"-" and gnd are connected together. ADC takes all measurements relative to gnd. Therefore the voltage source and ADC must have same groud potential. "-" and gnd connections help to get them onto the same potential by connecting both system gnds together. I recommend to build the voltage divider to b...

If you apply PWM to enable pin you get the motor run-coast-run-coast-run-coast. If you apply PWM to input pin you get the motor run-brake-run-brake-run-brake Be also aware that L298 is only good for motors with running current less than lets say 1A. Its big energy waster and tends to overheat and sh...

As GND is connected to negative input, you shorted the first battery when you wired the second voltage sensor. You must connect all sensor negative inputs to system GND, which is also Rasp GND. Positive inputs you can connect to separate solar cells as long the input voltage is below 25V. Then you c...

Hi. Raspberry has only digital inputs. So if you want measure current or voltage, you need external ADC converter. Please check input voltage range of your ADC and output voltage range of the sensor. You may need voltage divider. For current measurement you also need current sensing resistor and do ...