I'm not sure, which is the best forum to post this.
Unfortunately, my german skills are 23 years out of date, and I do not recall much of the language anymore.
I've got a website up with a wide variety of information for modders, including LED testing information, switching power supply design, switcher chip choices, and more.
Anyhow, it is a bare bones website, basically just with info, and very little frills and web page bling.
Feel free to visit, learn, and grab whatever information your heart desires.
www.molalla.net/~leeper/led.htm 
