Small LED flashlights.

[W. eWatson]

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

 

[Jim Thompson]

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

Probably the contacts at the ends of the battery holder. I sometimes
use an ink eraser to scrub such contacts clean. They may also need to
be bent outward... maybe some their "springiness" has been lost.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[John Larkin]

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson" <wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The problem is the $2 price. The internal construction, especially the on/off
switch, is usually ghastly.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation

 

[Jim Thompson]

On Sat, 19 Apr 2014 11:25:52 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson" <wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The problem is the $2 price. The internal construction, especially the on/off
switch, is usually ghastly.

Often, there is _no_ on-off switch, just twist to compress the
contacts against the battery stack.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[W. eWatson]

On 4/19/2014 11:32 AM, Jim Thompson wrote:

On Sat, 19 Apr 2014 11:25:52 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson" <wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The problem is the $2 price. The internal construction, especially the on/off
switch, is usually ghastly.

Often, there is _no_ on-off switch, just twist to compress the
contacts against the battery stack.

...Jim Thompson

The on/off mechanism is at the back of the flashlight. It's a push
arrangement. I guess there's a spring inside it.

 

[Michael Black]

On Sat, 19 Apr 2014, W. eWatson wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to shake
or knock them against something like the palm of my hand to get them to
produce the light again. What's the source of the problem? batteries in their
holders? The 8 or so LEDs that provide the light?

For a long time I assumed it was bad contact between the batteries and
ther est (especially since the 3AA or 3AAA ones I've had all had a battery
holder that relied on pressure to keep good contact).

But, I recently needed some white LEDs so I grabbed a 99cent LED
flashlight from the store, and immediatley took it apart.

I guess one side of each LED was soldered together, but the other leads
were just twisted together and relied on pressure to make contact. So
it's just that the flashlights are badly put together.

This may account for the missing LEDs on some. I've bought various kinds,
and on some, some of the LEDs don't light. My original thoguht there was
that they were bad to begin with, but now I suspect they are fine, but
just not making contact.

I wsa given a more expensive LED flashlight, that comes with a clamp, and
I guess the LEDs are Cree. Big difference. If nothing else, it uses one
LED per mode (it had a few), and is as bright as one of the cheaper LED
flashlights that have a lot more LEDs.

So if you have a problem, take it apart, and tighten it, maybe figure out
how to solder it altogether before putting it back together. I know one
LED flashlight became more reliable when I tigtened the led area (for some
reason taht area could be screwed in, so I screwed it tighter).

Michael

 

[Michael Black]

On Sat, 19 Apr 2014, John Larkin wrote:

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson" <wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The problem is the $2 price. The internal construction, especially the on/off
switch, is usually ghastly.

TO be fair, I bought an LED adapter for my 2AA Maglite, and it too stopped
being reliable. Once I figure out where I put it, I hope to use some more
recent information about taking the flashlight apart to clean up the
contacts in the Maglite.

Michael

 

[Maynard A. Philbrook Jr.]

In article <liueo7$gkv$1@dont-email.me>, wolftracks@invalid.com says...

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

Read that!

http://en.wikipedia.org/wiki/Galvanic_corrosion

Jamie

 

[Bob Masta]

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

I also have a number of these, including some free Harbor
Freight models. I've had a couple where the problem was at
the *front* end, not the switch end. Seems the lens holds
the whole mess together and provides contact pressure for
the guts. But it isn't held in very well (no separate
retaining ring) and it can come loose.

Try pressing in on the lens when the light stops working.
If that brings it back, take the batteries out to relieve
the pressure on the lens, press it in, and apply a thin bead
of epoxy to make a retaining ring. Worked for me!

Best regards,




Bob Masta

DAQARTA v7.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusiq generator
Science with your sound card!

 

[default]

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The quality of the product. Spend some money and you may get a decent
product or be cheap and frustrated. Them's the choices.

For the cheap ones, I end up hard wiring the little 3AA holders to the
contacts, and spraying the switches with WD40, then they last awhile.
Once the contact springs for the battery cells start to corrode, its
the end of life for those things.

I've got one that has the name "Darcy" on it. Cost ~$16. Works
blindingly well, is waterproof, floats (important in a waterproof
product IMO) and can really be knocked around and just keeps working.

 

[Michael Black]

On Sun, 20 Apr 2014, default wrote:

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The quality of the product. Spend some money and you may get a decent
product or be cheap and frustrated. Them's the choices.

For the cheap ones, I end up hard wiring the little 3AA holders to the
contacts, and spraying the switches with WD40, then they last awhile.
Once the contact springs for the battery cells start to corrode, its
the end of life for those things.

