CMax-Traveler

1) Yes, the 2013 had the "mileage upgrade" 2) The numbers are from the dash readouts, but the two fill-ups which make sense the dash was 2.5mpg higher than the pump. 3) I used the A/C on the return trip, which was pretty consistent with last year's trip. Here's my fuelly. I gave up on tracking the 2013 last August. http://www.fuelly.com/driver/cmaxtraveler It's possible this trip was a fluke, but there wasn't much wind. With as many times as I made similar trips in the 2013 year you'd think conditions would've been similar on at least one of them and I never achieved higher than 45mpg highway. Note the highway driving was entirely on eco cruise. But good point, little things make big differences when you're this high in the MPG range.

Hey everyone, I have an interesting anecdotal report here on the difference between the 2013 and the 2015. I frequently drive from Boston up to the White Mountains to go hiking. I also recently traded up from a 2013 C-Max to a 2015 C-Max. I did so this past weekend, with some interesting results. The trip, overall, was about 290 miles, and involved 80-90% highway driving, mainly at speeds of 60-70. I made this exact same trip several times last year in my 2013. In the 2013 C-Max, I never got better than 44mpg on the round trip, and was usually in the 42.5-43mpg range. In the 2015 C-Max, the trip this weekend ended at 50mpg for the trip (I made a similar trip earlier this year which resulted in 46.5mpg, but that was with only 400 miles on the car - I now have 2700 miles). Needless to say, I'm quite impressed with the changes made between the 2013 and the 2015. Every tank since I got the car has been a 600+ mile tank and I haven't drained it empty (except the first tank; the car wasn't topped off at the dealer). Just thought I'd share!

Actually, this "battery low" condition you mentioned is different than the 15 minute power bus mentioned by drdiesel1. I've experienced it myself several times. I don't recall if I had the car in accessory or if it was off, but whichever it was, after sitting in the car having the radio on for a few minutes, apparently it's able to detect that the charge on the 12v is too low, and the 4" center display flashes a message about "battery too low, powering off", and then powers off the radio. This was much shorter than the typical 15 minutes you're given, after which things just power off with no message. When you flip the key on to re-engage the radio, it also re-engages the DC-to-DC converter, thus recharging the 12v battery.

USB has two data pins and two power pins... the LEDs I've seen on thumb drives are powered by the power pins, regardless of the data - and then flash upon data usage. Not knowing anything about how it's actually set up... is it possible that the power pins are connected directly to the battery rather than switched via the APIM?

No, I can't do long-term monitoring. But my point was that it's not a constant parasitic load, and a standard parasitic load test won't help. It's some module that randomly comes on and stays on, and that would require a very extended, nightly, parasitic load test for potentially months until the problem recurs -- and it would require much more patience than any of us have. And then, once it does happen, good luck figuring out which module it was, since the car will have died and all you have left is a log of the current draw - not what was drawing it -- unless you also come up with a way to be notified on one of those random nights when it happens so you can go and pull fuses until it stops. Those results are pretty awesome, but not surprising - things are constantly waking up and going back to sleep, as evidenced by all of the buzzing, whirring, fans, etc. that have been documented. Some of the things I'm pretty sure it does is opening/closing the grill flaps, cooling the HV battery, maintenance on the fuel system pressure, and others. I'm assuming Ford has a bunch of C-Max'es with known problems in a lab somewhere with similar test equipment hooked up to try and trace this problem - and if they don't, they should. I know from my experience that 5.7 is too low to energize the car. But I also know that, in the months I've been monitoring my car, other than the morning that it didn't start, I've never seen the "resting" voltage drop below 12.3v. So I don't think it's an issue of the charged state gradually falling until it's too low, I'm pretty sure it's a sudden thing - something turns on and gets stuck on that drains it. I genuinely wish Ford luck in figuring out what, though, for all of our sakes!

