salman

Thanks for pointing this out. I have missed mention of this point in earlier postings or maybe for some reason it did not register with me. I will check my manual and check my 12 volt battery. I gather the CCA is listed on a label on the battery? Or did you need to look up the model number of the battery to check its specs?

I heard back from the West Coast Ford Customer Care Manager. Here is my report on the conversation, with my own thoughts on the matter added along the way: 1) He said that Ford's technical experts have received reports of an unspecific number of cases of 12 volt electrical systems gone dead and that the proper response to date has been to replace the battery, which, in my view, presupposes (maybe accurately) that problem is manifested in the battery. He did not specify a cause for the batteries going bad, just described the response to the symptoms that he said Ford has been finding effective. In my view, if any of you have had 12 volt electric problems after a battery change out, then it is important that you let Ford's Customer Care line know about it. Your cases could help determine whether there is a problem with the battery out of the manufacturer or a problem elsewhere in the C Max electrical systems. 2) The Customer Care Manager also told me there is a new TSB, recently issued, advising Ford dealers to re-program the modules that send door & hatch open messages to the instrument panel. There seems to be a problem with these modules sometimes coming awake at odd times. The TSB is an advisory, not a recall. The technical experts recommend doing the re-programming if there are any incidents of trouble with the 12 volt system. Modules coming awake could drain some power, but in my view these modules should not drain much power. 3) I told the Customer Care Manager what I had found by reading about 12 volt battery problems in other hybrids. Full description is earlier in this thread. Short recap: 12 volt batteries in hybrids are smaller and not as robust as in regular gas engine cars, more prone to being draining, and seem to be more prone to being damaged when drained. They re-charge more slowly, too. Consequently, a car at a dealership driven for 1-2 mile test drives that sits for a month and has its radio,, etc. fiddled with in accessory mode could have its battery drained and damaged. The Customer Care Manager said that sounded like a plausible conjecture of what might cause the problems we have encountered. I suggested dealers might make sure to charge up the 12 volt batteries when new cars arrive and maybe once a week if they sit on the lot to prevent deep discharging of the batteries. I also told him that Optima makes a supposedly more robust after market battery for the Prius. The Customer Care Manager responded to the second of these suggestions by saying that IF sufficient reports come in of battery problems related to the battery being too small in reserve capacity, then Ford potentially might design a more robust replacement battery that it might offer through a Customer Satisfaction Program. The highlighted words are there for accuracy's sake, not a snide comment nor meant to suggest doubtfulness. I thought his response was proper and thoughtful.

Advsysal - Please add your details to the Dead Battery Roll Call Thread and, most important, please call Ford's Customer Service line to log your problem with them as well as with your individual Ford dealer. The Ford central number is posted earlier in this thread.

Samuel3rd Please see the threads on 12 volt battery problems in the forum section on Maintenance, TSB's & Recalls. Please add your info to the thread on "dead battery roll call" and please call Ford's corporate customer service line to log your issue with Ford as well as with the dealer. I have posted the number several times on the other threads. Ford needs to hear from everyone who has had this kind of problem.

Andrewwx Please call Ford's Customer Service line, too, so Ford's central offices know this is a concern. That will ultimately help dealer service and us. Erwhitham On the Prius discussion boards there are lots of owners who say they have never had a 12 votl battery problem and can leave their care for 2, 3 even 4 weeks without driving and then start easily. That is the way it is supposed to be. But there are other posters who say their 12 Volt problems happen within days or less of their last drive. The causes could be a bad or damage battery, or a problem with the charging system, or a short that drains power, or something else that drains power, or a combo of these things. I think the Ford might be experiencing similar issues: no problems for many, mysterious problems for some of us. The Ford customer service manager is supposed to be calling me tomorrow with the results of his research. I will share notes with him and report back on the conversation. Then I will fill in my local dealer, too.

