Batteries are only allowable for the solar energy credit in 2022 if they are only charged by the solar system and can't be charged by the grid. Read more here.
https://www.loeb.com/en/insights/publications/2018/03/irs-allows-residential-solar-credit-for-batter...
It's also unclear if this applies to new capacity only or also to replacements. It could be an audit risk to claim the credit.
For 2023, the section was clarified that batteries are allowed whether or not they are connected to a solar system, but only if their capacity is 3kWh or more. There is no distinction made between new installation and replacement.
