400 Farad Super Capacitor Flashlight. Build This One. It's Easy.

Picture of 400 Farad Super Capacitor Flashlight.  Build This One. It's Easy.

Wouldn’t you like to have a flashlight that does not need batteries that will last a lifetime? Wouldn’t it be great if you didn’t have to shake it every few minutes to keep it lit up? Then what you need is a super capacitor flashlight.

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Step 2:

Picture of

The pen light is easy to take apart. The gray plastic part with the lens unscrews. Pull off the black ring. Pull the board out of the white plastic tube. The black wire on the board will be connected to a metal contact on the side of the white tube. Cut the wire at that contact.

luxstar (author) 2 years ago


I have been running tests with different motors of various sizes.  I have a test set up with a large wheel with a crank/handle on it to step up the rpms on the motors I have tested.  It is easy to light up leds with motors but charging a large super-capacitor is a lot harder.  My goal is to get 1 hour of light for 2 minutes of cranking.  I have only one motor (out of the 20 or so I have collected over the years) that is big enough to meet the goal but it is too big to be portable.  I have given the half-hearted effort to making a generator but that has not met my goal.  For now I am not pursuing it since the overall goal was to have a way to have lighting off the grid and without batteries for an extended period of time if necessary.  That goal can easily be met by having:

 A solar panel as small as 5 watts

A junky old car battery (does not have to be good enough to start a car).

A 12 or 14 volt linear regulator (LM7812, LM7814)

A charging circuit for this flashlight.

And a couple of super capacitor flashlights.


So since I have the great big motor in case there is a problem with the solar panel / car battery set up, I’m still prepared.  If I do pursue the generator thing in the future I have my eye on this one to connect to a bycicle:

$49.00 here:

I Think I will only be needing 2- 3 amps at under 6 volts.  After 2-3 minutes on the bike I get on with my life.  Thanks for the comment Drakekay.

luxstar (author)  luxstar2 years ago

The Solar set up mentioned in the Sep 10, 2012. 7:03 PM comment is here:\


luxstar (author) 2 years ago

By the way if you don’t want to build a supercapaitor flashlight but you would like to own one, here is a review of the Lightstorm CL1 flashlight with a crank:

It looks like a good option if you don’t mind winding every 20 minutes. The high beam appears to be very bright. It is a mechanical device with gears so it will wear out over time if used often. Perhaps owning both is the best of both worlds.

Drakekay2 years ago
Hey Luxstar, Greet concept. :D Why not add a hand turned rotor with magnets attached to it, encased in a coiled stator to charge that cap?
luxstar (author) 2 years ago

Note: When I ordered my capacitors I accidentally clicked on the 2.5 volt capacitor instead of the 2.7 volt. They make both. So I am stuck charging at 2.5 volts. Don’t make the same mistake I did.