Very interesting question that I have a followup question to that maybe someone can explain. First reading your question I thought the meter you meant was an electrical testing meter like a Fluke or a Klein. With those meters amperage is measured with a CT(current transformer) clamp, and it does not tell you the direction of flow. I install solar and batteries and during the testing phase it would be extremely valuable to have the direction of power flow. Sometimes it obvious, sometimes I'll have an imbalanced load and have phase A backfeeding and phase B drawing power, or maybe the battery will be involved but i cant tell if its charging or discharging. I know that permanently installed CT meters give pos and neg values because it has the reference voltage, turning the CT around or to the wrong phase will give opposite values.

How do I get that same data with direction of flow from a field testing meter like a Fluke? Any other meters someone can recommend? Gratitude to any who can help.