I have had my C MAX SE back since Friday with a new battery from the dealer, though no problem could be identified in the old battery. So far so good. Meanwhile, I had the idea to Google for issues with the Prius and 12 volt batteries, and also with hybrids in general. And there are recurring issues. You can find this pretty easily on Google, but one especially informative piece is here: http://www.examiner.com/article/auxiliary-battery-woes To summarize the contents of that article and other stuff I read: the 12 volt battery in hybrids is smaller, less powerful, and has less reserve capacity than in regular gas operated cars. In addition, the battery charges at a lower and slower rate of 3.5 amps, maximum. What this means is that 12 volt batteries in hybrids are much more prone to being drained out than in regular gas cars. Thus, if you use accessories when not driving the car you drain power. Batteries lose charge over time with the car off, though the car should still start after sitting for 3 or 4 weeks (should is the operative word). Infrequent and short distance usage does not recharge the 12 volt battery sufficiently, and the batteries are more sensitive to this because of their smaller capacity. And I think it is also the case that these smaller batteries are more prone to damage when discharged. Each time a battery is discharged to the point of needing a jump/re-charge, it tends to lose total capacity. Add all that together and throw in a car that may have been used for 1 and 2 mile test drives at a dealer, might have sat for a month or two, and maybe had a battery that was not 100% charged to start, and all the sudden a lot of what we have been experiencing becomes potentially explicable. There might still be other problems behind some of our experiences, such as electrical malfunctions and batteries defective from the factory, but it seems easy to damage these batteries at a dealership and then make it worse early in the life of the car by fiddling with the accessories. Moreover, the Prius blogs tell stories of strange things happening when the 12 volt batteries are near the total discharge and/or failure point: lights turn on, doors unlock, etc. Prius owners sometime buy after market batteries from Optima as replacements. They are supposed to be more robust than the original equipment. Some buy trickle chargers, but I think this needs care in terms of warranty coverage. Something to look into. Ford seems oblivious to all this, so far as I can tell, but I expect to be talking with their customer care people again the end of the week and will discuss it with them.

I think all the accessories and computer functions run off 12 volt power. The Lithium battery is high voltage.

Another c-max forum with battery complaints: http://www.greenhybrid.com/discuss/f81/any-solid-details-cmax-27953/index2.html I will crosslink a note about this forum on that forum. . . but getting registered there is a problem. there's a bug that needs the forum administrator.

SE with 201A package (parking assist, power trunk lift, ambient lighting), 160ish miles, 12 volt dead in morning after 1 week of ownership [some notes for people keeping count: Remember that people who had battery problems in past months may have posted on other threads but may not still be reading this forum and may not add their details to this thread. Also, there are a few dead battery reports on non-battery related threads on this forum and also other websites, and there are probably many more people who have had battery troubles who have not posted anything on the web. "Battery trouble" is being used loosely to stand for shut down of the 12 volt electrical system; we are not yet sure whether the battery is the cause of the problem.]

Jeffrey Please call Ford customer service and let them know you had this problem. I have listed the number on this and the other dead battery thread. Calling them will help us all. The number of cases will not only get attention but also help to diagnose the cause of the problem I think there are cases involving SEL models on both threads.

I think that was pitch perfect, very shrewd, and 100% true.

And I am just back from the dealer, too. They had my car since the 26th. The service adviser signed it out, but I went to speak to the sales manager and then the owner (2nd or 3rd generation of the family that owns this dealership) joined us. Based on the test results that did not show anything and my reporting of what has happened with other cases, they decided to change out the 12 volt battery. I made sure they understood that in at least one or two cases posted on this board there was a changed battery and then a re-occurrence, and that even in those cases it could still be that bad batteries could be the cause - they understood and felt it was better to try something. As I was driving off I finally got a call back from Mark Coll, a West Coast customer care service manager from Ford. He is not a mechanic or repair manager, but works in customer service and is a liaison between Ford and dealers and customers. He was apologetic and promises to discuss the matter with a technical adviser (a mechanic) who will have access to national reports from dealers and from Ford engineers. He will try to contact the engineer who has worked on mbedit's car in Wilmington, NC, and also will ask whether the jump start A) might erase system memory of a trouble report and/or B) might reset a safety switch that could have shut down 12 volt power. Mark Coll said Ford is keenly interested in tracking & solving problems with its new hybrids, obviously because it is betting a lot of future business on them. I believe him because this is the future of their business. They need the cars to succeed. He will get back to me at the end of next week. There will be some delay in gathering information because of the holiday. Last, Mark Coll also said he is thinking there maybe should be an advisory to have roadside service tow cars that have no 12 volt power rather than jump them, so that service departments can see them when they are not working. I think having cars towed to the dealer is the right thing to do. Any good dealer should cover taxi and/or car rental costs under such circumstances. A few more notes: My dealer's meter for checking power draw only works until power shuts down, which is normally 10-15 minutes. They do not have Ford equipment capable of a longer test for a power draw, so I wonder how mbedit's service people did it at their dealership. That would be great to know.

