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9 Volt "Back-Up"

2 leds, using a 100 ohm resistor to regulate the voltage to prevent them getting burned out will allow them to keep lit in excess of 2 WEEKS!!

This makes a great back-up/emergency light for camping or power outages. Runs seemingly forever, compact, easily stored or carried. I added the clip to allow the light to be hung up above or placed in a position to shine where you want it to. You could even clip it to your shirt or pants. You can leave some laying around for when you need them in ziplock baggies with a 9 volt battery to keep out moisture. I have also used empty pill bottles that prescriptions came in to store them. If the bottle is the right size, the 9 volt will fit in there also. You can plug in the light and drop the whole assembly into the bottle for a candle glow effect. In the above example I super glued a refector and bezel from a Mini-Mag Lite together so it wouldn't fall apart, bored out the hole for the bulb so that an led would fit properly, and glued the led into the assembly. The lens helps to create a perfect circle of light, producing a bright center spot with a dimmer outer ring characteristic of normal flashlights and the beams they produce. See the photos below.

As a side note, the topic of hot spots, beams, and dim outer rings are a hot bed for flashlight afficianados. We are always in search of the units that produce the best beam and spots and....well, don't get me started. I think you get the drift. Photos of lights shining on walls or various objects are refered to as "beam shots" by us "flashaholics" and you'll find plenty at the candlepowerforums site.

I have made a few of these little toys, some using one led, or others using two, like the one above. I took one of the double setups and plugged it into a fresh 9 volt alkaline battery. I left it sitting on my bathroom counter to use as a night light for those early morning pit stops. It took three days before I could notice any dimming of the light. Another three days and there was more noticeable dim, but still plenty of light to see by. I could clearly make out the toilet with all the lights out in the middle of the night, so there were no "accidents" during that first week. It seemed that every couple of days the light would dim to a point that it was noticeable to my eye. When it was all said and done, and I had reached the end of my test period, the light was very dim [compared to when I started with a fresh battery]. But there was enough light that I could see my feet clearly, though dimmly, when holding the light at waist level. I could read the printing on the toothpaste tube by holding the light 3-4 inches away from the surface I was trying to read. The total time that the light ran ,continuosly, non-stop with no rest, meaning a constant drain on the battery, was an amazing 2 weeks and 5 days.

Now keep in mind there are those who use light meters and other equipment to get exact measurements of light output, so I'm only going by eye. Also human perception can vary day to day so my tests are informal and considered inconclusive to some.

Now think about it, over two weeks of continuos run time. So how long would that battery last with intermitten use? All told that thing ran for: 19 days X 24 hours = 456 hours. So even figuring just 2 weeks of very useful light, you're talking 336 hours. If you used the light for only 4 hours a night it would last you 84 nights! Do you see what I'm getting at? If there was a power outage or you were lost in a cave you would be able to see in the dark for a really long time. They should have given lights like this to those miners that were trapped. And I think this light would be great for those hard core hikers and campers that like to travel on foot and keep the weight of their equipment to a minimum. I love these little babies.

Looking down the barrel of the big gun.

Beam Shots

This is the 2 led set up. Light is 60" from the wall and the spot is about 2 ft. wide.

Here is the 1 led. It is not as bright, but the attached lens forms a nice spot and makes the outer ring brighter.

These shots are of the lights resting on the back of a chair shining on the wall from 18" distance. I wanted to show what effect the lens had when placed on the single led set up. the center spots are about the same, but as you can see the lens [on the left] forms a really nice round circle that, in my opinion, helps to smooth put the light. The 2 led is on the right, it is brighter, but the light "spills" out less efficiently than with a reflector attached.