Modders: Q5 direct drive question

webley445

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I have a dereelight module that got fried. So I rigged it to run direct off of two CR123's.
Man it is bright! Blows my Fenix P3D Q5 on turbo into the dust!

But what now/ What will be the long term repercussions of doing this?
 

TigerhawkT3

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Lifetime of the LED will go WAY down. How far, I don't know, but I wouldn't rely on it. You should probably put a resistor in there (3, maybe 5Ω).
 

mmmflashlights

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Nothing wrong with direct driving an LED, at a reasonable voltage that is.... Direct driven off of 2 Lithium Primaries with a total voltage of over 6 volts and not a lot of voltage sag, now that's a very bad idea on the other hand. You'll probably damage the LED within minutes.
 
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webley445

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Will the resistor diminish output?


Some quick pics:

Dereelight Mod

2535034387_e04dfb280d_o.jpg


P3D Q5 Premium onTurbo

2535034383_264c5b701b_o.jpg
 
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mmmflashlights

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Yes, and how much it drops it depends on the resistor used.

I would buy a cheap circuit from DX or KD, gain regulated output, multiple modes, etc.
 

Gunner12

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But the LED will be overdriven at the start of the runtime(less then it is now though, with a 18650).

I'm surprised that the LED didn't burn out, but then batteries do have an internal resistance.
 

TigerhawkT3

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With the CR123As, current probably didn't go above 2.5A or so, since that's pretty much their limit. The Li-Ion is a more acceptable choice, but still overdriving a bit, especially with a fresh cell. With good heatsinking, heat damage and lifetime reduction should be minimal.
 

Superdave

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I had an ebay Q5 P60 drop in on the bench the other day, @ 9V input (to the regulator) the Q5 was seeing about 3.3V and total draw was about .5A

LED's need some kind of current limiting, even 1 resistor in series would help it last a bit longer.


BTW, a Q5 direct driven in a AA-Mag will last for a very long time... not very bright though. :rolleyes:
 

Nitroz

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I have a dereelight module that got fried. So I rigged it to run direct off of two CR123's.
Man it is bright! Blows my Fenix P3D Q5 on turbo into the dust!

But what now/ What will be the long term repercussions of doing this?

You're just asking to let out the magic smoke.:poof:
 
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