That's a great question. I don't see why not. If you put the batteries in parallel you're only increasing your capacity not the voltage. But even with Ford I believe they have 300 volt Max rated system. So even if you increase the voltage you're still okay up to that amount. I want to do the same thing in my hybrid. All I want to do is increase my battery storage capacity so I can keep it on electric mode for longer during errands around town. It also be awesome if I can increase the voltage so the electric motor is the main drive and the engine is the range extender. I've looked all over online and have found many people doing many different unique things. I do plan on getting an extra pack and figure out a way to make it work in my c-max and seeing what happens.
