It's interesting how retrofit companies build batteries. I had no idea it cost so much.

As for the FEH plug in, Ford won't disclose the battery supplier but in a recent interview five suppliers were said to be under consideration. It's likely that only two or three are contenders.

Johnson Controls/Saft is generally considered the most likely candidate. They are making a big move into the market and are positioning themselves as "the" North American supplier of hybrid vehicle batteries.

If I had to place a bet, I'd guess that the evaluation vehicles are running JCI batteries.