Seems a number of people are confused about how to fill out IRS form 8936. Many are starting out with the wrong value and then discounting it to get less than the full tax credit.
If you got your car from 1-Jan-2019 to 30-Jun-2019. your credit will be 50% of $7500 or $3750.
If you got your car from 1-Jul-2019 to 31-Dec-2019. your credit will be 25% of $7500 or $1875.
If you get a different amount, you've likely started with the wrong value.