Battery-less LED flashlight

[gech375]

I think everyone is missing the point here,
Please don't think I am rude but everybody is talking about charging batteries and the question is how to make a batteryless flashlight using
a capacitor like the shake lights that you see on tv,
if they didn't work they wouldn't sell them on tv,
I too am trying to make one of these flashlights for a fun project not for
practicality but it would be practical if it worked well, I have many capacitors and have searched the internet hard for the answer with not much luck so the question is again does anybody have one of these flashlights that they have taken apart to see what components are inside
and list them on here so the rest of us can build from that diagram?
Thanks,

 

[Nigel Goodwin]

I think everyone is missing the point here,
Please don't think I am rude but everybody is talking about charging batteries and the question is how to make a batteryless flashlight using
a capacitor like the shake lights that you see on tv,

It's still to the point, charging a battery isn't really any different to charging a capacitor.

if they didn't work they wouldn't sell them on tv,

As you didn't insert a smilie there, I can only presume it was a serious comment? - in which case it was unbelievably naive!.

I too am trying to make one of these flashlights for a fun project not for
practicality but it would be practical if it worked well, I have many capacitors and have searched the internet hard for the answer with not much luck so the question is again does anybody have one of these flashlights that they have taken apart to see what components are inside
and list them on here so the rest of us can build from that diagram?
Thanks,

As already suggested in this thread, you need a 'super cap', something in the farads range. The electronics involved is simple (actually crude!), the clever part is the mechanics of the charging mechanism.

Check this old thread which has pictures of a dismantled torch, plus links to a manufacturers datasheet .

 

[Oznog]

You gotta find out about the "supercaps" you're looking to get. A lot of those have incredibly high output resistance, like 10's of ohms. This significantly limits how much current it can put out and also limits how fast it can charge.

There are current mode buck converters which do a great job of changing high voltage to regulated LED current very efficiently. HV9910 is a good one. But it's still HV here. It's dangerous to touch and requires HV to charge. Like all caps there are various degrees of self-discharge here and the power storage per unit of mass or volume is pretty poor compared to batteries.

 

[alimokoi]

hope this could help

https://www.electro-tech-online.com/custompdfs/2006/08/Induction.pdf
just check it out, and tell me if it works coz i want to built also wid my own.

 

[audioguru]

After shaking it vigorously, they showed a graph of its stored voltage dropping but I couldn't see how many seconds the LED was lit as its brightness faded away. I tried one in a store and the LED was dim then dimmed to nothing in about 10 seconds.

 

[Nigel Goodwin]

If it's of any interest?, this months EPE has a project for human powered LED torches, using stepper motors as generators.

 

[HiTech]

LMAO... leave it to China to name one of their flashlights "Old, Long, Cheap"! Next they'll offer a disposable model called "Who Flung Poo". While some of those "tacticle" lights look the part, they are far from what manufacturers like Streamlight, SureFire, Maglite, etc. produce.
I own more flashlights in various sizes, lamp types, etc. than some members here stockpile electronic components. There are varying qualities of xenon, halogen, and krypton bulbs with some of them producing not much more output than a standard lamp. The same goes for "ultra-bright" leds. Reflector and lense design and quality is also a very important factor. I have a "shake light" that is pretty decent IMHO. I also have a dynamo powered incandescent flashlight that also works rather well. But there is no other favorite of mine other than my Luxeon and Nichia LED flashlights. I always take extra effort to know where those are lying about and always reach for them as first choice. The Streamlight is a quality product that could withstand any environment on this planet short of being tossed into an active volcano.