This improved version of battery was the self contained dry cells.
These self contained
dry cells were more beneficial than the led acid batteries, because
they were smaller and were
much more reliable. During the same period, a new kind of led
flashlights was developed. These
led flashlights were named as the dynamos. Dynamos are the led
flashlights that make use of
the energy, which is created by the movement of the led flashlights.
Dynamos became popular
and much more practical at that period of time, because the storage
density of batteries was not
too much. Dynamos proved to be much more practicable during that
period of time. Not every
part of the world had laws regarding the compulsion of having led
flashlights. In UK the led
flashlights group actually went against the law of led flashlights
having the rear lights. This was
because; they thought that this law will reduce the significance of
the motorists obligation to
stop when they would see a bicycle within a clear distance.
What the f*ck are you rambling on about?
You do know that many of those "dynamo" flash lights that were
supposedly powered by movement, actually had tiny batteries in them to
run the lights... Because the LED was so efficient a little button
cell could be hidden in the head of the flashlight and would run it
for many hours.
The "shaker" and tube of copper wire was all for show.
email@example.com wrote the following:
I think samaden was PUI. Posting Under the Influence.
He asserts that flashlights had lead acid batteries.
Lead acid batteries are used in automobiles.
(did you have to check the water level occasionally?)
Coolest flashlight I ever had was a "moon" or "space" flashlight,
which I bought new in the early 70s. It was supposed to be a spinoff
from space technology. It was about the size of a 4oz can of
mushrooms, maybe an inch longer. It was made of chromed plastic, had a
twist on/off switch, incandescent bulb, and was completely sealed.
There was no way to replace anything. You jes turned it on and waited
for it to come on. When new, that was about 5-10 secs. Later, it
became as long as a minute. Bottom line, owned and used that little
flashlight for almost 15 yrs before it finally launched its last
I used it hundreds of times and it was my always-there, always-works,
emergency flashlight and it did its job perfectly. At one point it
sat in a drawer, unused, for almost 5 yrs. Then I had a power outage
and coldn't find my main flashlight. I remembered my lil' space light,
dug it out, turned it on, and after about a minute, it came on,
almost bright as new. If I could find another one, I'd buy it in a
heartbeat. I've never seen another like it, since.
I bought a "shaker" LED flashlight in a dollar store for $3 thinking it was
a great deal,but it turned out it had two 3V lithium cells,a CR2032 and a
CR2012,the induction coil wires were not even connected,the "magnet" was a
piece of unmagnetized soft iron,and there was no storage capacitor on the
little circuit board.
did you know there are cylindrical sealed lead acid batteries?
I had a battery pack that comprised 6 of them to make 12V,they were F-sized
You can also buy Coleman camping lanterns at WalMart that have sealed lead
acid battery packs.
I have a number of those small LED flashlights that I got free
from Harbor Freight for visiting the store. They use three AAA
cells in series driving nine LEDs in parallel, with no current
limiting. When on, the drain from the AAA cells is about 160 ma.
As a retired engineer, I made up a little thingy about the
size of a dime which can be inserted in the back between the
battery terminal and the little spring. This inserts a 100 ohm
resistor in series with the AAA cells and drops the current drawn
to about 16 ma.
Since the current draw is 1/10 of an unmodified flashlight, the
AAA cells will last a bit longer than 10 times as long......
The light output is reduced, but not drastically so. All the LEDs
still light and the light output is more than enough to see your
way in a darkened room or read a book by.....
I have modified all my little LED flashlights this way, and all
work about the same.
My "thingy" is a piece of double sided G-10 with a small
1/4 , 100 ohm resistor put in a slot which connects one side
to the other. The shape is like a dime, so it will easily fit
right in behind the AAA cells in the back...
Just wanted to pass this along in case someone here would
like to try it...
Andy in Eureka, Texas
I have bought at least 9 led flashlights. Only a couple were reliable.
I always have to bang on them.
Those colored ones were the worst. The best which I use most often,
and also has a fairly warm light, I bought at Target, River Rock, and
of course, unavailable. I bought some from Deals Extreme and none
Very, very interesting. To understand how you built it, I'd
sure like to see some photos, maybe even on a "MACRO" setting.
Does seem to me that a dime is pretty thick for inserting behind
one of those AAA batteries.]
And, what's a G-10 (double sided)?
You say "right in behind the AAA cells" ie plural -- if they're
in series, all you need do is put it *somewhere* in the circuit,
ie behind any *one* of the cells? Or am I missing some basic
concept of what you've done?
Question: how did you measure the amps pulled? That is, where
and how did you break the circuit so you could insert the
ammeter (part of a vom)? At least in my 3-AAA led lights
and headlamps, it's a pretty tight fit.
Obviously you have some neat technique that I'd like to learn!
firstname.lastname@example.org (David Combs) wrote in
with new cells?
100 ohms seems like a lot,the math doesn't add up.
.16a x 100R = 16 volts drop.
maybe 10 ohms,or 1 ohm?
no,it goes between the internal 3 cell battery holder and the spring that
contacts the holder.
you can get .031" double-sided plated circuit board(plated on both
sides...),the good stuff is made of G-10 epoxy glass.
it's thinner than a dime. .062 (1/16") is about the same as a dime.
I buy mine at Skycraft Surplus,Orlando.
A SMD chip resistor would be about right.
(SMD is surface mount device;tiny.)
I think he put it in behind the battery holder and the end cap.
that's how I would do it. then it can't short the LED board.
DMM's (digital multimeter) are more accurate.
VOMs are the old analog meters,like a Simpson 260 or Triplett.
you take the flashlight's end cap off,and put your probe tips between the
center contact of the battery holder and the alum. case. I think the 200ma
range of a DMM has too much resistance and alters the current
flow,distorting the measurement.
Use the 20A range,or if your DMM has a 2000ma range,use that.
the higher the meter's current range,the lower it's internal resistance.
something you HAVE to consider for current measurements;
the meter's internal resistance.
for volts,the DMMs input R is usually 10 MegR,but the cheap HF DMMs are
only 1 MegR.
A VOM is rated ohms per volt,most VOMs are 20Kohms/volt,so a 10 volt range
is 200K ohms load on the circuit under test,and it goes up as the VOM range
is increased. A DMM is constant load resistance over all the volts ranges.
But current meter resistance changes with the range selected.
Ohm's Law R=E/I,so for a 200ma range,the DMM has 1 ohm resistance;the basic
DMM volts range being 200mv full scale.
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