Bought my C-Max SE in June of 2014. Had my first auxiliary battery failure after 8 months (Feb 2015). Fine the night before, all systems off for the night, aux battery non responsive in the morning. Dealer replaced the battery under warranty at that time. Car went in for the 15B04 recall/reprogramming in June of 2015. However, yesterday morning (2/14/16) car found "dead" in the garage again! Ford emergency roadside service towed her into the dealer again on "warranty" last night. So, it appears as though this IS STILL an ongoing issue. I will get a jump pack after I get it back from the dealer/service center as a temporary precaution. However, I will probably pursue the acquisition of another non hybrid vehicle now. It appears from other blogs and forums that this problem is NOT just related to Ford hybrids. Don't know why the electrical designers of these vehicles have not over come this apparent under charging issue... This situation is just too inconvenient to put up with indefinitely. Too bad, I like everything else about the car, except for the excessive electrical interlocks, of course! Maybe hybrid again, or full electric someday when this "tech design" issue is truly worked out.
