Most of the time the reading is right. But erratically the BMV displays an auxiliary battery voltage in the 5 volts range. When the problem occurs, the actual voltage at the B2 input is ok (ex.: 12,43V) (Measurement made with a handheld voltmeter). All other values including house battery are ok.
Last time this occurred, it lasted 20 minutes, then came back to wright values,
Connections are perfect. Firmware is up to date.
Any clues?