Ran the wire from chassis battery positive to my BMV-712 for starter battery monitoring on B2. B1 port has house batteries and it works fine and can get output to app. B2 port not providing readings from chassis batt. Swap the wires and i get reading from chassis batt on B1 but not house batts on B2. B1 port appears to be only port active. I had it set up to read house and mid-point and worked fine. No go on B2 with chassis batt. Have 2 12v/100Ah lithium for house. Suggestions or ideas?