Testing of the code that references the 1.1V to the supply voltage and calculating the supply voltage appears promising. The voltage differential between a voltmeter and the Arduino was within .5 volts around 11.5V battery voltage. The actual voltage of the USB power supply did vary from 4.7 - 4.9 volts. These values can be seen in the csv file V_06_Test as seen in the test folder of the batterytester github page. The Current calculations code was adjusted to the following:

BatteryCurrent = analogRead(CurrentSensor);

BatteryCurrent = map(BatteryCurrent, 0, 1023, 0, ActualVoltage);

BatteryCurrent = map(BatteryCurrent, 500, 4500, -500, 500);

This removed one of the remaps. Instead of going to 0-1023, and then to amperage readings, it converted to voltage and then to current readings.

While doing the testing of the voltage, the current reading appeared to be incorrect. It was measuring low. Instead of 38 - 40 it was measuring around 35. I reloaded the Resistor_Bank_Testing program (after being modified with the actual power supply voltage adjustment) into the Arduino to see what current values were comparing to an ammeter reading. Only banks 4 - 7 could be tested due to being below 10 Amps. Currently I do not have access to a 50A ammeter. The amperage difference was 1.3 Amps. An ammeter was measuring 4.4 amps while the DFRobot 50A ammeter was reading 3.1 amps. Thinking this might be an Arduino issue, I checked the output voltage of the DFRobot sensor. This was within .02V of what the Arduino measured. Which was around 3 amps. There is some error showing up with this meter.

The most I can attribute to this error, is that it was 38 degrees F in the workspace. Possibly this was causing the error?