Hola. I’ve been mulling around options for the better part of 6 months for a solution. I would like to use a 48S LFP battery pack I purchased with a high-voltage hybrid inverter while AC coupling my current Solar-edge grid-tied inverters. The issue I have is that all of the North America split-phase hybrid inverters capable of 80-400V battery integration do not have frequency-shifting, which is how the grid-tied inverters modulate their power output so the hybrid inverter (and potentially battery) does not become damaged when the grid-tied inverters continue to produce power when the battery SOC is full/100%.
The only solution I can think of is a relay that cuts off the AC lines to the grid-tied inverters.
The batrium BMS product(s) can certainly handle the battery management and communication. My question is whether the expansion board can be programmed to signal the AC relay by SOC%?
That is certainly an unfortunate constraint! Any chance you can share where you found the information on frequency shifting?
Generally the hybrid inverter will listen to our BMS over CAN (we have many integration profiles available) as to a safe rate to charge. When the battery is full, we will ask for 0A, and the charging circuit in the inverter will cut accordingly.
But we certainly have configurable logic for firing relays based on battery conditions! For example here are a few of the options you might consider for the application you mentioned:
The hybrid inverter isn’t the issue with turning off. It’s the AC-coupled grid-tied inverters that need to be shut off when the battery is full. As of this writing, the only high-voltage battery (80-400V) hybrid inverters capable of frequency shifting are the Sol-ark 30K 3-phase inverter (that I can find). The split-phase (North American) 240V systems with high-voltage battery do not have frequency shifting, so grid-tied inverters will not receive the signal to turn off. It looks like the image you posted shows the expansion board can send a relay signal based on SOC%, which is perfect.
