My daughter is set to buy a 2013 C-Max with 114k miles. The dealer (not a Ford dealer) said the battery warranty is for 10 years and that she can buy an extended warranty from Ford for $400 when the ten years are up. Is this correct? Or, is it $400 a year? I know nothing about hybrids and am concerned she may have to pay a lot of money down the road. She is not in a position to do so. She's already started the paperwork, but doesn't have the car yet. She's pretty set on the car, though. I realize any car of that age may have problems, but if this battery goes, it would be a huge expense.