Has anyone direct driven Luxeon 3W with a li-ion battery?

Flashlight Modding and DIY Parts
1

I have a cheap bike light that I bought just so I could use its mount on my bike and mount my flashlight somehow.

However, I got to thinking... I have a couple of old never-been-kissed (used) Luxeon IIIs (3W) stars. I have tried hooking up one to a cellphone li-ion battery, but only for a sec. It didn't burn out, but was very very bright. I also have a couple of heatsinks and thermal wings (lightweight heatstrips).

Now, the bike light formfactor will accomodate pretty much anything, so I was thinking of one of the following scenarios/configurations:

1. 2x LuxIII in parallel, direct driven by 2x cellphone li-ion batteries in parallel. These batteries are 900 mAh each, and are pretty fresh. Vin = 4.2v ~ 3.7v. Capacity = 1800 mAh.

2. 2x LuxIII in parallel, direct driven by 3x NiMh AA's in series. Vin = 3.6v ~ ??

3. 2x LuxIII in series, direct driven by 4x NiMh AA's in series. Vin = 4.8v ~ ?? Capacity = 2000 mAh. This option should have the most runtime but not as bright.

What do you guys think? Should I go for maximum brightness or the safest option? Will option 3 even work?

2

Option 2 should work, and as long as you have decent heatsinking, you should be fine. I have a couple of those left over from old modded lights, and decided to see what they would do one night. Started with a half charged 18650 direct drive with 20 gauge wire, with the star just sittin on my vice. Ran it for a minute or 2 and decided to see what it would take to blow it. Ended up with a hot off the charger 26650 IMR and it did not blow after 3 or 4 minutes with no real heatsinking. Darn tough little led.