Hello,
I have recently created a arduino controlled toy car that you control with your phone via Bluetooth. I was planing to installing an led that will light up when the batteries are at around 4.5 - 5 volts. My question is if the arduino analog pin can read up to voltage that high? Or if they cant what is their max? Thanks for your help.
I assume you'll want to measure voltage higher than 5v? The light would go on at 4.5-5v to signal a low battery?
It is possible to measure voltages higher than Vcc using a voltage divider. See Experiment #2 on this page:
For a more accurate measurement, don't assume a resistor labeled 1k is exactly 1k. Measure your resistors with a quality ohmmeter to determine their actual values and plug those into your program.
Thanks, I have finely found my answer! I think 5 volts will be good enough for me. 
Sam, it might be a bit late, but be aware that 5 volts is the MAXIMUM voltage for a UNO pin. So if you are sensing voltage in the 6 v range, you will need to divide it down before submitting it to the Arduino for testing, lest it be too high, and burn out the pin.
And are you powering this Arduino from the battery? If so it will always read the battery voltage as 1023,
since its ratiometric. In that circumstance another approach is needed, which depends on whether you are
needing to read any other voltages.
This might help:
https://www.arduino.cc/en/Reference/AnalogRead
The voltage regulator on the arduino uno regulates voltages to 5 V DC, so I would think that would be the max.