I have a Quattro V-sense connected directly to my battery bank and two Victron 1000A shunts connected to a BMV each. (One measuring charge coming from a Schneider charge controller, one to measure current from/to the battery bank)
I also have a REC BMS connected to the battery bank and one of the 1000A shunts.
The REC and the 2 BMVs agree on the system voltage being 45.45-45.47v. Even the Schneider tells me it's 45.5v although it has a longer lead to the system. The cables between the battery bank and the shunt are 120mm2 and less than a meter long.
Even while the system is almost idle (no power in/out), and the V-sense is connected directly to the battery bank, the Quattro measures 0.4v lower than all the other equipment.
Manually measuring the voltage everywhere in the system tells me the voltage has no significant difference between measuring at the battery bank, the shunt or at the Quattro.
I can see the lower voltage at the V-sense at any time whether the batteries are under heavy load or not.
Any idea why this lower voltage is measured?