The conflicting current paths is what I was wondering about. I was thinking with an alternator providing current, loads can be handled without the current path ever going through the battery and shunt.
If just using it as a battery monitor that is all you really want, the current going to and from the the start battery. For the most part that should look pretty uneventful. You would see a large amount of current used to crank the engine, and then a relatively large amount returned back once up and running. At some point that should tapper off to little or none going to the the battery, instead just being consumed by the other loads. It doesn't really take that long to replenish the starter.
Of course if your house charging loads are higher then what is available at say low idle, that would be interesting to see. As it should then consume power from the starter.
You could use the shunt configured to monitor the alternator output (source) and track that. I personally find that more interesting and useful. If you are also monitoring the amount going to your DC-to-DC or to your house battery , you could get an idea how much is going where.
The larger shunt would allow you to read the full current load, but of course is less accurate for lower current readings. It would be interesting data though.
My Transit has a SOC meter, I monitored it for about a month using Forscan (80% is considered full charge). I only have a couple of small loads that get used when the engine is running, so nothing really interesting for me to see. That and generally you only have access to that when the vehicle is running.
I don't use the Victron Connect phone apps very much, but I would think they give you a history of what the starter voltage is reading. ( I can get it using my Cerbo GX) I might check next time I'm out by the van.
