zorrotto

with the communications the issues will appear. Trust me as soon you switch to LI comms the inverters will not trigger the AC bypass in some modes. Growatt has really big firmware flaws with this. That is also the reason as they are right now telling everyone who reports issues that their batteries are not compatible. The the own ARK modules are suffering of the same issues they are not mentioning... If you are not depending on the SoC of your batteries stick with USE modes...

Run a test with USE mode. US2 expects a comms cable between battery and Inverter and acts pretty much the same as Li modes, only difference being you can set the voltages manually but the BMS comms with Inverter continue and the outcome will be similar to what you now have with Li mode.
In USE mode, disconnect the comms cable, set everything manually as per your battery specs. Leave it on USE mode for a day or two and monitor the battery capacities and voltages directly from the battery. The BMS will (should) manage the battery charge by itself. 
 

I really don't know, and there has been quite a length discussing in this forum, some are in Favour, others disagree. I run my system on user 2 and I'm very happy with the results, I'm verry conservative with my battery settings, my setting for bulk charge is 55,3 V, OEM recommends 56 V, float to 53,5 OEM recommends 54. sometimes does not reach 100% SOC but it goes to about +_ 95% and once a month I take it to 56 V to balance the cells.