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What we have here is another entry into the "self
powered", or more accurately called "human
powered", led flashlight arena. This is a close-to-final
prototype for a hand-press LED flashlight being designed
by Unigrip Custom Products Group, a small business in
Florida. They set out to make an inexpensive but good
functioning hand recharged LED flashlight in the $5
- $7 retail price range. Considering their goals, I'd
say they did a pretty good job.
Now I have seen a similar light, and in fact it's mentioned
on my "Fakes, Frauds,
and Fallacies" page since it actually had two
non-rechargeable coin cells inside that ran the LEDs.
When the cells died, there was no recharging them. Squeezing
the handle only lit the LEDs as long as you kept squeezing.
What utter junk! This new light uses tiny NiMH cells
to hold the power and not only does it actually recharge
the cells, it recharges them quite rapidly. Much better!
I wonder why the folks who made the fake light didn't
think of that...
Body: Now you have to keep in mind that one
of the design goals was to keep the price in the "very
affordable" range. It is robust enough to be used
as intended, but abuse will likely cause it to fail.
The body is polymer with a squeeze handle which spins
a gear, which spins a generator, which sends electricity
through a little circuit to the 40mAh NiMH button cell
pack. This charges up the batteries very quickly (we're
only talking about 40mAh here) and is able to produce
light with just a few squeezes.
Three metal screws hold the body together, but don't
take them out unless you want to sit there cussing at
the spring that works the handle as you try to put it
back together. Also, the wires from the generator to
the circuit are VERY thin and could be damaged rather
easily if the unit is disassembled.
I've been cranking at this thing for quite some time
and it shows no sign of failing yet. No stress fractures,
no breakage, nothing.
Bezel/Head: At the front of the unit are 3 white
5mm LEDs in a silvered plastic reflector behind a plastic
lens for protection.
Output: The white light produced by the LED
is has a slight bluish hint but still produces good
color rendition. The hue is detectable when compared
against a near sunlight-white source, but is not really
noticeable during normal use.
Beam at one meter at target center
Runtime Plot: Here is the first run, without
any significant discharge from when it was received,
but with about 1-2 minutes additional charging. I ran
it right down, just like a kid camping in a tent might
do...
Runtime
completed with internal batteries. More information
on runtime plots is available HERE.
Not bad, but I've seen similar performance
from those inexpensive wind-up lights. Having learned
about how these human powered charging lights work,
I know that the real tell-all is in the second full
discharge. I charged it up for about 3-5 minutes worth
of squeezes and then let it rip...
Runtime
completed with internal batteries. More information
on runtime plots is available HERE.
Uh-oh. This doesn't look good. In about 5 minutes it's
down to 25%. No where near the performance of the first
run. Shall we try for three? I'll give it at least 1000
squeezes for this next run...
Runtime
completed with internal batteries. More information
on runtime plots is available HERE.
And there it is. 1000 squeezes at 2/sec, so that's
8+ minutes of continuous charging on top of a bunch
of squeezes I gave it after the second discharge just
to get the voltage back up in the cells.
As an experiment, I next took 4AA cells (6V) and held
the connection wires to the pads on the internal circuit
board to charge the little 40mAh cells with the AA cells.
I know this works because I have a little tiny remote
control car with 3.6V button cell rechargeables and
it charges with 4AA cells. After about 2 minutes of
touching the pads the brightness of the light jumped
right up, and voltage was now up to 4.0V. Nice! I ran
the runtime test again and once again there was less
than 2 minutes to 50% output.
I'm beginning to suspect that either 1) these cells
need a lot of energy to charge up, possibly more than
the rotor can provide in a reasonable amount of time;
or 2) the cells were damaged when I ran them down for
1 full hour.
I am expecting a production unit when they are ready
(this is still a prototype) and I'm planning on running
that one down 20 minutes and charging it back up as
recommended by the maker, and then doing another runtime.
This should eliminate the chances of damaging the cells
due to excessive rundown.
Switch: At the front of the unit (left in picture
below) is the simple slider switch. Forward is on, back
is off and recharge. You can pump the handle while it
is on, but it just makes the LEDs light up a little
brighter. The switch on the back (right in the picture
below) has three dots on it for identification in the
dark. This releases the squeeze handle when moved rearward,
and retains the handle in the up position when pressed
forward.
Seals / Water Resistance:
Keep it dry if at all possible. No seals of any sort.
Ergonomics: This little light fits the hand
well and is very easy to operate. In fact, it's the
easiest hand-recharged light to use that I've experienced.
I remember having one of those old incandescent hand
squeeze lights and after using it for a few days your
arms would start to look like you've been bodybuilding.
This one just glides easily. Sure you have to apply
a little pressure, but nothing uncomfortable to work
with. Helpful Hint: squeeze the handle as far back as
you can (away from the hinge) to get the most leverage
and ease of use. When you squeeze it, the gears and
rotor will give a winding sound, which is normal.
Size compared to a common 2AA aluminum light
Batteries: The internal 40mAh 3.6V NiMH battery
pack (3 button cells @ 1.2V each) store the charge from
your efforts for future use. They are not user serviceable,
but considering the expected price, when they finally
refuse to keep a charge just get a whole new light.
Squeeze to charge em' up!
Close-up of the little batteries that hold the charge
(green, at top).
Accessories: A very short lanyard is attached.
I'd call it a "finger" lanyard - enough to
get about 3 fingers into to keep from dropping the light.
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