Need help w/ an LED in a 4AAA doublebarrel!

[Bad Influence]

Here's the scoop: I have a 4xAAA energizer DB wired for series. I installed a near-UV LED that I pilfered out of some stupid auto accesory. I had 2 of these LEDs, but fried the 1st one running 4 cells in series (almost had a F.E.D.) so I cut down to 3 cells with a "dummy" in one barrel. Now, I had some (estimated) half-used alkalines in it and the LED lit somewhat dim. Last night I filled it w/ fresh alkalines (still 3 cell) and now the LED flashes like a strobe light, and I swear the dang thing gets warm after about 30 seconds of usage. My guess is that it needs to be resistored down. As cool as a "black" light strobe looks, it's not too useful. Would I be correct in this assumption? If so, what resistors should I try?

Thanks!!!

 

[WayneM]

As we say down here - I believe you got a problem, buddy.

Yes you definitely need a resistor. You are probably drawing over 100 mA, and you won't have an LED for very long like that.

I would probably try a 1/4 watt 5% 43 ohm resistor, and then you might want to consider putting it in a dummy AAA cell.

 

[Bad Influence]

Oops! too late, turned it on for about 5 seconds, and fried the LED again.... D'OH!


Update! Saturday, went to RS and bought some resistors, 22, 44 & 68 ohm (I believe) Tried the 44ohm, and it ran for about 10 seconds, and started to flicker, so I shut it down. Reassembled w/ a 68ohm in a dummy cell, and bingo! Now I have a nearly useless near-UV torch. (Looks cool though) Also, put a dab of my glow-paint under the LED, and now the inside of the bezel glows a dim (but easily noticable) green after you shut it off.... very cool.

 

[WayneM]

Since you burned it up, I'm glad you burned it up on your own. I made a mistake and ran the numbers on 3 cells, rather than 4. With 4, 120 ohms would give you about 20mA with a 3.6 volt forward drop on the LED.

 

[machspass]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by WayneM:
Ask me about me doublebarrels - please.<HR></BLOCKQUOTE>

Ok, I'll bite. What about your double barrels, Wayne? Do you have suggestions for mods to them, or do you sell modified double barrels? I have a 4AA double barrel that I want to retro-fit with an LS. Any suggestions?

 

[lambda]

machspass,

You can look at how I made this DB AA mod on my old mod page at http://lambda10.tripod.com/

It still works, and is pretty bright.

 

[Tater Rocket]

I think his suggestion would be that you buy one of his 6AA or 8AA double barrels. IIRC, he is the one that has like a hundred or something, lol.

Spud

 

[lambda]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tater Rocket:
I think his suggestion would be that you buy one of his 6AA or 8AA double barrels. IIRC, he is the one that has like a hundred or something, lol.

Spud<HR></BLOCKQUOTE>

Nope, this be the only DB AA I have, and it's mine........

 

[WayneM]

No. I'm the sap that bought >100 Doublebarrels (mostly 8AA, some 6AA), and haven't modded a single one. However, I'm open to suggestions for mods, and will gladly part with some at a good price.