Cree Q5 direct drive?

[ktafil]

Hi,

I want to built in a Cree Q5 in a AA m@g.
what is the best way to go on?

2xAA cell
1x14500 cell?

dan i direct drive it on the 14500? or 2xAA?
Or do i need a resistor/driver?

 

[linterno]

I have a Romisen RC-W4 which is completely direct driving a CREE P4 and nothing happened to it after months of use with a 17500 Li-Ion battery. The led is pulling 1400mA from the battery when fully charged and gradually dims as the battery gets discharged,

 

[ktafil]

So how sure are you that is will work for a Cree Q5 as well?

 

[yo6ial]

I modded this with a Q5 and is powered by a much bigger 18650.
In about one hour, the entire torch gets a mild fever, but it doesn't peak above one amp with fresh charged cell.
Now my father enjoys it, as i bought another and dropped a ssc p4 in for the wider spill and wider spot.
Just check the current with a (as in "one" and not "two") slightly discharged 14500 cell and make shure it does not pop over 1amp or so.
With proper cooling, those Cree leds will take a beat and then some.

p.s. It will not get lit at all with two AA cells. Perhaps it will put out a few candles at most.

 

[ktafil]

Just check the current with a (as in "one" and not "two") slightly discharged 14500 cell and make shure it does not pop over 1amp or so.
With proper cooling, those Cree leds will take a beat and then some.

Thanks for the advice.... i'll try with a 1/2 discharged 14500 first.
I hope it will not

 

[linterno]

So how sure are you that is will work for a Cree Q5 as well?

StefanFs has driven CREE Q5s at 1500 and 1600 mA. With proper heat sink there should not be a problem. As some people write here, your LED will not last 100000 hour but will last enough (2000+ hours).

 

[ktafil]

Sounds promising.
Now just waiting for the stuff to get here :naughty:

 

[ktafil]

Okay, here it is.....

I built the MM with cree Q5 running on a single 3.7V 900mAh Li-Ion

When running it pulls 1.9Amps on 3.5V from a just fully charged battery
This is quite a lot, i'll re-measure the Amp's later when the battery is used for a few minutes (have no multimeter here now)
I hope the LED will not in the meanwhile, but it surely is a lot of light for a MM! :naughty:

 

[Greg G]

I run Cree XR-E's in DD occasionally, and I carefully sort through the emitters I have on hand to find one with the right front voltage that will work with *that light*. The resistance of the switch affects it a lot. I have seen XR-E's pull from well below 1 amp to over 2 amps off an 18650.

If I were you I'd add in a resistor to get the current down.

 

[ktafil]

Okay, here it is.....

I built the MM with cree Q5 running on a single 3.7V 900mAh Li-Ion

When running it pulls 1.9Amps on 3.5V from a just fully charged battery
This is quite a lot, i'll re-measure the Amp's later when the battery is used for a few minutes (have no multimeter here now)
I hope the LED will not in the meanwhile, but it surely is a lot of light for a MM! :naughty:

Okay, after the freshness is off the battery i measure:

3.4V / 1.3A --> this is what I have read before.
It will shorten the LED life, but sill still be a lot.
The Apm's are ,measured at the tailcap, so switch resistance will lower the Amp's a bit with the wsitch in place.

The light is sure very bright for a mm

http://www.candlepowerforums.com/vb/showthread.php?p=2864183#post2864183