I thought those clamp ons were AC only
Oh I don't know, I just assumed you must be able to get dash gauge via clamp application in AC or DC, because, for example, I have a Klein Tools CL380 diagnostic clamp tool and it can read AC or DC amps using the inductive clamp probe on it.
I honestly didn't check on it specifically for this case (on a dash gauge application). I guess maybe we could look and see if they make standalone clamp-style dash gauges for DC.
You could use a shunt no problem I suppose, just have to cut the wire is all (I'm not a huge fan of cutting the factory vehicle wires if I can avoid it, unless I can do it cleanly and make it professional, factory-like, keep it weather-tight, etc).
In the old days they used to just sell simple amp-meters for cars, that you could install in a circuit, and you'd cut the wire and put it in between, and the needle would sit in the middle if there was no current flow, and read positive or negative amps value depending on which way the current was flowing. They probably just had a small shunt mounted inside them.
It seems like someone would make a DC clamp solution though, I'd have to Google it some more.
