Thanks @barneyd! I already tried the SunSpec-thing, doesn’t work either. I searched the forum here with the errors I’m getting, even installed a new version of the Modbus binding. Still nothing. mbpoll on the same machine works flawlessly.
I’m not sure SunSpec is the way to go however. It doesn’t have a channel for the battery for example, so it doesn’t give me enough info.
I’ve also found out that the integer-registers are in big endian, which explains why some registers were not giving me the correct data. I don’t know much about modbus so I don’t really know what I’m doing ;-). But at least it means the PDF I linked seems to be correct.