The latest fad has been these flashlights that you shake to charge.
They contain a coil and magnet which charges a capacitor and lights
the LED. Well, they do work, but to keep the led bright you have to
shake them almost constantly.
I know many of you have played with them in the stores and say they
stay bright forever. WRONG......
These flashlights which are sold as batteryless, actually contain 2
flat disk batteries. Thats why you never have to shake them when new.
I dismantled one, and found the batteries. I removed the batteries
and they work without the batteries as long as they are shook almost
constantly. They stay on for over an hour after being shook, but the
light is so dim it's useless, and a match is brighter.
Once again we as consumers, are being deceived by the advertisers.
A good buddy bought 2 at the rodgers ohio flea market. You did way
better than he did.
His flashlight worked off those 2 batteries but they went dead, and
shaking didnt work:(
It turned out the thing that shakes wasnt magnetic, which is needed for
charging and the little board was bad. My buddy is a retired
electronics engineer and found them interesting....
There have een other reports too, from tampa of the complete junk type.
one could put D cells in that unit and with the LEDs small current draw
have light for days.
so you did good at least it wasnt pure junk...
I have seen two dollar stores in the western suburbs of Philadelphia
selling $2 shake flashlights. The packages were different.
In both cases the magnet was fake, the coil was shorted, and the circuit
board had no energy storage device other than non-rechargeable "coin"
Meanwhile, I have heard of $2 shake flashlights that are not fake,
although I wonder how well they actually work.
Meanwhile, higher price shake flashlights do work, although many to most
are not that bright and don't maintain their brightness for long. Some
have both batteries and the shake-generator stuff.
One that was on display at a local hardware store so that people could
try it out did not work well, needing to be constantly shaken to provide
any decent light that was still less than that of a typical LED "keychain"
It appears to me that the $30-$40 units at Target are pretty decent,
although they still have only one low-power LED and I expect them to
underperform a 2-AA size Mag Light.
Now for some review links in the "LED Museum" / "Punishment Zone"
site, http://ledmuseum.home.att.net :
http://ledmuseum.candlepower.us/second/shake2.htm - a "Diamond" unit
http://insulatorz.home.att.net/night1.htm - a "Nightstar" unit
http://ledmuseum.candlepower.us/fifth/shakefl2.htm - a dollar store fake
http://ledmuseum.candlepower.us/fifth/shakefl1.htm - a dollar store fake
- Don Klipstein ( email@example.com)
taken apart had 2 small batteries in them. The markings on the batteries
were standard battery types. The 'magnets' in them were not even real
magnets. They would not attract any metal.
The lights would burn about a day without shaking and never light again.
I have only seen one and it appeared to be real. The run time varied up
to about 15 minutes after shaking and would come back up when shaken. It
sounds like some of them out there are not the real thing. Frankly I don't
have a lot of interest in the real thing as the battery powered units should
run long enough for any of my uses. I have several battery lights around the
house and they all still work and I don't think I have replaced a battery in
over five years.
I have seen three types of these "genlights".
One is obviously fake as it is powered by two coin cells, has no
magnet and no components on the circuit board. Batteries seem to have
One has 2 rechargeable cells and does in fact charge the cells when
shaken. It has magnetic slide and board is populated.
One has a large capacitor charged by the shaken magnet. The board is
May be other types but these three are in the markets. Both the latter
types work fairly well as an emergency light source.
| I have seen three types of these "genlights".
| One is obviously fake as it is powered by two coin cells, has no
| magnet and no components on the circuit board. Batteries seem to have
| poor capacity.
| One has 2 rechargeable cells and does in fact charge the cells when
| shaken. It has magnetic slide and board is populated.
| One has a large capacitor charged by the shaken magnet. The board is
| May be other types but these three are in the markets. Both the latter
| types work fairly well as an emergency light source.
Walgreens had a $5 "sale" on these a few weeks ago. There was a whole
shelf full of assorted types, many of which were just broken. Of those
that worked, most were the type with two coin cells. Some, however,
had a single HiMH battery (I'm trusting that they didn't fake the label
on the battery) and a correctly wired bridge rectifier actually connected
to the coil... plus a real magnet. I bought one of these. Of course,
the battery is charged so it's hard to say whether it works. If it
doesn't charge once it runs down maybe I'll try replacing the battery
with a super cap, assuming the coil is indeed putting out voltage.
I took one apart, and the flat disks were large hearing aid batteries.
Both wires from the shaker coil were soldered into the same hole of an
unstuffed PC board which might have charged the batteries charged if
it had been correctly assembled.
Did you check to see if the "magnet" attracted steel objects? I
disassembled two different $2 units, and got your findings as well as
finding that the "magnets" were not magnets. In addition, the batteries
that I found were CR2032, which I do not believe are rechargeable.
- Don Klipstein ( firstname.lastname@example.org)
email@example.com (Don Klipstein) wrote in
amazing they can make a flashlight with TWO expensive CR2032 lithium cells
and sell it for TWO bucks and make a profit.
(mine was $3 at a 'doller' store;it appears to have two coin cells,which I
had wondered about,THX.)
Yes, they are batteries, (button type) in fact it says "lithium
battery CR2032 3V" on them.
At least I have a real magnet in mine, and likes to snag all the nails
and screws that end up in my pocket. And, as I said, the shaking does
light the LED to full brightness, but only for 10 or 15 seconds
without the batteries. Then the light remains dimly lit for another
half hour or less. There is a capacitor in there which charges from
I dont think lithium batteries are chargable (but I could be wrong).
Either way, without the batteries, almost constant shaking is needed
to maintain a bright light.
On Fri, 12 May 2006 11:23:32 GMT, "Joseph Meehan"
I've seen 3 shake flashlights, on one the capacitor is 1F (1 Farad),
the second it's hard to tell but looks like .5F, the third (a small
one) has .1F. There are no batteries in any of them.
That small one is essentially useless.
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