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Extended Life 6V LED flashlight  RSS feed

 
Erik Little
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Location: USDA 5b - Central IL
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So I found a 99 cent amazon ebook that showed me how to add a 150 ohm 1/2 watt resistor to a 6V Eveready flashlight and it would make it last 2000 hours. I have completed the modification, it was relatively simple, removed 1 red wire and put resistor in its place and soldered the resistor to the metal contacts.

Without a light tester, like what photographers use, I am looking for suggestions on how to test the output.

One thought is to setup a piece of paper say 2ft from the flashlight and mark the broad area of the beam and the focused area of the beam and monitor these areas until there is a visible change.

Any other suggestions?

I will make a vid of the flashlight and the modification that was done to it.
 
R Scott
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I have little faith in paper tests, with or without a light meter. They are like horsepower or top speed numbers for a car--cool number but not relevant to my life. I would do a side-by-side test of an unmodified and modified like YOU would use it in real life. Is it still bright enough? If so, SUCCESS.
 
Erik Little
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I also have the 4 D Cell adapter and wanted to put in some NiMH D cell rechargeable batteries to see how long it would run. I might just do a run time test for the regular batter vs NiMH and an unmodified flashlight.

Any other ideas out there.
 
Erik Little
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My test has been running since Friday at 3pm using the modification and a 6V alkaline battery.
 
K Nelfson
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Unless there's a boost circuit, flashlights, LED or incadescent, just run down slowly. For me, it's a real irritation because you don't know how bright or dim the light is ever. In real-life conditions, it's not always apparent how bright the light should be and the slow decay of the battery is hard to detect. If you can, find a flashlight that uses 1-2 batteries because then there's a better chance that there's a boost circuit in there.

http://en.wikipedia.org/wiki/DC-to-DC_converter

Back to the original post---use your camera in manual mode as your light meter. And obviously, lowering the current through the LED will use less energy. But with LED flashlights, the usual issue is getting it bright enough to be useful.
 
Erik Little
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12/2 Still Running. 22+ days so far. 528+ hours of continuous run time.

In a power outage some light is better than no light. Sometimes all you need is a little bit of light...you may not need a spot light.
 
allen lumley
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E Little : You may be interested in playing with a joule thief, a good place to see several of the simpler projects is at Instructables.com Big AL !
 
Cris Bessette
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allen lumley wrote: E Little : You may be interested in playing with a joule thief, a good place to see several of the simpler projects is at Instructables.com Big AL !



I got into building those a few months ago. The useful thing about the joule thief is that you can run a 3v white led on a 1.5v battery until its almost dead.
If you have a flash light that holds more than a few batteries then I think the joule thief wouldn't really serve a purpose.
 
Cris Bessette
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E Little wrote:So I found a 99 cent amazon ebook that showed me how to add a 150 ohm 1/2 watt resistor to a 6V Eveready flashlight and it would make it last 2000 hours. I have completed the modification, it was relatively simple, removed 1 red wire and put resistor in its place and soldered the resistor to the metal contacts.


I will make a vid of the flashlight and the modification that was done to it.



If the resistor is connected between the LED and the batteries, it is reducing the current to the LED. Since the LED is using less power and it is producing less light,
the batteries would obviously last longer.

To me, what might be more useful is to install a switch across the resistor, so you can bypass it when you need brighter light at times.


 
Erik Little
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Location: USDA 5b - Central IL
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Cris Bessette wrote:

If the resistor is connected between the LED and the batteries, it is reducing the current to the LED. Since the LED is using less power and it is producing less light,
the batteries would obviously last longer.

To me, what might be more useful is to install a switch across the resistor, so you can bypass it when you need brighter light at times.




Well if I figure out a way to do that on this flashlight I might try it. I mainly wanted to see how long it would run with this modification.

It has been running since 11/8 @ 3pm.

720 hours of continuous run time so far.
 
Erik Little
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1,917 hours of continuous runtime and still going. It is not as bright as it was when I first turned it on but that is too be expected. I will try this with rechargeable batteries after I hit 2000 hours.
 
Erik Little
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2,184 hours of continuous runtime!!!


I will post some pics of the modification soon.
 
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