From email, Greg writes:
As a quick summary, I have solar panels that are about 300ft from my house. So I use micro inverters to convert the solar DC to AC so that I can use smaller wires to get the power down to my house. There I have an outback Radian inverter and a Mate 3 controller.
So I would like to hook up a simple volt meter to my Arduino Uno that reads the voltage from the batteries.
From what I understand, the classic voltage divider will solve the problem. Optionally, you might want to add an op-amp buffer, which would provide one more layer of protection for the Arduino.
If you skip the Op-Amp (LM358), then the Vout node between R1 and R2 would connect to your Arduino's Analog In. The LM358's VCC and GND pins would be connected to your Arduino 5V and GND.