My dealer told me: Many many C-Max 12v batteries were replaced that were not bad, just because they had discharged. As a result, Ford instituted a policy that the batteries must be tested thoroughly and fail before a replacement would be approved. But even after that, a large (but smaller) number of 12v batteries still tested as failed and needed to be replaced. As for the underlying cause as to why they've tested bad, I have no idea. Bad batch? Unlikely. Discharged too often? Perhaps. Something else? ?? Realistically, only Ford can know this by testing the failed batteries. Yep, that's 100% accurate - many of the problems that people have concluded are the problem should mean everyone would have the problem. But there are many other factors that could contribute: the way the car is driven, the frequency and duration of trips, whether it sits unused a lot, the environmental conditions, manufacturing differences in the cars, bad batch of radios, etc. ... and whatever those factors are trigger a specific set of circumstances causing the various types of problems people have encountered, and causing the vast majority of owners to have no problems at all. We're all grasping at straws here, and sadly, it seems at the moment that Ford engineering is as well.

As I mentioned in my post, my meter has a specified resolution of 400A +/- 0.1A - so in theory it can measure down to 100 milliamps. In practice, I'd say I can distinguish between 200milliamps and zero, but probably not less. When my car is fully "asleep" the meter reads 0.1 or 0.2 amps. Which is around the smallest load it can detect, but it's definitely negligible. The 12v battery in the C-Max is rated at 40Ah. Which means that with the smallest load detectable by my meter, the battery should not discharge fully for over 200 hours. Even if we say my meter can't accurately measure less than a full amp, that's still 40 hours. In my personal experience, my 12v battery discharged in less than 9 hours. That would indicate either a battery that cannot hold a charge (but it passed all tests at the dealer), an undercharged battery (but it indicated ~80% charge at 1am prior to the discharged condition at 10am), or a parasitic load of at least 3-4 amps. Which would be easily detectable by a non-Micro meter. So, my meter can detect a parasitic load that would be required to drain the car in the observed duration, and I have not witnessed any load of that magnitude.

I'm not aware of any cases where the DC-to-DC converter software update solved things. If I remember correctly, the DC-to-DC software update TSB (13-5-1 and 13-6-23) was initially targeted at resolving a cold weather problem, where the 12v wasn't receiving sufficient charge in cold (below freezing) weather when being run for short periods of time at high electrical load. I think they may have eventually updated the TSB to apply to all temperature conditions, not just cold weather. My question was more whether or not a problem still remains there. The DC-to-DC converter plays the role of alternator in the C-Max, so it's unique to hybrids. Because we don't have a starting load requirement, they're smaller batteries than most cars. Under regular use, from my voltmeter monitoring, the DC-to-DC converter seems to maintain a SoC around 70-80% -- which, over time, will result in sulfation (and thus, failure) of the battery. In my car, I've had two problems. One, a good battery ends up drained for no reason overnight - likely a module turning on and staying on, thus draining the battery. So, that problem is still out there. But the other problem is I've had two 12v batteries go bad and need to be replaced. And it seems a LOT of C-Max 12v batteries have gone bad. It has been blamed on a bad batch of batteries - but so many, produced over such a long timeframe? I'd be more inclined to say it's the C-Max causing them to go bad b/c of maintaining an insufficient state of charge. Now, disclaimer: that's just speculation; I'm not an engineer; I don't know that much about car batteries, and I don't have any direct evidence to back that up... so I'm just fueling Internet rumors here. But it seems to me to be a better explanation for so many bad batteries than I've seen anyone else come up with. I'm not sure how to test that, though, besides going through and examining all of those dead 12v batteries - which I hope Ford is doing. So... thoughts? They checked that the last time it was in; it appeared to be fine.

Jus - you hear the battery ventilation fan on well over an hour after you've powered off the car? I've heard mine on, but usually only for a few minutes after I leave the car - not hours later...

dmk, It has been suggested in the past that the ventilation for the battery coming on and not turning back off might be a problem. I've wondered if that's an issue, too, as all of the problems I've had occurred when the overnight temperature was within a certain temperature range - low 50's (which I think is what it was last night in NJ)... but not every time it's in that range. As far as I know, nobody has determined that for certain, and there are no TSBs from Ford to that effect... yet. The thing that doesn't make sense to me is: if that were really the problem, it would probably be a software issue, and would apply to all C-Maxes, not just a few. So who knows. I'd recommend an experiment - if you notice it again, leave it alone and see if it's dead in the morning. Not a great solution, but it would definitely be an excellent clue. I'm curious - how did you test the 12V voltage? Did you disconnect the battery, or did you test it live? If it was live, it's likely that you weren't actually testing the battery voltage, since the car woke up when you opened it so there would've been a current draw... and I believe the DC-to-DC converter would've immediately started charging if it were low (although I'm not certain of this). Anyway, great thought, and I'm curious to hear any additional info from others.

