No.
The law specifically says:
The term “qualified solar electric property expenditure” means an expenditure for property which uses solar energy to generate electricity for use in a dwelling unit located in the United States and used as a residence by the taxpayer.
The reverse situation is covered in Question 25 here.
https://www.irs.gov/pub/irs-drop/n-13-70.pdf
Q-25: If a taxpayer installs solar electric property other than directly on the taxpayer’s home, may the taxpayer claim the § 25D credit?
A-25: Section 25D(d)(2) defines a qualified solar electric property expenditure, in part, as an expenditure for property that uses solar energy to generate electricity for use in a dwelling unit that is used as a residence by the taxpayer. Therefore, if solar panels that are not directly located on the taxpayer’s home use solar energy to generate electricity directly for the taxpayer’s home the taxpayer may claim the § 25D credit. [emphasis added].
In your case, because the solar panels on the garage do not generate electricity that can be used in a dwelling unit, the garage system does not qualify. It would qualify if the garage system was connected to the home system so that the garage system supplied power to the dwelling.
