Lux III Direct drive from alkalines?

I've been searching the archives for some time now and I'm fairly confident it's possible but I need some expert to give me the green light /ubbthreads/images/graemlins/smile.gif

I've got one of Hotbeams Hotlips with a TWOL Lux III on it, is it ok to direct drive it from 3 C alkaline cells? (4.5 volts total). I know I'll overdrive it a bit, and that would be ok if it doesn't break the led. (Lux3's are not available in the netherlands so I don't want it to die on me /ubbthreads/images/graemlins/smile.gif )

Thanks

I think you should be okay with that bin. I have made three SYOL binned lights that DD from 4 AA and they have been holding out okay. On fresh batteries, the voltage only dips to about 5.5v or so at 1.8 - 2A. Probably beats the light up a bit but once the batteries settle it drops down to about 1.6A. For more on the build take a look here. I think the key is to have a high vf like the L's and M's. If you want to be safe you can always add a little resistance.

TW0L DD on 3C alkalines will run just fine.

I've built DDs using a vf of "K" using 3 C 4500mah NiMh and I get about 1.5A when they are fresh off the charger. vf of "J" on 3C alkalines put you at 1.6A but doesn't stay there very long. vf of "J" on 3D alkalines however will get you 1.8A. "K" is the lowest I would go DD on 3D alkalines.

Got for it Fruitski /ubbthreads/images/graemlins/smile.gif

Ok I took that as a word from the master and went ahead, all I can say is WOOOOOOWWWWW
this thing is amazing!!! it's housed in a titanium 2D mag fed by 3 C alkalines, if i measured correct it's sucking 1.2 Amps.
It produces way more light than my 4d mag, and seems to be on par with my e2e in the ceiling bounce test but has a way smaller hotspot so it out throws the surefire easily.

this machine () is amazing, in fact it's the first LS I ever handled except for the 1 watt in the black diamond zenix. I love this stuff!!

btw any thought on runtimes for this config

Hotbeam: thanks for your great service! this really makes it easy for everybody to start playing with these little wonders

I have 2 ledlenser v2 powerchip lights that supposedly came with 1 watt emitters. I got these in January of 2004.
They are running fine with as much as 1.6 amps from 3 battlepack.com N cell nimh batteries.
A good heatsink seems to save the day for an overdriven luxeon emitter.

Could anybody give me an estimate on a supposed runtime or maybe give a trick to calculate it?

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FrUitSkI said:
Could anybody give me an estimate on a supposed runtime or maybe give a trick to calculate it?

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Sure, assuming your 1.2 Amp (1.8 Watt per cell) number is right, I bet it's bright.

As to run time on C cells, easy, go to say Duracell C cell specs and look up run time for that level. Maybe 25 minutes to .8 volts a cell, but a more realistic 1.2 per cell (no doubt kinda dim by then) is *under ten minutes*.

How much are you getting?

Doug Owen

Is there any difference in running 3C as opposed to 3D for the TWOL? And would an 1 watt R2H be overpowered by 3D?

3D has less internal resistance than 3C, as such the voltage drop due to the current is less than that from 3C. Because of this, the current flowing through the lux from 3D is greater than that from 3C. How much greater, i dunno the exact. But it is somewhat bigger.
As far as R2H concerned, i think it would be better to do the precaution and use resistor. R2H has low Vf and that might allow the 3D to pump a tremendous current through it. It might die fast /ubbthreads/images/graemlins/icon3.gif

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shiftd said:
As far as R2H concerned, i think it would be better to do the precaution and use resistor. R2H has low Vf and that might allow the 3D to pump a tremendous current through it. It might die fast /ubbthreads/images/graemlins/icon3.gif

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Shifter is right, I would definitely use a resistor for the R2H on 3Ds. I got way into 1.8A with a vf of "J".

Thanks, guys--can anyone direct me to a thread that describes how to do this? Is it a simple thing to do? I'm a bit new to this stuff.

You should be able to direct drive using nimh C cells using an L no problem as well. I direct drive my TWAK with no problem on 3 c nimh batteries, although I never do it when they are "fresh" off the charger, I always let them sit a few hours.

Direct driving a TWAK with 3 D nimh however, now you are treading thin ice /ubbthreads/images/graemlins/smile.gif although a TWOL might be able to handle it.

I do not have a problem direct driving my FC-3C with C NiMH's, and I believe it is a J Vf. Starts out high but settles down. I usually let the batteries settle down for a few hours off charger.

Bill