$7,500 Federal Tax Credit for Purchase of Electric Vehicle

To take advantage of the $7,500 federal tax credit for the purchase of an electrical vehicle I must owe at least $7,500 in federal taxes.  If during the year I deduct enough taxes from my pay check and don't owe any money to the government at year's end, will I forfeit the tax credit?  Do I need to increase the number of allowances (exemptions) such that I owe at least $7,500 by year's end?