Victron energy BMV-700 Manuel page 10

Battery bank bottom section voltage
Compare with the top section voltage to check battery balancing.
Battery bank mid-point deviation
Deviation in percent of the measured mid-point voltage.
Battery bank mid-point deviation voltage
Deviation in Volts of the mid-point voltage.
2.2 Synchronizing the BMV
For a reliable readout, the state of charge as displayed by the battery
monitor has to be synchronized regularly with the true state of charge of
the battery. This is accomplished by fully charging the battery.
In case of a 12 V battery, the BMV resets to "fully charged" when the
following "charged parameters" are met: the voltage exceeds 13.2 V and
simultaneously the (tail-) charge current is less than 4.0 % of the total
battery capacity (e.g. 8 A for a 200 Ah battery) during 4 minutes.
The BMV can also be synchronized (i.e. set to "battery fully charged")
manually if required. This can be achieved in normal operating mode by
holding the + and – buttons simultaneously for 3 seconds, or in setup
mode by using the SYNC option (see section 4.2.1, setting number 10).
If the BMV does not synchronize automatically, the charged voltage, tail
current, and/or charged time may need adjustment.
When the voltage supply to the BMV has been interrupted, the battery
monitor must be resynchronized before it can operate correctly.
8
BMV-702 only, when the auxiliary input is set
to MID.
BMV-702 only, when the auxiliary input is set
to MID.
BMV-702 only, when the auxiliary input is set
to MID.