) writes:
ve3... wrote:
Several months ago I reviewed a LED flashlight that used a magnet
sliding through a coil to generat electricity. There were posts that
stated that some Chinese LED flashlights on the market were fakes using
button cells that could not be recharged. The moving slug was just put
in to look good. The one I bought from PRO Hardware was legitimate and
has worked perfectly for three months with very little charging
required. One way to identify a good moving-magnet flashlight is to
put it near some paper clips or such. The magnet is so powerful that
the clips will jump at the flashlight and stick to the side. The
flashlight in question is 7 inches long is made of clear plastic and
has a black ring at the front. It is PRO Hardware number 736N5950. I
imagine that there are lots of them around and they would make good
stocking-stuffers for those of the Kris Kringle persuasion (not that
there's anything wrong with that).

The two that I tried provided a weak light with limited electrical
storage given the size of the flashlight. In an emergancy you want
light shining on the object an hand without having to periodically
shake the light. It's really little more than a gadget for xmas.

Well it depends. An ongoing emergency, obviously you want a constant
light since there'll be no other.

But "emergency" can mean a blown fuse, and a need for a light to check
which one. Or checking something in a dark corner merely because the light
isn't good there. The advantage of having a flashlight that doesn't use
batteries is that one can just crank it up when needed to get that bit
of light. Time will tell whether the current crank or shake lights serve
that purpose in the long run.

I can remember with incandescent flashlights, how often when I actually
needed the light the batteries were dead. Maybe bad shelf life, but
I'm beginning to think the switches had too little resistance in the
off position, allowing for a constant current drain without enough for
the bulb to light. So you'd not notice that the batteries were draining,
but the batteries were gone when you needed them.

This is amplified by the bulbs themselves not putting out much light
with the lower battery voltages. When I got an LED adaptor for my
Maglite last year (it just fits in where the bulb used to go), I started
off with batteries that had seen use with the incandescent bulb, so they
were worn out at least partially. The light kept going, until I realized
that "oh, the light has become weak, time to change the batteries". The
incandescent bulb would have changed color and put out less light long
before that.

And of course, the bulbs would break or burn out, and then you'd be
stuck with no light. At least LED flashlights aren't going to have the
breaking problem, and it will be some time before they burn out.

So on some level, the cranks and the shakers may be less necessary with
LED flashlights, since they work better with lower voltage. But then,
that's why the cranks and the shakers have come along at this time, because
the LEDs work better than the incandescent with lower voltage and current.

Michael