Will the Arduino board burn down?

Please, check out Tim Nolan's MPPT controller project for the schematic. It is something which I will be incorporating in my project.
http://www.timnolan.com/uploads/Arduino%20Solar/ArduinoSolar.pdf

Some Observations:-

  1. The input of the solar panels is directly connected to the Vin of the Arduino. [ MAX Value = 9V ] Here, I'm assuming the onboard voltage regulator will step down this voltage to 5V.
  2. At Analog pins A0 and A2, the Solar panel voltage and the Battery voltage are computed through a potential divider and I'm assuming that this potential divider drops the voltage to 1.622 volts ( correct me if I'm wrong ).
  3. The Solar panel's current value is computed by the MAX4173H IC, which is a high side current sense amplifier.

My query is that, will this have an effect on the Arduino Board? I mean, is the Arduino board capable of handling these voltage levels. [ Raw input, Analog 1 and Analog 3 ] ?
Further, if I connect this system to the PC via the USB port, that's an extra 5V. I think this 5V is set parallel to the previous raw input voltage. Thereby, the voltage must be constant. However, will the current be an issue?

Arduino has voltage selecter. If Vin/2 is >3.3V, the USB from PC is disconnected.
9V on Vin and 1.622 on Analog inputs are fine.

CrossRoads:
Arduino has voltage selecter. If Vin/2 is >3.3V, the USB from PC is disconnected.
9V on Vin and 1.622 on Analog inputs are fine.

Going by that, Vin/2 will be 4.5V in this case. So, the USB from PC will get disconnected ? I need to perform data logging and thereby will require the arduino to communicate with the PC.

Just the USB power. Data lines are not disconnected.

Okay. So, this means that the data logging part will not be affected. The arduino can continue to serially communicate with the PC through USB and send data for furhter analysis, right ?

Could you please elaborate on what happens when Vin/2 < 3.3 V? I'm assuming that the USB power is used to run the Arduino board when the Vin isn't sufficient. Otherwise, like you mentioned, it gets automatically disconnected ?

Power - and only power - switches over automatically. Note that the regulator is not disconnected, so if you feed less than the critical amount to the regulator, it continues to supply power as best it can, down to less than 5V.