If the battery dies again I think the best thing to do is have roadside assistance tow it to the dealer so they can see it with the electrical system down. Clearly there have been a bunch of owners who have experienced the same problem we have experienced, and an unknown number more who do not post on this forum. Personally, I think it is important to log the problems with the Ford dealerships and with Ford's corporate office. The degree to which this is a common problem could well be a clue to identifying the cause and finding a solution. The problem has happened to so many people that I've got expect it will happen again to you and to all of us until the cause is clearly identified.

When I get my car later this morning I am going to try to pump my service manager for details about their diagnostic program, how long they hooked a meter to my battery to check for power draw while the car was off, etc.

New day. Back on the phone with Ford cutomer care asking why I haven't heard from them. I got the name and number of the manager I have been assigned and left him a voice mail message. He is due at the office by 10AM. Unfortunately this means I will be picking up my car today with no discovery of the cause of the 12 volt problem. Please post full details of what your dealerships test, what results they get, and what they change or correct to try to solve this problem. And please call Ford customer care and write letters so that Ford hears there is a problem.

Yes, we need to collect information, share it with each other, and each of us needs to call & write to Ford and keep careful records. Ford's best interest is to resolve the problem ASAP.

service manager just called me. he called Ford's hotline and they told him 1) if no trouble codes are stored in the engine's computer then the DC converter is working properly and the hot line advises against any further tests, and 2) the hot line said they had no records of any similar cases. Tomorrow I will pick up my car and drive it, hoping I don't get stuck with a car that does not start at an especially inconvenient time. If/when it does not start, I will have it towed to the dealership rather than jump started so they can see it in the non-functional condition. I will also follow up with Ford's customer care office. Mbedit's case with the Ford engineer would be especially helpful to know more about so that we all can document that Ford knows there is a problem. I would not yet say that Ford has crossed a line in refusing to acknowledge a manufacturing/design defect, but this is obviousy goign to take more work on our part, and more bad experiences of cars with dead batteries. If the problems continue and Ford is not forthcoming with a solution, then the car will develop a bad reputation fast. It is in Ford's best interest to solve a problem like this ASAP. Of course the real world does not always work that way.

Please keep us posted and pump your service department for details about everything they test. Tell your service dept to call the Ford hotline for tech help. They will have the number.. The Ford customer care number is 800-392-3673.

please let us know what your Ford service mechanics do with your car. as i explain on the other thread, my car was given a battery test and charge, then today a draw test to see if current is being drawn when the care is off. Didn't find a problem. Next they are going to try to test the converter that converts high voltage from the Lithium ion battery to 12 volt dc current to charge the 12 volt battery. please keep us all posted and please call Ford corporate customer care to let them know have had this problem.

mbedit please provide more details. If the draw is not constant, how often does it happen? How long does a meter need to be hooked to your car to catch the spike? Does the spike happen at regular intervals or randomly? How big is the draw at its high and low points? are you able to share the name of the Ford service engineer who has been sent out for the case? thanks. this information might help me and others

Thanks for this helpful suggestion. Wouldn't a "leak" of this kind show on a draw test as current being drawn from the 12 volt battery after shutdown? Or are you suggesting this leak/draw is happening when the car is on, so that the 12 volt is being depleted more than being charged?

update- service manager called Ford's service hotline where he was told to do a draw test. The meter showed a draw of 2.3-2.4 amps at engine shutdown that then reduced to .01-.02 amps after about 10-15 minutes and stayed at .01-.02, which is normal. I then asked the service manager to test the step down converter that converts power from the high voltage battery to 12 volt DC to charge the 12 volt battery. He said he would call the hotline, ask advice, and test the converter. I am glad the service manager is making this effort. Still waiting for Ford's corporate customer service to call me back as promised by 3PM today. Just about 3 now.

My car operates with a key as do several of the others that have experienced dead 12 volt batteries. No chance of our having left the car turned on by accident.

thanks for the post. yes, a rudimentary check if the service manager and/or mechanic are plugged in.

yes, hybrids generally charge the 12 volt battery with a step down converter that converts power from the high voltage battery. seems like one of the first things to check after bench testing a battery.