Multiplus II 48/5000/70 + Epever Charger + Sunlight PowerESS 48V battery

Q&A and troubleshooting
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1

my client had:
Charger: Epsolar Tracer 10420AN MPPT 100A

i sold him:
Inverter: Victron Multiplus-II 48/5000/70-50
Battery: powerESS Sunlight 48V/5.12kWh Stack
i want to program the inverter via VE.config in order to achieve the following rules and in AC2 i connected an air conditioner:
AC2→relay on →SOC >75%
AC2→relay off →SOC <70%

the general idea is that if the air conditioner runs i want to protect the system from drying up the battery_charge.

the problem that i have now is the fact that battery monitor inside of inverter refreshes the battery charge (SOC Value) if and only if i connect the inverter to the grid or via generator. the calculation of the SOC is updating if and only if there is a charge function [AC-IN Active]. as i understand it i need to add a Cerbo_GX to the system in order to communicate the Battery_Bms←→ Cerbo_GX←→Multiplus.
is there a way to achieve that without the Cerbo_GX?

thank you

2

Your battery type?

i see two problems:

Normally you use the batteries BMS to monitor the SOC value via CAN cable which is connected to Cerbo GX and Multiplus.

The other problem i see is that the solar charger is not steerable from batteries BMS

3

A. the multiplus can measure voltage. i dont know if the SOC calculator inside multiplus can update the battery capacity everyday from the battery voltage or the battery capacity is updated every time AC-IN is available (charge from grid or generator).
B. the solar charger doesn’t matter so much if it can do its job, meaning that Absorpion Voltage = 56V & Float Voltage=54,6V.
the holy grail here is to find a way to make the inverter read the SOC from the battery bms (or calc some value close enough) and when SOC<70% the AC2 power cuts off.