If your 2 children are under age 17 at year end 2018, they would each qualify for $2000 of child tax credit which is subtracted from your tax liability before the electric vehicle credit can be subtracted. If you had no other credits, you would need $11,500 of tax liability to qualify for the full $7500 of electric vehicle credit. A couple filing married filing jointly would need $113,186 of adjusted gross income to have $11,500 of tax liability and qualify for the full $7500 of electric vehicle credit.
