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Side Note:  My commute has very small hills, which rarely require the ICE and a few opportunities for regen.  Therefore I spend a lot of time with the EV battery low or depleted.   I'm also stingy enough to just pop on the heated seats and leave climate control off in the morning, so the EV doesn't get this charge time during the start.

 

If the converter shuts off when the EV is low, this could be a huge contribution to my 12V problems.

 

That being said, I have started using the ICE to start out more from stops, saving the EV for maintaining speed later.  This leads to better mileage for me and a generally fuller EV battery while in progress.  

I was pleasantly surprised to get 56 MPG out of a 50 mile round trip today.  Time will tell if this keeps the 12V system topped up better.

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Regarding number of miles traveled in a day: my commute is 9 miles to and 9 miles back.  That's pretty much my driving pattern for the week, with a few miles in town.  I've not had any problem with my battery dying.

 

BTW: one of the engineers at the Invine gathering told me that people at Ford DO monitor this forum.

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It seems like the Energi hasn't been subjected to failures the way the normal hybrid has been, so I think you'll be fine!

 

I was driving with a friend this weekend who knows all the issues I was having, and his comment was that he still really likes the car, as do I. Overall, the head room, the low noise, and zippy nature of the C-Max are worth the few MPG's over a Prius to me.

 

I'm still concerned the issue to could re-manifest its self on my replacement, so I want Ford to figure it out!

 

Ford told me they are also comparing my current model (via the VIN) to the one they bought back to see what the differences are in software since I'm not experiencing the issue (yet! knock on wood!) on my replacement.

 

So It seems they are focusing on software at the moment.

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Hi all - I just did a quick test with a DMM on our Energi today.  Last night, after driving for the day, the 12v battery was at 12.42 v, this morning, the voltage was at 12.23.  That, after replacing a blown 20A fuse for the 12v center console accessory ports that went out the day our battery died a week ago.  Odd thing is, we had had no accessories plugged in when it blew.  I'll look for a suitable cap to cover the 12v port inside the cosole when not in use.

 

With the DMM still attached, I hit the push-button to start the car, and the volatge immediately jumped to 14.6 volts.  So it definitley charges from the HV batt whenever the car is on.  I'll have to try it with a depleted HV battery to check out if that holds true for a battery-depleting trip.  Then, I shut the car down, and voltage dropped to 12.3 v (only on for less than a minute), then plugged the car in.  No change in voltage.  So, confirmed that the 12v battery does NOT charge and is completely disconnected from the HV battery when the Enegi is plugged in and charging.  So, yes, the Energi can be susceptable to the dead battery syndrome, and plugging in at night won't help.

 

I also verified that the 12v center console accessory ports do indeed power down after the battery save time has elapsed.  So I'm not so sure we can use those ports to hop (jump) the car if the 12v batt is dead. I can't turn an ignition switch to activate the accessory ports - only a push button.  And the only "always on" 12v port is in the rear, which won't open if the 12v is dead.  Have to open the hood.

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It's easier to catch the sun on my dash, but the only port that stays open is in the back.  Good thing my solar panel came with a really long cord.  And yes, the other ports are worthless if you need a charge.

 

I bought a 2A 12V charger for 30 dollars today and plugged it into the rear port.  I went from 12.2 to a full 12.6 in a couple of hours.  I wasn't watching close enough to see how long it took.  Less than two hours.  Charger says full and multimeter reads 12.6

 

Looks like my battery is still in pretty good shape.

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Good testing, Oakland. I guess I was wrong.

 

But if charging the Energi doesn't also charge the 12v battery, then it seems less likely that the DC/DC is simply undersized for light driving. Our typical short drives must be enough to keep the battery charged, even with the additional load of keeping the car active while being charged. That points back to a defective something causing additional load on the 12v batt, rather than a design defect not letting it charge enough. Which is a good sign, it means that the broken cars can be fixed, and the rest of us won't have problems.

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If my hunch about the converter shutting down when the EV battery is low is correct, then the Energi would be much less prone to 12V problems.  

