LS Brinkmann 3AA mod question

tygger

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i want to convert a 3AA Brinkmann into a LS. do i need a resistor and a regulator? or is it okay to just go with a resistor and not worry about it? has anyone done this exact mod? i've checked out lots of CPF members mod pages and haven't seen this one done yet. this would be my first LS project so i wouldn't mind seeing how someone else did it. to me battery life is a little more important than brightness. anyone know the internal resistance of 3AA's?
 

Daniel Ramsey

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Now I actually regret deleting the 500 posts I made, if there is one particular flashlight brand that I am intimately familiar with its the Brinkmann Legend, there is a member here that bought one of my 3AA (yes thats three AA) Luxeon Legend mods, I used a 2.2ohm resistor, try a 2 and then a 1ohm for better light output, it will still only be 75% as bright as Lambdas 2AA mods.
 

tygger

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thanks daniel. yeah, sure would love to have lambda's mod. but since i've got a 3AA might as well do something with it.
 

Klaus

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Uh-Oh - Daniel,

"it will still only be 75% as bright as Lambdas 2AA mods."

any valid reasons driving the LS at the same current / voltage should result in different output (both heatsinked as well) ?

Hint - IMO pulsing is no valid reason if you compare the "average" current of the pulsed circuit against the steady one from three cells resistored to the same current
grin.gif


Klaus
 

Daniel Ramsey

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I have direct driven a Luxeon on 3 AA's but lambdas impulse driver pumps more out of the batteries, whats an average AA, 1100mA? with his driver and the luxeon on continuously it runs for two hours (average battery) so my guess is he is charge pumping/cycling the impulses at about 550mA. Which an average luxeon can handle peak forward pulses of 500mA I believe on the data sheet, and also Lumileds states a what, 10% give-or-take on their figures? So its all roughly whithin specs, no witchcraft, no alien devices
grin.gif
 

Klaus

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Daniel,

I think your math is wrong - you can´t compare the current to the Luxeons (which BTW is aprox. 400ma according to I think Lambda himself) at 3.3V or so to the current from the cells which are obviuosly much lower under load - plus you forgot the loss of the circuit too. So this 400ma to the LS should be around 700ma from the cells which is also what Craig measured it at.

But you weren´t answering and possibly also not getting my point anyway - lemme repeat - lets suppose three cells are resistored down to the same average current lambdas circuit is driving the circuit at - so it will IMO drive the LS at the same brightness too - so I was obviously challenging your point that driving a LS with 3 cells will only be 75% as bright as Lambd´s 2AA mods - the possible explanation that it might be brighter because its impulse driven typically isn´t the case with LEDs - and I talked about the average current to have a fair comparison.

There is no reason at least known to me why a LS driven at the same current/voltage from 3 cells with a resistor or direct driven (whatever it needs to get the same current than lambdas 2AA circuits average current) to NOT have the same brightness than a 2AA setup with boost / regulator circuit. If there are any points I might have missed I´m open to learn
grin.gif


Klaus
 

Daniel Ramsey

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All I know is that I have done the 3AA Legend Luxeon mods, quite a few of them, heck a member even has one here it was a pea green LS though, still lambdas is brighter however precise you want to make it. If I want precision I will buy a SF, or make my own.
BTW, the 3AA is just one AA in length longer, too cumbersome IMHO.
 
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