Can I take the solar tax credit if I only made a down payment of 10% in 2018 but installation of my solar panels did not take place until early 2019?

[denisetwo2002]

Instructions for form 5695 state  "costs are treated as being paid when the original installation of the item is completed,"  so you will need to wait to take the credit once the installation is complete.  You can use the full amount for 2019 even though part of it was paid in 2018.