question

ESS is a grid-tied technology which does exactly what you need but it is not used in off-grid setups and generally not with generators (though generators are specifically supported on quattro inverters only).

If you have grid then with ESS you can set schedules and battery minima which will control when the system goes to grid, but inside the set parameters will only run off battery and PV.

It requires a GX device and the ESS assistant loaded.

Reading material:

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/index-en.html

You did not mention what equipment you already have.

GX & ESS give you virtually endless posibilities.

E.G. Grid (shore power) set to 0 and SOC to 50% will draw from bat first then if SOC < 50 draw from grid.

Or set grid to 100W so it will, if no solar, take 100 from grid and top up with bat up to set max inverter power, above will take from grid at the same time a set SOC will be adheared to and if bat is low it will take all from grid - also will charge bat with any excess from grid & solar.

This makes power bills very predictable and grid point and SOC can be easily varied (manual or external software) adapted to long range weather forecast.

Hi @Macca61

From a previous post, you have a Multiplus.

Victron don't recommend ESS in your application. It comes with issues that need sorting. Not the least of which is that it can leave lethal ac voltage on the exposed pins of the genset power plug. A real issue if it's not hardwired.

What you need could be easily achieved by using other Assistants. In particular, to operate the 'Ignore AC' function to bring on Grid under your chosen conditions. Could even start the genset too, if you're set up for that.

Well shore power and gen set I dont think so..