Modding questions.

I have this light I'm thinking of modding. It's a 3 D cell light with 2 3 watt led's. How many volts could 2 3 watt leds take without damage. I would assume at least 9 volts as a 1 watt can take 3 AA's without incident. Also, do they make battery carriers that can put say AA's in instead of D's to increase voltage?

Different LED's can function under different voltages. The top 5W Luxeons can take around 9V, but most are less. From the types of lights that function without electronic drivers I gather that most Luxeons function around 4.5V to 6V.

Lots of different battery adapters have been made. 3AA to 1D, 6AA to 2D, 8AA to 2D, and 9AA to 3D have all been written about here. They are usually limited production items so you have to hunt around to find them. Trying to achieve high voltage this way is usually used with incandescent bulbs, not LED's.

If you want the most simple method of wiring this up, I'd just go with a couple of Lux IIIs with a Vf of either K or L (L would probably be safer) and wire them up in parallel in direct drive fashion. Then I'd just feed them with 3Ds like the light was designed for.

Most of the luxeon IIIs that you will see around here have a forward voltage of about 3v to 3.75v (H - K Vf bins). Driving two of them with 9v, without some sort of buck converter, will likely fry something (even if you ran them in series).