I have a great "shake" flashlight. It has two large copper coils, I believe a big capacitor and some electronics and it holds a charge for months. When shaken for two minutes you have power for quite awhile, I've never tested it for maximum time. It's called "New Deluxe Forever Flashlight." I believe the company was "itouchless.com" It cost me about $20.00. I've had it since April and have used it quite a bit. Of course, it's not equivalent to the power of a battery operated light, but it's fine for in the house or yard. Just think what one of these would be worth if no batteries could be obtained!

I have 3 shake lights in various sizes. I have one that will hold a charge for days. I don't know the brand. I have a small one that I keep in my EDC that I have to charge everytime I need it but I think that it gets rolled around in my bookbag and the light gets turned on. I have a larger light that I carry in my truck and I am not as pleased with it. It will hold a charge but the light is not so bright. Maybe I just need to charge it longer. If one of these does discharge completely it has to be shaken for about 3 minutes. Not so good if you need light ASAP. Except for this little problem I think they are great to have around for emergencies.

Decided to pick up one of the cheap shake lights. Looked over good to see if it was broken etc. worked good. Son dropped it on concrete and broke it. On other hand, my son got me a brinkman led flashlight. Little large but it is the first LED Spotlight I have seen.

I have bought several types of shake lights for my kids and found them to be pretty darn good. Bright enough to get around in the dark and rumage through your pack. Mine have all held charges for months. In fact, I haven't had one go out on me or my kids yet.

The kids have their play ones, which they use periodically, and shake all the time. I got tired of constantly replacing batteries in flashlights that they left on.

Also, I order a bunch of these for our 4H group as I built their little back packs up:



They are cheap (under $3 per) and seem to last pretty long. They are bright and hold a charge. I wanted shake lights, in addition to the fauxtons attached to their packs, to give the kids something to do if they get lost in addition to signalling.

I wish I had seen those $3 ones before I spent $20 for a set of two of the "as seen on TV" lights.

The large one is supposed to be waterproof and can't be taken apart, but the small one's bezel can be unscrewed and the guts come out. My toddler son did this three times and I was miraculously able to find all the parts each time before I finally glued the whole thing together permanently.

Before I did that, I took a look at what makes it tick. The two wires from the coil connect to a bridge rectifier, which charges a .1 Farad 5.5v supercapacitor. The LED connects to the cap through a mechanical switch. There is no current-limiting resistor but the cap has significant internal resistance that takes care of that. Very stingy minimalist design. Enough to work, but not very well.

While the electronics could be made better, the real limitation of this device is the magnet & coil generator. It is just very poorly matched to the load and source of power (shaking). The magnet is not perceptibly slowed as it passes through the coil, which means very little power is being generated during each shake. A 50-cent motor from a toy car, coupled to a crank or lever through a gear train makes a far superior generator.

It serves its purpose for keeping a toddler busy until he falls asleep, but it would be very frustrating to use for some critical task in an emergency. It is actually worse than nothing, as someone might depend on one of these instead of buying something much better such as a $1 keychain led light.

I'm solely a consumer of bass pro, not an employee or affiliate in any way.

I have used:
$9.99 38-612-962-11 NO-BATTERY SHAKE FLASHLIGHT 7-1/2''
From www.basspro.com for several years. It has a capacitor and a single LED with reflective mirror. It's made out of ABS plastic.

About 2 minutes of shaking is good for 30 minutes of use. Durable, sufficient light for emergencies. I like it though I keep a real d cell batt flashlight too. It's definitely nice for redundancy though. I was surprised most by how long the light lasts on a minor amount of shaking.