If you have enough income to have an $11,500 tax liability, the combined credits for the 2 children and the EV would offset the $11,500 of tax liability and you would get a refund of all of your $6,800 of withholding. Even if you don't have enough income to have a $11,500 tax liability, the combined credits would be enough to offset all of your tax liability and you would still get a refund of all of your $6,800 of withholding. You don't get a refund from any unused credit amounts.
