If you can get you charger wired before your battery system if not put a Shelly CT on it to see when it’s charging. My charger is before everything so doesn’t drain the batteries. It works totally independently this is the layout
It’sa lot of hassle due to the location and distance from different things. Preferred solution is to sense the hypervolt is charging when outside scheduled hours and disable ess. I’m thinking combination of home assistant with Victron mqtt plugin
Easily done with a Shelly EM and HA as I have HA announce when the EV is charging in peak times due to Octopus 
doing an unprompted charge so I don’t freak out when my smart meter starts moving to usage lol