question

@KarelHolubicka Hi, I am seeing unusually big difference between voltage reading on Multi vs SmartShunt+MPPT.

I used to see similar discrepancies with my system with my multi due to less than optimal voltage drops when under high loads/charging.

My solution was to hunt down the connections that were causing excessive voltage drop, and then to apply DVCC to my system so all devices were acting on the most accurate voltage reading (BMV).

I see the discrepancy under (almost) no load - see the graphs. And DVCC is not an option to me due to used battery BMS. Thanks anyway.

What is your wiring like? (Diameters and lenghts on each device?) Voltage drop may be a result of unsuitable cable sizing.

Also Fuses range around 100mV voltage drop as well.

As per documentation the MP is able to compensate a voltage drop of up to 1V, you may wanna setup voltage sensing as of the documentation to simply let the multiplus compensate?

4.4.5. Voltage sense

For compensating possible cable losses during charging, two sense wires can be connected with which the voltage directly on the

battery or on the positive and negative distribution points can be measured. Use wire with a cross-section of 0.75mm² (AWG 18).

During battery charging, the MultiPlus-II will compensate the voltage drop over the DC cables up to a maximum of 1 Volt (i.e. 1V

over the positive connection and 1V over the negative connection). If the voltage drop threatens to become larger than 1V, the

charging current is limited in such a way that the voltage drop remains limited to 1V.

See Appendix A, Connection overview [32] for the location of the connector.

Hi guys, thank you for your input. However, I need someone from Victron to comment this, please, if this is common error. I will call the distributor next week anyway. I understand that bad wiring is the usual cause, but I am asking here just because this is NOT the case - difference happens even with 0A current (see logs), not mentioning my cables are 0,5m of 2x2x50mm2, which is pretty adequate even in full load.