As for mixed batteries. I do have software (in development/debug/trial stage) that acts as a "Software BMS". The software collects data from each EG4 LifePower4 battery as well as each SunGoldPower battery (and a Victron Shunt). The software listens for and responds to the SGP Inverter BMS queries (there are three). The responses to the inverter represent one big battery which reflects the SOC (average) and voltage (average) of each battery in the stack. The software has the ability to fudge the data going back to the inverter to better manage battery charging.
So far trials are looking good.
One issue I am having is getting documentation for the communications between the EG4 Communications Hub (or Master EG4 LifePower4 Battery) and the EG4 LifePower4 Batteries as well as the response from the batteries. I can eventually parse/break it down but documentation ensures my assumptions are correct.
I had sent an email to Signature Solar (I purchased the Hub from then) requesting the documentation and their response; "Contact the manufacturer", I have tried that also with no response, go figure.
@EG4_Jared,
@SignatureSolarJess