Supply 5V to Arduino I am building a quadrocopter with an Arduino Uno as control unit. I know I can supply 5 volts to the 5V pin, but my ESCs produce 5.5 volts, which I measured with my multimeter. Will this voltage drop to 5 volts when I connect the Arduino and if not are 5.5 volts to the 5V pin a problem?

Edit:

My Arduino was running well for a couple of days on this setup with 5.5 volts to the 5V pin but died yesterday. By dying I mean the ATmega doesn't execute any code anymore, the L LED doesn't blink, and even a loopback test fails, which is a sign of a defective USB connector. But I am faced with the same challenge. Should I run my Arduino on 14.4 Volts from my 3S LIPO to Vin or supply 5.5 volts to the Vin pin?

Actually I just realised when I measure the voltage from the ESCs they deliver 9 point something volts for half a second when connecting the multimeter, I guess this voltage spike killed the Arduino.
I'm going to assume you are using the UNO model - or any other board based around the Atmega328p.

According to the datasheet the voltage limits are 1.8v to 5.5, with an absolute maximum of 6v.
You should be fine - but if you are able to get the voltage down closer to 5 volts, I would recommend doing that instead.