I have a Victron MPPT 150v 45A Tr unit, works great and bluetooth works well also. Why or what advantage would I have getting a Victron BMV-712 battery monitor? I understand having temperature sensor option is nice, but the app seems to provide very same information for both my MPPT controller unit and battery monitor.
The BMV monitors the state of your battery bank, which the MPPT does not do... the MPPT is showing you what the battery voltage is (although it's not nearly as precise in those measurements as the BMV), but the BMV measures the SOC of your battery bank, the Ah in and out, the time remaining in your battery bank, and also offers contacts for external relays and many other options.
The readings from your MPPT show you a rough measurement of one portion of your system only; the BMV offers comprehensive monitoring of your entire system. It's effectively the difference between having a mechanical oil gauge in your vehicle that is actively measuring the actual oil pressure of your engine or only having an idiot light in your dash that says "check oil"... sure, both of them technically tell you if something's wrong with your oil, but one of them (the BMV) tells you what's going on before your system experiences failure.
