attach the wrong image. Here is the right one.

No matter how often you post that circuit it won't change to be utmost dangerous. There is no charge voltage limiting circuit for the caps

(If you're are planning on SuperCaps you have to take care not to exceed the maximum allowed charging voltage, otherwise SuperCaps can be considered bombs)

Boncuk

 

[Sceadwian]

Super caps are expensive as well. 5V 1 Farrad caps will set you back 9 bucks. Damn nice though, I modified a cheap hand crank LED flash light to use a Powerstor one instead of a battery, charges in only a few seconds of some stiff cranking, ESR is pretty high on the one's I got (1.5 ohms at DC) but they make much better ones. I should have bought a lower ESR one myself but they were an impulse purchase, still have a couple kicking around.

 

[Dotnet]

I suggest to use an electric motor on your bicyle. That way you won't have to use any body power.

Don't say that - he'll stick a dynamo on his bike (via a supercap) to feed the motor.!!!!!

(I've discovered perpetual motion - cough cough)

There will be so much metal on his bike he won't need lights because when a Hummer hits him at a traffic light - the Hummer will come of worse he! he!

Serously - listen to people here (well the ones not PLEADING for help with their homework) there's ways of doing things..
At the end of the day you want light - LOTS OF LIGHT you need to feed your LED, Lamps, Bulbs, Hallides, Plasma injectors whatever by batteries. I would strongly suggest you use the dynamo to 'top up',(ish) batteries - Lithium Ion. Work on a battery boost when you brake - but use batteries, worst case scenariou you take of at home and charge them.

Matt

 

[Boncuk]

Don't say that - he'll stick a dynamo on his bike (via a supercap) to feed the motor.!!!!!

(I've discovered perpetual motion - cough cough)

There will be so much metal on his bike he won't need lights because when a Hummer hits him at a traffic light - the Hummer will come of worse he! he!

Serously - listen to people here (well the ones not PLEADING for help with their homework) there's ways of doing things..
At the end of the day you want light - LOTS OF LIGHT you need to feed your LED, Lamps, Bulbs, Hallides, Plasma injectors whatever by batteries. I would strongly suggest you use the dynamo to 'top up',(ish) batteries - Lithium Ion. Work on a battery boost when you brake - but use batteries, worst case scenariou you take of at home and charge them.

Matt

Hi Matt,

I've absolutely no problems generating electric power pedal driven. Grandma sits on a byce (without wheels to save weight) 12 hours per day and generates the necessary electric power the kids require to watch their fancy TV-shows.

As soon as Grandma falls off the byce unconscious there is no electric power for the TV and the kids go to sleep.

Don't be worried about Granny. The entire area around the byce is well wadded so she won't get hurt.

Granny might be considered a "perpetuum mobile" since she generates 1.2KW daily with little food.

Boncuk

 

[tcmtech]

Those SuperCaps are not manufactured in China, but in Germany! Never heard about German precision work?

Yea I've heard of precision German work. That Hindenburg worked real well!

So did the WWII tanks that got their butts handed to them by the crappy American tanks we admit that we half assed built!


I am also starting to see that the few hundered dollar build price I mentioned is not looking to be that far off now!

Amost makes a guy wonder if I didnt do some practicality research relating to ultra caps as power sources at some time.

Granny power huh? Why not make the kids do the work for their shows!
Then they will go to bed sooner!

 

[audioguru]

Yea I've heard of precision German work. That Hindenburg worked real well!

Didn't you see the very fast British destroyer ships in the South American Falklands war? They were made of lightweight magnesium and caught on fire like a match. Maybe they were hydrogen powered too.

 

[Sceadwian]

I didn't think solid magnesium would burn very well?

 

[tcmtech]

Believe me when you get it hot enough in one spot thick magnesium will burn very well! And then it will just keep going!

I have had a few locals bring me "aluminum" parts for vehicles and farm equipment over the years in order to get them welded.

About ten seconds into the weld is when it becomes clear that its magnesium and not aluminum!

I just keep the welding helmet on and watch it burn!

 

[audioguru]

When the Argentine missles hit the British magnesium destroyer ships then the ships burned with a very hot white flame.

 

[Sceadwian]

That's about all you can do with magnesium, it doesn't like to be put out.

 

[tcmtech]

I occasionally do some magnesium welding but when I do it I absolutely go nuts with the shielding gas flow! And after I stop welding I keep the shielding gas flow on it until it cools down.
Its when I dont know its magnesium and just assume its an aluminum alloy of some type that I jet the uncontrolled burn going! By then its usually to late to run over and turn the shielding gas flow up.