Battery Config for Driving the LuxIII

ResQTech

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How do I drive the LuxIII at or a little above spec with the following battery configs AND what will be the approximate runtimes of each? Please tell me which converter board or resistor to use if necessary.

1) 2 - D Cells - 3.0V
2) 2 - C Cells - 3.0V
3) 3 - C Cells - 4.5V
4) 2 - 123 Cells - 6.0V(Series)
5) 3 - 123 Cells - 9.0V(Series)
6) 6 - 123 Cells - 6.0V(3 parallel banks of 2 in series)

Thanks!!!
-ERiC
 

shiftd

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1) Need BB750, runtime about 7~9 hrs
2) Need BB750, runtime about 3~4 hrs
3) Need resistors, depending on the current, runtime is about 8 ~10 hrs
4) Need DB750, runtime about ~2 hrs
5) need DB750, runtime about 3~4 hrs
6) Need DB750, runtime about thrice #4

Assumption:
Vf = 3.47V
Efficiency ~ 80%
C capacity ~ 3500 - 4000 mAH
D capacity ~ 10000 mAH
123 capacity ~ 1350 mAH
current drive to lux3 is 750 (you can do higher, but less runtime of course /ubbthreads/images/graemlins/smile.gif )
 

jtice

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I thought you could do a 3C LuxIII direct drive?
Didnt someone direct frive a TWAK the other day?
I think there had been 3C and 3D direct drive TWAKS now.

I'm sure its driving them hard,,, but , thats what its all about ,, right?
 

MR Bulk

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[ QUOTE ]
jtice said:
I think there had been 3C and 3D direct drive TWAKS now.

I'm sure its driving them hard,,,

[/ QUOTE ]


Ticey,

I think the term "hard" is relative. They used to think an LGI running at 4.5V/900mA into a 1W (which was then spec'd at 350mA) was driving it too hard, yet now we have the Luxeon III with one of its recommended published specs set even slightly higher (1 amp), with no real difference in the Luxeon itself except perhaps better thermal management internally.

We CPF'ers push the envelope! Somebody should go with FOUR C's or D's!

/ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif

Just kidding, just kidding -- it probably won't work -- but waitaminute, it IS a Luxeon THREE, ain't it...?
 

ubermensch

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Right. I can be done--we have the technology. . . Isn't it only like 900mA tops on direct drive though? Can someone verify that. That isn't overdriving, that's just plain driving. jtice, by the way, isn't that a Cam De Leon eyeball?
 

ledlurker

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For 3C and 3D configurations a .75 5 watt resistor will restrict the current to around the 1000 to 1100 ma amp range. Direct drive on 3c and 3D will run around 1.4 to 1.5 amps. I have yet to see a test done to seen the current limit is on the Lux III vrs. brightness and you start wasting your excess power in heat.

D will must a little more current than C's due to the difference in internal battery resistance. I am awaiting by first batch of TWAK and AA Epoxy to try this mod.

I think the 3C lights are perfect for pocketable walking lights at night.
 

jtice

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[ QUOTE ]
ubermensch said:
Right. I can be done--we have the technology. . . Isn't it only like 900mA tops on direct drive though? Can someone verify that. That isn't overdriving, that's just plain driving. jtice, by the way, isn't that a Cam De Leon eyeball?

[/ QUOTE ]

uber,

Its an eyeball from the band TOOL.
I have no idea what you said. lol /ubbthreads/images/graemlins/icon3.gif
Please enlighten me.
 

Sway

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I'm running 2x123 DD into a LuxIII TWAK right now and it's holding up well, still on it's first feeding of 123's. Time will tell /ubbthreads/images/graemlins/popcorn.gif
 

hotbeam

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Sway... that's a lot of juice you are feeding those poor lil' LIIIs /ubbthreads/images/graemlins/grin.gif
 

MR Bulk

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Sway,

Ooh, interesting. Boils muh blood, this overdriving thang!

I used two 123s on a 1W (in the "Shorty LGI") and it eventually failed as did one (and Only one) I sent to shiftd who took it with full knowledge of the drivetrain. But this was after a rather long (months?) time over numerous intermittent activations. Mebbe the Lux III's will prove us wrong -- I am hoping. Sucker must be bright, eh? I know the 1W's were...
 

Sway

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Mr.B

I have a TWAK'd 3D from the same reel I'm using as a control; both are using Howard’s HotLips. I took beginning beams shots and the 2x123 is brighter and throws better I’m curious what it will look like after it has digested several sets of batteries, if it lives that long?

I have been using it just about every night for the last week making outdoor beam shots with spotlights as I would normally use my Arc LSH-P for setting up and finding my way around so it’s getting more use than normal.

I will post my findings /ubbthreads/images/graemlins/thumbsup.gif

Later
Sway
 

kj

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Sway seems to have a good result and I know AilSnail is also running III with 2x123 in DD, but my results with 2x123 DD was disappointing.

I tried 2x123 DD with SY0L / TV1L on McLux PR head and posted my finding in this thread. In sum, SY0L was died in a few minutes. TV1L worked more than a few minutes but interestingly it was dimmer than the one driven by DB1500. I stopped using this config after getting the lux reading, so I don't know how long it would last.

Maybe there were heat dispension problems, but not sure. I want to see other examples /ubbthreads/images/graemlins/smile.gif
 

evan9162

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2x123 direct drive is probably driving the L3 at 2+ amps (maybe even 3). You simply drive the luxeon into the ground.
 

ResQTech

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So is there a resistor you can put in to get the current down to acceptable levels? Will the resistor waste a lot of power?
 
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