Question about LED drive current?

[ErickThakrar]

I just got a Cygolite Hi-Flux 100. Now, I'm planning on upgrading the LED to a Seoul P4, and I'm curious about how much current the LED is pulling. I don't have a multimeter, so I can't actually measure it, but if I know the run-time and the approximate rating of the batteries, could I figure it out that way?
The light uses 4 C-Cell Alkaline batteries and is rated for 25 hours on high and 200 hours on low. It's a Luxeon III LED. Any ideas?

 

[Szemhazai]

Rating says nothing.... You have to know battery capacity and real burn time on high (before it starts dimming) and then you can try to count current.

 

[half-watt]

Rating says nothing.... You have to know battery capacity and real burn time on high (before it starts dimming) and then you can try to count current.

S,
by rating he probably means battery capacity (though he uses the term rating a second time and means something different that time).


ET,
a "guesstimate" would be 333ma draw on high. but, that's just a "guesstimate". it's not even an estimate. it could be quite a bit higher as when the supply voltage drops, depending upon the circuitry in your light (again, i know nothing about your specific light), at some point, it won't be able to supply the required current and the light will start to dim as the prev. Poster mentioned.

without knowing more, i GUESS about 333ma or so. it's NOT going to be accurate. the figure just takes an approximate 8350mAh capacity for the C-cells (at the nominal +6VDC) and divides it by 25 hours, giving an answer in "ma".

so, until someone who knows more about your specific light's specifications comes along, this is the best GUESS that i can make.

sorry, i can't be more help.

 

[ErickThakrar]

It's a start! Thanks! I'm thinking it's gotta be higher than 333, it's pretty darn bright on high, especially for a Lux III. Meh, I fired off an email to the manufacturer, hopefully they'll be able to tell me.

 

[Walt Dizzy]

Eric,

Pardon me if this was not your intent, but isn't the important amp number the driver output? That is what determines which LEDs can be used in the light without replacing the driver. The amps that the driver is consuming will determine the run time if that's what you're after.

According to the spec sheet:

http://www.lumileds.com/pdfs/DS46.PDF

They can be driven up to 1400 mA. You won't know what the driver output is without measuring it or getting the information from the manufacturer.

Walt

 

[narajjang]

Hi-Flux 100 doesn't have a current regulating driver.
A resister is used.
And you can simply change original LED to Seoul P4 LED.
Vf and current of both LED is similar.
So run-time will be same after change.
But brightness will be much improved.

I have been changed same way.

 

[ErickThakrar]

Thanks, Naraj! I just upgraded mine the same way, last night. Question for you. Do you know what the resistor is that's used in this light?

 

[msxtr]

Thanks, Naraj! I just upgraded mine the same way, last night. Question for you. Do you know what the resistor is that's used in this light?

Hi, you can use a "voltimeter (fluke or similar) to see what valour of resistor have the light.

What heatsink will use you with the hi-flux??

Greetings - Saludos

 

[ErickThakrar]

I don't have a multimeter to measure it with, and I'll be using the heatsink that the light already comes with. I've already swapped out the LED and it's working fine. I'm just curious about eeking out some more light from the LED.

 

[narajjang]

double post....sorry...

 

[narajjang]

I remember...the resistor is 4.7ohm...

 

[ErickThakrar]

Huh. I looked at mine, looks to be a 5.1 ohm. Now I'm thinking about putting something like a Downboy on it.