I did an overnight test now. I set the voltage to 5.6V and run the S110 for more than 10 hours!
I measured the tempertature frequently with a thermometer gun on the hottest point I could find. This is on the front side where the lens is, below the Canon logo. If I zoom in and out very often the temperature goes up to 36°C the current then is 600mA. If not zooming, but LCD screen is on then the cam has a temperature of 30°C current is 350mA. If the LCD is off the camera has a temperature of 28°C and current is 110mA.
This morning the camera had a temperature of 28°C and still a current of 110mA.
The cam is still alive and works like a charm...