I have my AC300 connected to 2 B300 + 2 Vatrer Rack batteries. It all works well, but the B300 SOC goes crazy when it fluctuates in cloudy conditions for a few days. If I get the batteries to fully charge, it all works great. If not, 1 B300 might say 3%, the other 30%, and the Vatrer's might say 60%. I wager the voltages are all OK, but it's a bummer if I truly have 60% battery left, because the AC300 will switch to grid power prematurely - just $, not safety, fortunately.
I've also had one B300 think it's charged, and the other at like 50%, and will jump up 30% in a few minutes. I think it's a Lifepo4 thing, with the voltage curve being so flat.
Either way, I hope we get more sun before EOD, as I'm stuck at 27% and won't make it through the night yet!