I'm not sure if this has been posted, but here is the 2014 car complaint index: http://www.lemonlaw.com/carcomplaintindex.html A couple things to note: This is a RELATIVE index - so it's number of complaints relative to the number of that vehicle sold While C-Max is on the list, it's nowhere near the top. It is about 1/3 of the worst car, and just barely worse than the Prius. Anyway, there's some hard data for ya.

Here's the method I followed for testing for a parasitic load: 1) Open the rear liftgate, close all the doors, lock the car, then manually latch the rear liftgate by closing the lock mechanism with a screwdriver, so that the hazards blink once. This makes the car *think* it's locked and closed, but gives me access to the rear compartment - the hazards blinking once confirms the car believes it's sealed. In theory, the car should eventually go to sleep on it's own, but I did this just to be certain. **WARNING** For anyone else trying this, be sure to unlatch the liftgate before closing it by pressing the open button, or you could damage your car!!! 2) Remove all of the rear battery covers, to give access to the 12v battery. 3) Clamp a 12v ammeter around the battery ground cable (the thick black one going from the battery to the floor of the car). 4) Wait until the car is asleep - 10 minutes or so. 5) Read the output on the ammeter. Wait several hours, read again, etc. etc. etc. My results were: * Unlocking / locking the car generated a draw of 12-16 amps. * Having the car unlocked and the hatch open there was a draw of around 5-6 amps. * Having the car locked and all lights off, there is a draw of around 2-2.5 amps while the car is not in sleep mode. * Once the car goes to sleep, the current draw falls to 0.1A. Checking it for several hours after it's asleep, I've never managed to witness anything above 0.2A, but unfortunately my ammeter goes to sleep after 15 minutes so I can't monitor it continuously via a camera feed or anything like that. Note: The resolution on my ammeter is 400A +/- 0.1A so we're right at the edge of its capabilities, but regardless, 0.2A shouldn't kill a good battery overnight. Rob - in theory, the car should go to sleep after 10 minutes, regardless of whether the doors are open, closed, locked, unlocked, etc. But since I don't know how it's actually programmed, I'd rather be safe than sorry, for testing purposes. There have been anecdotes of people having more trouble who leave their cars garaged and unlocked, but there are many others of us who lock it regardless, so I'm not sure it matters. But, since I'm in a testing mood, I'll test it out now with my ammeter and will report back. EDIT: Yes, the load on my car did fall to 0.2A after about 15 minutes, despite being unlocked. So it does appear to go to sleep regardless, at least in this particular instance.

Just a note that I added a fairly important comment to the end of my above post, for anyone wanting to replicate my methods.

Adam, your problem sounds a bit different than many of the other problems encountered... yours is the first I've read about where the car didn't die overnight. Which makes me think it's likely a water intrusion problem with the electrical connections, since that would kill the 12v battery quickly and repeatedly, and yet the battery would still test good. Especially since the dealer washed the car shortly before this started happening. If it's a constant parasitic draw, the dealer should be able to trace and find it fairly easily. And... if it is water intrusion, I could in theory see how that would prevent the car from being jumped, since that's essentially a short in the system. The only additional thing I'd be concerned about is, once they find the root cause of your problem... even though the 12v tested good, since it will have died so many times, it's likely that the 12v itself will sooner rather than later fail to hold a charge, and need to be replaced. Keep us posted, good luck.

