I have a single power supply that will be powering an Arduino Mega 2560 and a solenoid. The solenoid could draw up to 2A (probably more like 1A typically, but I'd rather design for 2A). Can I use the Vin pin to draw power for the solenoid or should I split off a wire before it goes through the Arduino?
I've read that the UNO has a diode that prevents pulling more than 1A through the Vin pin. Is this true of the MEGA 2560 as well?
Yes, same diode, same design, used for polarity protection, has a nominal 1 amp continuous rating.