Hi, I'm a seasoned user and seller of Victron gear.
Today, I discovered a 3.6% current discrepancy between a smart solar MPPT100-20, an IP67 charger, a DC clamp meter, a multimeter and 2x BMV-712.
12V battery charging current limit on the MPPT was set to 15A which was matched by the DC clamp meter but the 2x BMV-712s only displayed 14.45A which is 3.6% below the mark. BTW I ensured the 15A was kept constant by feeding stiff and regulated 24V to the smart solar's input with the output wired to a 12V LFP battery @ 50% SOC.
This had me curious.
I then used the IP67 charger with the current limit set to 6A and wired everything including the 2 shunts and 10A multimeter in series with the half charged LFP battery.
The result was similar: multimeter and DC current clamp were showing very close to 6A but the 2x BMVs gave a reading of about 5.78V which again, is 3.6% below the mark. And no, there's nothing else connected.
Both BMVs show zero when there's no current. Parameters 65 and 66 have the default 500/50 so it looks like the shunt resistance is out by 3.6%?