Delta Pro Batteries Plus Smart Home Panel and extra Smart Batteries Purchased in 2023

Hello, we purchased a Ecoflow Battery System for our home in California.  It is tied to our Solar System which was purchased about ten years ago.  I enter the total cost on the "Enter Any Residential Clean Energy Improvements" page under "Qualified battery storage of at least 3 kilowatt hours," and the refund counter immediately credited us with the 30% that we were expecting.  Then, after the page confirming our address, it again asks for Fuel cell property costs and Kilowatt capacity of fuel cell property.  Our battery has a Kilowatt capacity of 23.5KWh, and so I entered that, but I am confused about what the "Fuel cell property costs" is referring to.  Is the fuel cell property the solar panels that the batteries are connect to or the batteries themselves?  Any help is appreciated.