Automatic battery maintenance by C-Max

[AgentCMAX]

I remember reading in this forum as well as in the User's Manual that the C-Max will occassionally do some sort of resetting (not sure if that's the right word) of the Li-Ion battery system.  I was doing some research on Li-Ion batteries and ran across this site...

 

http://batteryuniversity.com/learn/article/equalizing_charge

 

I wonder if that's what's going on during that phase.

[MSmith1915]

Lithium-ion batteries need special consideration.  Here's a pdf document that describes the process:

 

http://www.google.co.jp/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CGgQFjAF&url=http%3A%2F%2Fwww-personal.umich.edu%2F~annastef%2Fpapers_battery%2FACC10BMSsubm.pdf&ei=LbvTUNjnOKjPmgWk64GACg&usg=AFQjCNG2mSKSTFCWo7HGtMOoVi-_eD_78Q&bvm=bv.1355534169,d.dGY

 

It's very technical, but here's a synopsis:

 

Lithium-ion batteries need special protection
from overcharge and overdischarge, because if the single cell
voltage becomes higher than 4.5 V, the production of carbon
dioxide, ethylene and other gases will increase temperature
and internal pressure, causing severe battery damage or in the
worst case cell explosion, while if the voltage goes under 2.4
V, internal chemical reactions cause the cell to irreversibly
lose large part of its capacity

 

While different type of batteries are able to self equalize
by extended charging (i.e. trickle charging for lead acid
batteries), lithium-ions cannot be overcharged, and so a
Battery Management System (BMS) has to be used.

[AgentCMAX]

Thanks for the link.  Seems like a sophisticated BMS is required to carefullly charge the Li-ion batteries as well as the way the battery cells are laid out and whatever electronics/connectors that are part of that battery system so that it can properly charge each cells.

[MikeB]

I'm certain that we have a sophisticated BMS that monitors every single charge event, and tracks the voltage on every single cell. But I suspect the periodic battery maintenance mode is actually the next level of sophistication: it's a full discharge/charge cycle on the battery in order to accurately measure remaining capacity as the pack ages. Both the top and bottom charge points are measured via per-cell voltage detection, and the difference is the capacity of the pack. Doing a full discharge/charge cycle also allows the cells to be balanced at the bottom of their charge curve, rather than the top, but I don't know if that's the goal in this case.

[CNCGeek]

I agree the full charge cycles are also checking for the capacity.  It seems to me that on the C-max the gauge is relative to the last full charge/discharge cycle, but I am not sure on this since I have not had mine long enough to expect to see any drop in capacity.  On a hybrid it is not necessary to know how much battery capacity is left since you shouldn't get stranded, but not knowing it could also conceal degradation of the battery.  Some degradation of the battery is normal and expected, so does anyone know how to find our what the actual pack capacity is - is it available via the ODBII? 

 

I think monitoring the pack capacity could be valuable for comparison in different climates also.  The Leaf owners put together a lot of data on capacity loss relative to temps here.  The Leaf and the C-max have in common air cooled batteries (the Focus Hybrid and Volt are water cooled I believe), so it would be good to track our capacity loss over time to see how the C-max does.  Time will tell if the heat takes an unreasonable toll on our batteries, but I'm not sure how it would be detected by most people aside from a feeling that it was dropping out of EV sooner.

Edited January 8, 2013 by CNCGeek

[zhackwyatt]

The Leaf and the C-max have in common air cooled batteries (the Focus Hybrid and Volt are water cooled I believe), so it would be good to track our capacity loss over time to see how the C-max does.  Time will tell if the heat takes an unreasonable toll on our batteries, but I'm not sure how it would be detected by most people aside from a feeling that it was dropping out of EV sooner.

 

I could be wrong but my understanding is the battery pack in the C-Max is considered to be inside the car and the leaf isn't.

 

I mean, that the C-Max can use air conditioned cooled interior air for thermal management and the leaf doesn't have access to the cooled air.

[CNCGeek]

I could be wrong but my understanding is the battery pack in the C-Max is considered to be inside the car and the leaf isn't.

 

I mean, that the C-Max can use air conditioned cooled interior air for thermal management and the leaf doesn't have access to the cooled air.

That makes sense, what concerned me about it venting inside the car however is that with the windows up in the summer, temps could get above 140deg F which is where the HV battery will be disabled to protect it from overheating (according to page 4 here).

Edited January 9, 2013 by CNCGeek

[zhackwyatt]

I'll report back in August (I live in Phoenix). :worship:

[TED]

I've had my C Max for less than three months and am at 2000 miles. Had a dead battery when I tried to drive home from work last night. AAA got me started and was able to make it home. Noticed the regenerative icon was not spinning and the battery icon was empty within 3 miles. A friend told me about this site and what you all have been reporting about the battery issues. I called Ford's service rep and left a message that I was bringing the car in tomorrow for possible battery replacement, to please make sure they had one in stock, and I planned on picking up a rental. I never received a call back. I'll let you know what happens... . We've had chilly weather for us, but in San Diego, that means it is under 50 degrees. Cold weather should not have caused a problem. I did not leave anything on, haven't used the ports for charging a phone or listening to music, and have a key start. This is my first Ford vehicle and I am concerned a defective battery was installed. I do like the way the car handles and really enjoy having an American hybrid car.

[salman]

Ted

 

Please read the battery threads under the "Maintenance, TSB, & Recall" heading, and please add your details to those threads, esp the "roll call" thread.

 

In the "Battery Dead" thread you will find the phone number for Ford's corporate Customer Care office (also can be found by searching on the web). Please call them in addition to calling your dealer. It is important that we give information to Ford's central offices ASAP. The dealerships take some time to report problems.

 

In your case, it is very likely that when your 12 volt battery went dead and was jumped that some or many electronic data settings got re-set or scrambled. Even before the jump start, it is not uncommon for strange electrical things to happen when a 12 volt battery gets drained out (windows open, doors unlock, lights come on, etc - sometimes, not always).

 

Good luck. Read the threads, tell the dealer you know this is occurring to others, call Ford, and keep us all posted on what happens. We need the information. 

[TED]

Hi Salman,

 

Thanks so much for the information, which I will read. By way of an update, my service rep had the car all day and essentially, found nothing wrong. I did report to Ford Corporate, and the service rep said the dealer contacted them also to verify that my car or battery was not on a recall list. I cannot verify he actually did this, and was told they could find nothing wrong with any of the car's systems. I did not leave anything on or running; car was locked with an alarm (Ford subcontractor installed) in my office's garage all day when the battery died. The only thing I can think of is the Bluetooth symbol stays on after the car is shut down. I noticed when I turned the radio off. I have the Ford service number now and with my own AAA, am out driving around with less than my usual abandon. 

 

TED

[TED]

By way of an update since January 2013, I've now had two more dead batteries (3 total) and two replacement batteries. I dropped off the car and keys this last week and told the dealer I no longer felt the car was safe nor repairable. Ford Motor is now researching whether my C-Max is a "Lemon" in their estimation. I looked at consumer law Song-Beverly Act and it appears that I may get my money back or a replacement vehicle, at my option. I am planning on getting my money back. In all other respects, I really liked this car and am very disappointed.

[rfruth]

Any news Ted, also any way for the end user (me) to tell if TSB 13-05-01 – 2013 C-Max, Fusion, MKZ – Hybrid And Energi – 12 Volt Battery Unable To Hold Charge - - - has been applied to a 2014 C-Max ?