Direct answer: The standard Eagle 1000 FR is a 115 VAC operator and Eagle does not list it as a solar-ready model. Eagle sells a separate Eagle 1000 DC platform for battery/solar applications.
Do not solve this by attaching a random panel
Solar compatibility involves the control board, charging system, battery configuration, and power-management firmware. If solar is a requirement, compare the DC model rather than treating the AC FR model as a panel-sizing problem.