God damn. After removing the LED i still had 12Volt.
From 10 Mosfets i picket a broken one
So i did some testing now and the electronic in the LED makes problems.
Here are some measurement:
Monitor PWM: 1, Pin 6 Volts: 0.03
D6 = 0.02 Volt
LED = 0.00 Volt (lights up)
LED turned = 0.21 Volt (lights up)
no LED = 11.3 Volt
Monitor PWM: 36, Pin 6 Volts: 0.72
D6 = 0.71 Volt
LED = 2.85 Volt (lights up)
LED turned = 2.85 Volt (lights up)
no LED = 11.5 Volt
If i connect the LED directly to the 12 Volt power supply i have 12 Volt at the LED.
In the PWM circuit i have the funniest volts.
There are allot PWM circuits out there but PWM is what the Arduino does.
Maybe a LED driver?
I found this: http://www.led-treiber.de/html/leds_grundlagen.html#PWM-Dimmer
and they write it works with all there LED drivers: http://www.led-treiber.de/html/getaktete_treiber.html
How about a power supply for all the LEDs and a "reverse phase control dimmer" in front of them
who is controllable with the Arduino?
There must be a way to dim those LEDs with some kind of circuit :-(