Hi
I have 4 x 3.6kW Pylontechs coupled to an Axpert 5 mkii with 10 x 350W panels in two strings of 5 each. In every daily cycle I get a code 04 warning (battery low). I seldom get to the full charge at 53.2V. It ussually stops around 52V at the end of the day. As soon as PV charge stops I get code 04 at say around 49 - 51V battery power. It takes the whole night to get to say 48.5V when the PVs kick in again. Is this normal for Lithium Ferrous batteries. It seems that their band of operation is fairly narrow at 48V to 53.2V.
Regards