I NEED HELP!!! 14.8 V LiPo, but what LED's

ok I was planning on running 4 X cree XR-E R2 at 1000ma from a bflex buck driver but i have been told that this wont be possible as the foward voltage is to close to the input voltage,

So i neeeeed help,
If you were to make a dive light (narrow beam less then 10 deg) from a 14.8V Lipo battery what LED configuration would you use?

Maximum external diamater of the optics 50mm preferable less (somethis like 40mm would be nice

Run time would have to be atleast 2 hours but preferable more

I open to suggestions, please help me

thanks in advance,
Bradley

id go with 3 MC-Es or P7s in series to get to about 10.8v...

that leaves a large gap between input and output but not so large that it would be damaging

but that may be expensive so your call

3 X cree XR-E R2 with a bflex will be perfect.

Forget the multi-emitters (P7, MCE, etc) if you want a tight/intense dive beam. They will work great for video and flood type applications, but not much else than that.

Check out packhorse's mods. This one uses Q5's, but I've just built a dive light with most of the same specs but used R2's instead. It's a GREAT light.

http://sods.freeforums.org/here-we-go-again-t610.html