@bobro Do you have the wifi dongle setup to be able to use the website monitoring? There are a lot of setting and it can be easy to missing going through the onboard menu. But I do have a few suggestions.
Based on the batteries you are using 4 x(12.8 volt 100amp hour) batteries wired in series you have a 51.2v 100amp hour pack that has a total of 5,120 watts of power. Using the 80% rule you have about 4,000 watts of useable capacity. Your batteries are lithium iron phosphate and they have a much flatter voltage curve meaning that 70% of the available power is between 51-54 volts.
I would recommend raising your EOD(on grid end of discharge) voltage to 48-50v. This is setting #11. Once you get to less than 25% capacity remaining on your pack the voltage will drop fast even under light loads. Once the disconnect voltage is reached and the load is removed the voltage will recover a good bit and if the inverter is charging the pack the voltage will raise fast and is easy to get to the +3v from disconnected voltage and that can cause the cycling effect.
Also if you are wanting to disable your AC charging Setting #14 AcCh: should show diS for disabled.. If you can't get this setting you can try the website. Go to the maintenance tab and read the setting from your inverter. It is easier to see all the setting. I hope this helps