I've got one that has the name "Darcy" on it. Cost ~$16. Works
blindingly well, is waterproof, floats (important in a waterproof
product IMO) and can really be knocked around and just keeps working.

I have a few of those, but paid no more than five dollars. And one of
them is now out of service, the end that you screw in over the batteries
split, so it would no longer stay in place. I seem to recall having to
whack them every so often, but then it's important to remember that
flashlight whacking began in the days of flahslights with incandescent
bulbs.

Michael

 

[Shaun]

"Jim Thompson" wrote in message
news:fmf5l9pihak8vhr542jdg6vr2soiarni52@4ax.com...

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

Probably the contacts at the ends of the battery holder. I sometimes
use an ink eraser to scrub such contacts clean. They may also need to
be bent outward... maybe some their "springiness" has been lost.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.


Jim you IDIOT!!! Erasers have a glue like substance in them to hold the
eraser together, that can stay on the contacts that you're scrubbing. DO
NOT USE AN ERASER!
A cotton swab with contact cleaner on it does a good job to remove a little
tarnish. While your at it clean all the contacts this way and the battery
terminals, it all makes a difference!

Shaun

 

[default]

On Sun, 20 Apr 2014 17:19:50 -0400, Michael Black <et472@ncf.ca>
wrote:

On Sun, 20 Apr 2014, default wrote:

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The quality of the product. Spend some money and you may get a decent
product or be cheap and frustrated. Them's the choices.

For the cheap ones, I end up hard wiring the little 3AA holders to the
contacts, and spraying the switches with WD40, then they last awhile.
Once the contact springs for the battery cells start to corrode, its
the end of life for those things.

I've got one that has the name "Darcy" on it. Cost ~$16. Works
blindingly well, is waterproof, floats (important in a waterproof
product IMO) and can really be knocked around and just keeps working.

I have a few of those, but paid no more than five dollars. And one of
them is now out of service, the end that you screw in over the batteries
split, so it would no longer stay in place. I seem to recall having to
whack them every so often, but then it's important to remember that
flashlight whacking began in the days of flahslights with incandescent
bulbs.

Michael

Yeah, I just looked them up and the price is lower than what I paid.
Mine is an old one but they still make that model.

Ditto the whacking. I think we tend to forget how really bad some of
the old incandescent flashlights were. But then it ain't rocket
science and it should be possible to get a long lasting flashlight for
a reasonable price - it isn't like there's a ton of money in the
component parts.

 

[whit3rd]

On Saturday, April 19, 2014 11:19:49 AM UTC-7, W. eWatson wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something...

It's probably the (transparent) oxide layer on the aluminum parts.
Tinned steel and copper are compatible materials, but the
interface to aluminum can grow tough, transparent oxide.
Spring contacts, battery terminals, LED wires, switch all are
tin/copper. The case carries current, it's aluminum (painted
or anodized, even).

Remember the reliability issues about aluminum house wiring?

 

[David Eather]

On Fri, 25 Apr 2014 12:08:36 +1000, David Eather <eather@tpg.com.au> wrote:

On Sun, 20 Apr 2014 04:19:49 +1000, W. eWatson <wolftracks@invalid.com
wrote:

I have several small LED flashlights. They are 3-4" long and about 1"
in diameter. They sell for about $2.00. Often they go out, and I have
to shake or knock them against something like the palm of my hand to
get them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

Cheap torches don't have separate spring contacts - they make do by
using the PCB for the led regulator. Remove the battery and have a look
- the most common problem is the lump of solder that makes contact with
the case is no longer doing it's job. Take the board out, add more
solder and push the solder over to whatever area has the best chance of
working - problem mostly solved!

 

[amdx]

On 4/19/2014 1:25 PM, John Larkin wrote:

On Sat, 19 Apr 2014 11:19:49 -0700, "W. eWatson" <wolftracks@invalid.com> wrote:

I have several small LED flashlights. They are 3-4" long and about 1" in
diameter. They sell for about $2.00. Often they go out, and I have to
shake or knock them against something like the palm of my hand to get
them to produce the light again. What's the source of the problem?
batteries in their holders? The 8 or so LEDs that provide the light?

The problem is the $2 price. The internal construction, especially the on/off
switch, is usually ghastly.

For Christmas my daughter got me one of the Kobalt flashlights that
comes with the (useless to me) snake neck. I really like the flashlight,
it has a convenient plug built in for recharging, the lens is adjustable
for tight or wide light dispersion, and it has magnets built in so I can
stick it to a metal cabinet. I never knew I needed a flashlight so much
until I had a good one. I saw them on sale a Lowes recently for $19.95,
I was disappointed, I think my daughter spent full
price of $39.95, that's to much.
Mikek