17kW generator or did a zero slip in?
typically on this size of system the generator would be ~2kVA, so lets assume a 1700 kVA generator.
At 220V, a 1700W generator could produce 7.7A, but this is probably a peak rating. A 1700kVA generator could produce that current, but not continuously. Typical max current would be 6A.
for a 12V battery, this would relate to 110A of charge current, but the inverter is limited to 70A.
If you don’t modify that, then that takes 840W from the generator, leaving only 520W to drive anything else. so a 1kW load such as a small kettle or espresso machine will overload the generator if power assist is off. However, the generator may overload before the power assist can function.
Try raising the Ac input current limit from 4.5A to 6A, and reduce the battery charging current.
Otherwise, a larger generator will be required.