I realize this is an old thread, and it somewhat drifted from the title. But, I happened to be playing with my carputer today and captured these pictures that pretty much tell the story. It is late September but a sunny day in the PNW, and the SOC or the battery is about 78%. I have about 15.03 Amps coming from my solar controller. Of that 4.58 is getting to the battery. Currently Carputer, stereo and refrigerator are running.
The next shot is after I start the Van, as you can see the alternator (via the Blue Sea ACR) is providing 11 Amps of power, the solar controller has dropped to 14.3 amps for a total of 25.3 Amps, we now have 16.09 amps going to the battery.
And lastly I disconnect the panels from the solar charger and we see the result. We now have 24.6 Amps coming from the Alternator with 16.04 amps to the battery
The Solar and Battery currents are read using Shunt Resisters, while the Alternator is measured using a Hall Effect Sensor. (read that as slightly less accurate)
-greg