# 1st post, LED life question



## Stu-Pidaso (Nov 13, 2011)

Hope I picked the right section. 

I have a project I have been working on for my daughter that requires bright lighting with very little room for power. I am making a video game prop from the game called Bioshock and the prop is called an Adam Syringe. Part of the prop requires a liquid to be lit up. I have a plastic bottle that I have placed colored hair gel in. I then took an empty, translucent highlighter marker body with the smaller end sealed and shoved into the bottle. The outside diameter of the marker and the inside diameter of the bottle opening matched thus creating a seal. The bigger end of the marker body is open and I can put anything in it as long as it fits. 

Now here is where I have started having problems. My first attempt at lighting the bottle I used one of these cheap flashlights I found in CVS that take 3 AAA batteries. By the way I am using that battery holder so that is the voltage. I disassembled the light and hot glued the LED base to the bottle/opening. After a few hours of use the light began to flicker. I thought it might be a fluke so I tried it with another flashlight and got the same results once again after a few hours. I noticed that it was not all the LEDs but rather just a couple. I then tried another flashlight assembly that took the same voltage but was a single LED this time. Once again after a few hours the darned thing starts blinking again as if it is going bad.

Any idea what I use that would keep this from happening? Below is a video of the prop I am working on.


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## Norm (Nov 13, 2011)

:welcome:

Moved to Special Application Lighting. - Norm


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## StarHalo (Nov 13, 2011)

_In the garden we are growin',
many changes will be flowin'.
If you wanna be amazin'
see the flowers we are raisin'!_

Cheap LEDs are not known for their longevity; I'd go with a few LEDs from Radio Shack and just wire them up to a battery holder. Also, there's the possibility that your glue might have a wee bit of conductivity to it, you might try some other method of attaching them (gluing the LED dome itself, as opposed to the leads, is an option)


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## Stu-Pidaso (Nov 13, 2011)

Thanks guys. From what I can tell online and from an ohm meter Hot glue does not look to be conductive. 

I was not sure if this was a heat issue as I have seen post about heat from LEDs but yet read stories about LED traffic lights not having enough heat to melt snow.

I don't mind buying LEDs from Radio Shack and soldering but I have no idea what I am looking for when it comes to specs about brightness. I do know of course the battery holder give me 4.5 volts.


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## StarHalo (Nov 14, 2011)

It's very rare you can connect an LED directly to a battery and have the correct voltage; you'll need to note the forward voltage rating on the packaging and then use a resistor to achieve that number. If you were previously wiring your LEDs directly to your power supply without a resistor, that's probably what killed them.


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## Stu-Pidaso (Nov 14, 2011)

StarHalo said:


> It's very rare you can connect an LED directly to a battery and have the correct voltage; you'll need to note the forward voltage rating on the packaging and then use a resistor to achieve that number. If you were previously wiring your LEDs directly to your power supply without a resistor, that's probably what killed them.



Okay, now you got me thinking. Since the LEDs came out of the flashlight that the same battery pack did I am wondering if the switch has some sort of built in resistor. The switch on the flashlight was not used in my project. I will check that out and report back with my results.


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## Stu-Pidaso (Nov 18, 2011)

Hooked up a volt meter to the battery pack only and then with it in the flashlight body with the power running through the switch and saw no difference in voltage.


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