Those new "wind-up" led flashlights and lamps

I just bought a cheapie squeezum lcd flashlight.  Just as a test, we squeezed the dynamo handle a few times and turned on the light ............. last Saturday!  With no additional squeezing, it's still shining today (Thusday).  Amazing.
 
I can't help but wonder what the power storage medium is in these devices.  Is it a rechargable battery, or is it some kind of long-lived capacitor? 
 
Has anybody had one of these devices for a long time?  Is it still working? Any difference between units of equal size that cost $3, versus one that costs $20? 

Dang!!!  My rip cord one doesn't last more than a half hour, but it is very bright and is easy and quick to charge.  In addition, it can have a DC converter plug into it so I guess it's a hybrid!

Jerk-off lights FTL.

So falk, you're saying that squeezing works better than pulling???
 

Nah ..... I'm saying that squeezing or pulling works better than jerking!!!   Of course I'm refering to the lights that feel like they have 1 battery in a 2 battery chamber.  What were you referring to???

I have a cheapy wind up one thats in the trunk of my Accord for emergincies.  Havent really used it much but the winding to light ration seems reasonable.
 
Yeah, the jerking ones suck.

Dang, now I have to figure out if I want to get a squeezzy, pully or a jerky ..I guess I can try all three of them out
 
                           WheelBrokerAng

The experiment continues.
 
The light was still on today - exactly one week after turning it on, with no additional squeezing - so we decided to end the expriment.............. we thought.
 
We turned the switch off.  The light went out.  And then we started squeezing. 
 
The problem is that after probably two or three hundred squeezes, the light is only a bit brighter.  It is going to take a great number of squeezes to get the light back up to its original brightness.  The thing was only $1, so maybe we'll just toss this one and buy another.  After all, time and effort are worth something.
 
Therefore, I believe that the storage device in our particular light is indeed a small rechargeable battery.  The battery is fully charged when you buy it and it acts like a reservoir of power. If it is not recharged, the intensity of the light diminishes very slowly over time, but it's better to spin the dynamo a few times before or during each use so that the battery remains charged.
 
From reports I've read about other styles of lights, their storage device must be a capacitor.  They provide light for only a short period of time after the dynamo stops, but the light come back up to full intensity after just a few cranks, squeezes, pulls, jerks, or whatever.
 
I think the capacitor type is a better design because one HAS to run the dynamo frequently.  That way, one doesn't get away with getting too deeply in debt to the "power bank". 
 
Of course if one is in trouble and for some reason cannot run the dynamo, then the battery-type would give light for much longer.

why not take it apart and check?

I have one of those $40 Grundig am/fm/shortwave/flashlight radios with the dynamo crank,
it has one of those cordless phone types of batteries in it, problem is, after one year of
use (or non-use) the battery won't hold a charge anymore.   And I DO crank it once a
month.

I also have one of those 'shaker' flashlights (the 'official' name escapes me at the moment..)
I shake it for 60 seconds, it gives off usable light for 2-3 hours. 

FWIW

I know there is a Hummer brand of those shaker lights sold at The Sharper Image.  Not worth all the extra cash though.

quote:

ORIGINAL: Fredman

I have one of those $40 Grundig am/fm/shortwave/flashlight radios with the dynamo crank,
it has one of those cordless phone types of batteries in it, problem is, after one year of
use (or non-use) the battery won't hold a charge anymore.   And I DO crank it once a
month.

I also have one of those 'shaker' flashlights (the 'official' name escapes me at the moment..)
I shake it for 60 seconds, it gives off usable light for 2-3 hours. 

FWIW

I've done some more research on these things.

The vast majority have rechargeable batteries, including our $1 jobbie.  The problem is that, exactly as you say, the rechargeable batteries have only a limited lifetime of recharges and the shelf lives of these batteries ain't that good, either.  A quality capacitor can be recharged several hundred thousand times.

Here is one that apparently has only a capacitor, but I'm not sure I believe it.
http://www.associatedcontent.com/article/44056/product_review_durapro_megabrite_997516.html?cat=15

And here's a site that has a buyer's guide for these devices, including information about how power is stored:
http://www.modernoutpost.com/gear/buying_power_flashlights.html

After having learned what I've learned, I would not buy a "wind-up" light that has a rechargeable battery for power storage.  The thing is likely only going to last a couple of years, at best.  Better to get a small led light and put these in it:
http://www.energizer.com/products/hightech-batteries/lithium/Pages/lithium-batteries.aspx
Notice the shelf life.  We use these batteries in an outdoor, wireless temperature-sending unit for the "weather station" sitting on our kitchen table.  The batteries have lasted over 1.5 years in all kinds of weather, including -30 C.  Energizer claims that these last 7 times longer than alkaline and I believe it.  In a small led flashlight that is used only infrequently, they and the led "bulb" should last virtually forever.

If I were going to buy a real emergency "self powered" light, here's the one I'd get:
http://www.modernoutpost.com/gear/details/gg_shakelight60.php
It has no batteries whatsoever and is also supposedly waterproof.  One minute of shaking supposedly gives 60 minutes of light. (100,000 60-sec recharges will therefore give 100,000 hours of light.  100,000 hours equals 4,166 days, or 11.4 years, and, remember, these things can be recharged "several" hundred thousand times.)

i have the one that has a handle and u turn it... it doesn't hold much, prob a few hours if you turn it like a zillion times!