*Disclaimer: A tax credit is allowed for the purchase price of a qualified plug-in electric drive motor vehicle acquired. The credit amount is $2,500 plus $417 in the case of a vehicle which draws propulsion energy from a battery with not less than five kilowatt hours of capacity, and an additional $417 for each kilowatt hour of battery capacity in excess of five kilowatt hours. Thus, the maximum credit amount per vehicle is $7,500 (Code Sec. 30D(b)). For qualified vehicles used in a trade or business, the credit is claimed as a portion of the general business credit. For qualified vehicles used for personal use, the credit is treated as a non-refundable personal credit. The credit is claimed using Form 8936.
https://www.irs.gov/instructions/i8936/index.html(Qualified Plug-In Instructions)
https://www.irs.gov/pub/irs-pdf/f8936.pdf (Qualified Plug-In Form)
http://driveclean.ca.gov/pev/Costs/Vehicles.php (More info on vehicle credits and rebates for California)