Do you have an Immersun type device for automatically using your excess solar power?
That is the best thing we use.
Discussion
No, not yet. I have a few layers of things to do before I get to that:
1. Set up a homeassistant instance.
2. Figure out logging BMS data to the instance to track battery state of charge.
3. Set up a relay that will be controlled by home assistant to turn on when the battery is fully charged
4. Install a DC tank heater that's compatible with "48V" systems.
5. Enjoy much less cost for hot water.