Feb. 24th, 2004, By Steve KB1DIG & Kim KB1GTR



Emergency Power operation is becoming more commonplace, with a few different good ways available to accomplish this goal.   We decided some time ago, to go with 12v/DC battery backup power.  Several Hams spend a lot of time preparing to run their equipment during a blackout.  There does not seem to be a lot of information out on station lighting.  We observed normal incandescent or even fluorescent lighting can greatly increase the drain of battery backup systems.  A single 5Watt Halogen 12v/DC bulb runs @ 400mA, and produces a lot of light.  This Jumbo LED runs at only @ 40mA, with less light produced, but still a fair amount.  2 or 3 of these LEDs seems to do the trick at this QTH.  Enough lighting to work with and a lot less overall power drain..  The Energy Efficiency of the LED is truly worth your time exploring.  Summary information is presented along with our recommendations regarding implementation.  Please send us your ides too.
First off.  Click on the images below for more close-ups of these 10mm Jumbo LEDs.
Fun stuff!  Found these on e-Bay for a little over $1.25 each, including shipping.  Included were the 270 Ohm (5% Tolerance) resistors needed, and even pre-cut sections of shrink tubing.  What a deal!  Ebay can be a little confusing sometimes, but an interesting place to find stuff.  The 8mm or 10mm sizes we found have the same high light intensity @10,000 mcd .  9v to 13.8v/DC range with the resistor soldered to the positive leg of the diode.  In the 3 images above, the positive side of the diode is on the left.  The "positive-side" is called the "Anode".  The "negative-side" is called the "Cathode".  Several others sources for LEDs are out there too.  Please check with your vendor to determine the correct value resistor needed, and the positive or negative side of the diode, before assembly.  For polarity, a simple low-voltage continuity test will also accomplish this.  With diodes the DC voltage will only flow positive to negative.  Be careful.  These LEDs we used only operate @ 4v/DC-max without the resistor in-line.  Over-voltage can damage them.

One of the biggest benefits of LED lighting:  Unlike normal lightbulbs, LEDs will last thousands and thousands of hours.  Tough little buggers.. They very rarely burn out!
Links to related topics:
Everything you ever wanted to Know about LEDs, but were afraid to ask! 
LED Circuitry tutorial: how to hook up LEDs
Building an LED caselight
How to read Resistor Color Codes
Big  Brown Rabbits Often Yield Great Big Vocal Groans When Gingerly Slapped??

A few different assembly ideas.  Should be self explanatory... 
Click on the images for larger views.

Some other shots taken.  Some were in the dark and gives a rough idea.. 
Also, click on images below for larger views.
This was with the camera flash on.
This was taken in total darkness.
These were with just 1 LED from an above angle, at about a 3 foot distance. Real life was a little brighter than these images.
Same single LED, about 10 inches away from the surface.
Single LED now at about 2 feet away..
Ended up building a new semi-portable 12v/DC station-power setup with a Type-29 Deep-Cycle Marine Battery.  The Kenwood rig is a little power hungry.  Current drain is about 2.5A just in standby mode.  Every mA/h saved means a little more air-time in the long-run....LED lighting should help.

And...Remember that 12V cigarette lighter socket mounted on the Comm-Box?


Have a suggestion?
Steve KD6LAJ:Led lighting for low current emergency
Hi, You have got a lot of good ideas, so here is another for your LED light page.

Your 270 ohm resistor is using more energy than your LED!  If you put 2 LEDs in series, and change the resistor to about 150 ohms or so, you will use the same current from your battery and get twice the light.  (3 LEDs in series makes the brightness very sensitive to the supply voltage, so 2 seems to be the best compromise.)  Cost is higher for 2 LEDs, but twice the light for no more current is worth it....

Steve KD6LAJ

Rex AA1KL: ....The main web page for viewing items and sending for the catalog is: They have several useful lighting options and lots of other neat gadgets, the two lighting option I was noting are:

Need an extra light in your car? Plug this flexible LED light into your car’s 12V cigarette lighter socket and illuminate the interior in any direction you want! 

• Integrated DC 12V cigarette lighter adapter 
• Power-saving bright white LED never needs replacing 
• Includes fuse protection 
• Flexible neck holds its position 


This super bright hands free LED light projects a beam of light in almost any direction! The handy clip has soft rubber feet to securely grip to just about anything and an adjustable swivel mount provides 360 degree positioning to help you zero in on hard-to-light areas. 

• Bulb never needs replacing 
• Waterproof 
• Includes 2 x 3V lithium batteries 
• Extra long battery life 
• Swivel mount points light in nearly any direction 
• Clip opens to 1-1/4" wide to clip onto most surfaces 

There is also a variety of USB powered lamps. 142 0372, 142 0350, and 142 0374 ......

.... I agree with the 12v cig lighter or even Anderson powerpole connectors. Enclosures with reflectors would be an issue. I bought four of those little lights. The two lights seem to draw 40 to 50 mA.  The battery from one company (energizer) is 225 mah...So, at most 9 hours per set of batteries....

Rex G. Carr, M.D.
NHARES EC Southern Grafton
VTARES AEC Windsor County

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