Are there inverters that do programmable SBU

[Adam De Lay]

I use a chargeverter to do it when my battery is low.
That's not exactly what is wanted here. But it could sorta accomplish the goal.
It's based on battery voltage. If the battery voltage drops below a set point, the chargeverter steps in. The chargeverter is powered by the grid.
This allows me to keep a certain amount of capacity in reserve.
I'm still using battery and solar. And there's no complete transfer.

I had actually looked into doing this with my 6500s. It isolates the inverters from the grid while still giving you the ability to "utilize" the grid. I always wondered if half my issues with the 6500s were due to the fact that I had the grid connected...