Hi everyone! Some non scientific observations on a LED flashlight.<br><br>I had received a Dorcy brand 'Coolblue' waterproof flahlight that was purchased at wallmart for about $8. It is a single focused LED flashlight running on 4 AA batteries. It claims to be waterproof, floats, and runs for 200 hours on one set of AA cells. I have not put that to the test yet. <br><br>Being one of those folks who if it can be dissasembled takes it apart I discovered this. The LED is mounted in a standard flashlight bulb base. Being an experimenter I thought to try it in my 3 D cell Mag-Lite. I use it around the house for power outs and such. It is my policy to change out the batteries for fresh ones each year after the first of the year, needed or not, so they are always ready. It worked fine.<br><br>This led me to do an experiment. Before I changed the batteries I thought I would see how long they would last in the 3D Mag-Lite with the LED bulb in place of the regular bulb. Well......<br><br>I turned it on Jan 2, 2002. It has run 24/7 since then (7 weeks and counting!) The light output has dropped aproximatly 25% over this time. It is now getting to be a challenge to see how long it can go before it finally dies. The batteries are Rayovac alkaline D cells. <br><br>If you are looking for a long term light source you might want to consider something like this. The light output is not as bright as the original bulb but more than enough for most uses. It is still plenty bright for me to read by easily, even now. If you remove the reflector head and put it uprite like a candle it will light the room, not like a 60 watt bulb by any means, but enough to reasonably see by.<br>Like I said nothing scientific but thought I would pass along my observations.<br><br>Enjoy life, Mike Mc