RobMax, sorry for the delay here, I've been away from the forum for a few days. I have one of these devices plugged into the 12v socket in the trunk compartment (the one that never powers off). It gives a constant readout of the current state of charge of the battery. The current draw from that device is on the order of a couple milliamps (yes, I've tested it), so it won't drain the battery. Since we have people on here telling people they're wrong and insulting them, essentially telling them that they aren't capable of understand what's wrong ... (ahem) ... I'm going to attempt to explain things. -- With the 12v battery, in non-technical terms, there are two things to be concerned about: State of Charge, and Ability to Hold a Charge. The voltmeter tells you the state of charge. You can't tell the ability to hold a charge without fancy testing apparatus or a lot of patience. In theory, a battery that is going bad could be reading 12.5v one minute, and then a few minutes later could drop to 5.0v despite having little to no load placed on the battery -- that's the ability (inability) to hold a charge. When a C-Max goes into the dealership with a battery problem, Ford has instituted a procedure that the dealers must perform a rather expansive test using their battery testing equipment to determine the battery's ability to retain a charge. If the battery fails, replace the battery. If the battery passes, search for other causes. Another problem is, with every time a battery is drained, its long-term ability to hold a charge is substantially reduced. So, for a car that's persistently encountering a dead state, even if the battery is initially good, it will go bad quickly. -- salman - I'm not entirely certain about your statement about the problems not being due to the charging routine or the batteries. One of the updates performed on my C-Max was a software update to the DC-to-DC converter - the module that charges the 12v battery from the 120v battery. I also noticed that the last time I had my car jumped, the car clearly extensively charged the 12v battery (you could see the added load on the 120v system on the dash gauges), and then for several days the "resting" state of charge was around 12.9/13.0v - but several days later it fell back to 12.5v. So I'm wondering if perhaps there's a problem in the way that the car is charging the battery, or the state of charge that it maintains, which is causing batteries to fail. Just speculation, who knows. In my opinion, based on everything I've read on the forums, there are many different underlying problems for this issue. One was the SE's radios not turning off. Another was the water intrusion. Another was addressed in that software update as a part of the recall. And there are others I'm not recalling. And there's still at least one (or more) cause that remains unknown, which Ford Engineering has stated somewhat publicly that they're still working on a solution for. For some people, replacing the battery from the bad batch that Ford got solved the problem. For others, replacing the radio solved the problem. For others, replacing the fuel pump or wiring harness where water intrusion / corrosion was occurring solved the problem. But for an unlucky few of us, the problem remains. -- Just so this is out there... when I encountered my last dead battery, when it went from 12.5v at 1am to dead at 10am, I took the car into the dealer, and my 12v battery passed all of the "ability to hold a charge" tests. So, as far as Ford is concerned, my 12v battery is good - it can hold a charge. So something else killed it overnight. As I mentioned, it didn't rain and I didn't wash my car, so it's not a water intrusion issue -- my radio isn't in the affected batch -- all my software is current -- and the dealer checked and cleaned all of the fuel pump connectors and other connectors that have shown signs of water intrusion, and they were fine. The dealer essentially shrugged, said they checked everything and it looks good, and sent me on my way, wishing me luck. Not especially satisfying. So. In summary. In my specific case, where we've ruled out the other known problems. *IF* my 12v battery can hold a charge (which, according to the testing, it can), and since the state of charge was acceptable at 1am... and the connectors weren't shorted out due to water intrusion... and the radio isn't bad... the only option remaining is a there's parasitic load that very intermittently occurs, for some as-yet-unknown reason. I've performed my own parasitic load test on the car, and under normal circumstances, there is no parasitic load. So there must be some module, somewhere, that very infrequently turns on and gets stuck on, causing the battery to drain. And catching it in the act is next to impossible for a layperson, because of how infrequently it occurs. -- If there's anything wrong in anything I said above, please let me know -- I want to understand the underlying causes and fix this problem once and for all. -- EDITED 8/29 11:30am Eastern TO ADD: One thing I did neglect to mention... In order to accurately test the state of charge of the battery while it's still in the car, the car needs to be in "sleep" mode. There can be little to no drain on the battery, and the DC-to-DC converter needs to be inactive. The car goes into "sleep" mode approximately 10 minutes after it's locked (and the lift gate is closed), and wakes as soon as the doors are unlocked. So this means the only way to accurately check the voltage on a 12v voltmeter plugged into the lighter in the back is to look in the windows before unlocking the car and after it has gone to sleep. Anything else and you're likely not measuring the actual state of charge of the 12v - you're instead measuring the results of the charger or a battery discharging under load, neither of which are accurate.