I love my C-Max most days. I get 50+ mpg under perfect conditions (warm weather, 55mph or less) and 42mpg overall. It has also been nice to get checks from Ford each time they downgrade their mileage estimate. But twice now the battery has been dead in the morning for no apparent reason. The heated seats and radio and lights were all off. Both times the car was at home, and I happen to have a spare 12 volt battery that I could bring up from the basement, so it was no big deal to jump start it.

But I would like to have some words with the engineer who decided to omit putting a key lock on the back hatch. Getting into a CMax with a dead battery involves unlocking the driver door (the only door with a key), lowering the seat-back so I can climb into the back seat, lowering the rear seat-back, transferring everything from the cargo area into the back seat, and then reaching back to raise the cargo area floor to get to the jumper cables. It would be a lot easier if I could just unlock the back hatch from outside the car. I don't really want to keep my jumper cables in the passenger compartment, but that is where they will be from now on.

Intermittent dead batteries seem to be a pretty common problem, based on complaints I have seen on the Internet. Has anyone found an explanation or solution?

Update from Dec 16, 2014: The dealer replaced the battery and updated the software today. They say that this clears up the problem for people who have this issue. It was all covered under the warranty.

We purchased Ford 2013 CMAX SEL new (leftover) on July 2014. One morning, when car had 360 miles on it, it would not start due to dead 12 Volt battery. After jump-starting it, it started and ran for about one week. Then, week latter, with 820 miles on it, the transmission got stuck: would not show what gear it is in and could not be moved to P,R,N,D,L gears. Front wheels would not turn, towed it to dealer.

Dealer told me that this issue is due to low voltage on 12 V battery. They tested and recharged battery, updated screen software, which drained battery when car is off, and returned it to me. Three weeks latter 08/29/14, same issue: transmission locked and car becomes unusable. Called Ford Road Side Assistance, told a tow truck driver about low battery voltage. He charged my battery to the point when gear selector can be moved. I decline trip to the dealer since it is a Saturday night of a Labor Day Weekend and I need to be at work first thing Tuesday morning.

My solution, went to WalMart, bought battery charger, and recharged 12 v battery. In the future will periodically charge 12 V battery until will have a time (in near future) to drop my car off to the dealer for the repair. Hopefully they will give me a loaner, and finally fix this car.

MAY 2014 TO DATE I HAVE HAD CMAX DEAD IN THE GARAGE ABOUT ONCE A MONTH. BOUGHT THE CAR DEC 2013. I AM A SENIOR 88 YRS OF AGE BEEN DRIVING SINCE I WAS 16 YRS OF AGE. NEED A "DEPENDABLE CAR" FOR DOCS, DENTISTS, GROCERIES, ECT ECT. USUAL PROCEDURE HERE IS TO UNLOCK GARAGE DOOR, OPEN C/MAX DOOR & IF LIGHTS GO ON, I AM GOOD TO GO!! IF NOT, CALL ANY OF THE 10 TOW TRUCK FELLOWS IN MY TOWN, THEY ARRIVE WITHIN A HOUR THEN I GO ON MY WAY HOPING THE DAM THING WILL BRING ME HOME AGAIN WITHOUT HAVING TO HITCH A RIDE ALONG THE HIGHWAYS HERE IN CALIFORNIA!! OH YES, FORGOT TO MENTION MY LITTLE ESCAPADE AT THE FORD DEALER...PICKED UP MY C/MAX AFTER LEAVING IT A FULL DAY & OVERNITE FOR "ACE MECHANIC" TO FIND "THE GLITCH" DROVE HOME, CHECKED OUT THE INTERIOR & FOUND MY INSURANCE PAPERS, CA REG PAPERS, DAUGHTERS EXTRA KEY & MY EXTRA KEYS ALL MISSING!!! I BOUGHT THREE FORDS AT THIS DEALER LAST YEAR. HAD FORD TRUCKS & CARS FOR YEARS, CEO NEVER BOTHERED TO WALK OUT OF HIS OFFICE TO APOLOGIZE TO ME FOR THE THEFT, C/MAX PROBLEMS, INCONVENIENCE CANCELLING APPTS. ECT. ECT. THANKS HENRY!!!

Car battery has gone dead now twice, once in my driveway and the last time I was on vacation in Wyoming 2000 mile away from home. Each time Ford sent a tow truck to jump start and car worked fine. Turned car into Ford Dealer this morning, 6/26/2004, for them to check it over and see if they can come up with something other than jump starting the car. Ford has come out with a few suggestions for the tech's to check and the service manager said the engineer's at Ford are working on the problem trying to come up with a definite cause and fix for the problem.

I have read other reports about the mileage everyone is getting, last year I went to Wyoming and returned about 5500 miles and averaged 48 MPG. This year after the upgrade that allows you to drive on the battery up to 85 MPH my trip out to Wyoming I averaged 46 MPG. My first trip I kept the speed to 60 MPH, this trip I did the speed limit mostly 70 and 75 MPH with the mileage approximately 46 MPG. Driving around town here its always been from 44 to 48 except in the winter when it decreases because the engine runs more frequently.

For the third time now, (over 3-4 months), we park the car, (for 6-8 hours), and the battery goes dead. After a jump start it runs fine for a time.

The first time, the dealership could not duplicate the problem therefore could not fix the problem. The second time, they said the battery tested bad and replaced it. I had my doubts at that time.

My opinion was that something had to cause the battery to go bad such as a faulty relay or faulty circuitry design. And especially due to the fact that I have heard of several other cases of this exact problem with other C-max owners. In fact, we bought two new C-maxs about a week apart, (one for our daughter and one for my wife). And within the first couple of weeks, our daughter's car battery went dead sitting in the driveway. After a jump start from roadside assistance, it was fine until today, several months later. We have also heard from neighbors, and service managers at the dealership, of several other cases like ours.

We have also contacted Ford regarding this issue, hoping to get a satisfactory repair or replace the car. But, that's a work in progress.

Update from Jan 6, 2014: After taking our car into the dealer, in response the 13B12 letter we received from Ford in December 2013, for more adjustments to fix this problem, the problem reoccured this morning. My wife parked the car Sun Jan 5 2014 at 5pm, came out to go to work at 5:30 am Mon, and the electrical system was dead again. As usual, I called for a jump start and took the car to the dealer. I would greatly appreciate someone contacting me regarding this problem. It is obvious Ford has no idea how to fix this "lemon", therefor, we would like a new car to replace it. We have been patient and cooperative with both the dealer and Ford on each occasion this problem has inconvenienced us. We can on longer tolerate this undependable car.