Hand Cranked Flashlight Mod plus Joule Thief

Hand Cranked Flashlight Mod plus Joule Thief
I have a couple of hand cranked flashlights laying around and I was never satisfied with their performance.

When I got them fresh out the box they worked great. But when their batteries ran out it was too exhausting to recharge the batteries manually. And after a couple of years, it was almost impossible recharge the batteries because they were too old. Now, a hefty 5 minutes of cranking produces only 20 seconds of light.

I decided to mod one of the flashlights by switching the lithium ion rechargeable battery with a super capacitor.

Surprisingly, the mod was easy and the results were very satisfying. Now, with just a mere 5 seconds of cranking I get 5 minutes of light. A major improvement.

In a further mod I added a joule thief which increased brightness (see step 5)
 
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Step 1The Back Up Super Capacitor

The Back Up Super Capacitor
A super capacitor acts like a battery in computers and electronic devices, and therefore it can serve as a back up power supply.

The neat thing about super capacitors is that they last much longer than rechargeable batteries. They are easier to recharge because they have almost 100% efficient while the batteries lose between 50% to 30% of the energy when recharging.

I am using a 1 Farad super capacitor. But you can use bigger values. The bigger the super capacitor the longer the flashlight works.
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21 comments
Oct 21, 2011. 2:22 AMcurious youth says:
how would i go about doing that for one of these ?
http://media.uxcell.com/uxcell/images/item/catalog/ux_a06070700ux0009_ux_c.jpg
aswell as the fact that im modding one to make a hand crank phone charger from this instructable
http://www.instructables.com/id/Hand-crank-LED-flashlight-hacked-now-also-USB-ch/
Jun 5, 2011. 5:51 PM-max- says:
you should consider replacing the leds with brighter ones.
Oct 23, 2010. 10:38 PMdjzadjza says:
sweet
Sep 26, 2009. 10:12 PM808create says:
Also, what kinds of household electronics can capacitors be pulled from?
Nov 5, 2009. 7:04 AMJodex says:
Kinda from anything..=D
Sep 23, 2009. 11:28 PM808create says:
Will a capacitor last forever, theoretically?
Aug 31, 2009. 3:02 PMbahi says:
Very useful, thanks!
Jul 16, 2009. 7:17 AMPasketti says:
Where did you get that capacitor? I have several of those lights. The only supercapicitors I've been able to find won't fit in the space available.
Jul 14, 2009. 8:29 PMmikedoth says:
I'm going to order a bunch of these suckers. I have a couple of these lights and they suck (and luckily I haven't taken them apart yet for other projects). This might make them useful after all!
Jul 15, 2009. 2:48 AMPazzerz says:
If you have a Harbor Freight in your area you can pick them up there. I have one of these and this sounds like a good mod. If a super capacitor can outlast the little lithium ion battery, then its worth it.
Jul 15, 2009. 5:34 AMScott_Tx says:
I'd say so, I think most are rated for at least a million cycles
Jul 15, 2009. 5:10 AMPKM says:
Is that part under "battery charging circuit" a one-way rectifier without the diode voltage drop? That's pretty cunning. Are capacitors 100% efficient? I thought they were only ever 50% efficient, sure I remember deriving that in A level physics. Still, from an engineering point of view they sound much better than the old batteries. If I can find a place to get them around here there might be a bike light 'Ible in it.

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