 

The 12v would be charging the entire time you were drawing off the EV battery after a full nights charge.  If you didn't plug in regularly to make this so, you would have problems.

 

I'm not sure taking the EV battery out of the loop when it gets down to the minimum charge can be fixed to only keep the converter on. It would depend on where it is wired.  I can tell you that they don't want to take the EV battery beyond a certain minimum so it makes sense to shut even the converter off.

 

On this subject, why does the hybrid save the bottom 25% ?  Under what circumstance would I want to keep this?  It seems I could get better efficiency if I had this extra battery to use.  Why let me use it some times and not others? Would it damage the battery if I used it all the time?  It seems like a strange holdover from the Energi's programming being applied to the hybrid. It's reminiscent of Spinal Tap having an 11 on their amps. (If 25 is really 0, just make it 0.)

 

Would allowing the bottom 25% of the EV battery to be used fix the 12V problems?  And would it increase efficiency?  Get on it Ford.

Edited by Max Power
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There is a minimum state of charge that must be maintained on the HV battery. Below such level voltage drops considerably. The HV battery is used to start ICE via the electric motor. So, you wouldn't want the charge level to fall below the minimum level + charge needed to start + a reserve. That minimum operating level could easily be 25% of the HV hybrid battery capacity. So, when driving ICE will start at the that minimum operating level to recharge. If you use the HV battery after shutdown, there's the risk that the charge would be so depleted as to not be able to start ICE.

 

 

I have been monitoring 12V voltage since I became aware of ET mode. I've seen readings between 13.8V - 14.4V. IMHO, that appears to be very poor regulation by the converter. The minimum voltage on a lead acid battery when charging should be above 14 V normally. I've also seen my battery voltage be between 12.2 V - 12.6 V shortly after shutdown and the next morning. My car has always started. Again, something is amiss.

Edited by Plus 3 Golfer
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There is a minimum state of charge that must be maintained on the HV battery. Below such level voltage drops considerably. The HV battery is used to start ICE via the electric motor. So, you wouldn't want the charge level to fall below the minimum level + charge needed to start + a reserve. That minimum operating level could easily be 25% of the HV hybrid battery capacity. So, when driving ICE will start at the that minimum operating level to recharge. If you use the HV battery after shutdown, there's the risk that the charge would be so depleted as to not be able to start ICE.

 

 

I have been monitoring 12V voltage since I became aware of ET mode. I've seen readings between 13.8V - 14.4V. IMHO, that appears to be very poor regulation by the converter. The minimum voltage on a lead acid battery when charging should be above 14 V normally. I've also seen my battery voltage be between 12.2 V - 12.6 V shortly after shutdown and the next morning. My car has always started. Again, something is amiss.

 

 

I understand the concept of not wanting to fully discharge the HV battery.  Why does it let me use all of it some times while driving and others not?

Edited by Max Power
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I'll try to be more clear.

 

First, all C-Maxes track your routes and know where you are.

 

When I am near home or somewhere familiar, the HV battery is allowed to discharge below 25%

 

This would make sense in the Energi since the car figures I can plug in before I have to drive again.

 

This makes no sense in my hybrid since I can't plug it in.  If it is safe to use this battery in the hybrid, I should be able to use it all the time.  If it isn't safe, I should never be allowed to use it.  Is it or isn't it safe?

 

Where is the true bottom of the battery?  Is the hybrid keeping more in reserve than it should, which could coincidentally be kicking off the converter too?

Edited by Max Power
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There are likely many variables that go into how low the PCM allows the battery to get to before starting ICE like rate of discharge for example .  At 60+ mph in EV mode the rate of discharge will likely be higher than when nearing home at slower speeds.  I've seen the battery indicator level as low as 10% or maybe slightly lower when near home but on the highway I'm not sure I've seen it below 20%.  It's just the way the control logic is set up.

 

Also you can use Engineering Test Mode to view 12 V battery voltage.  You can also charge the 12 V battery via the HV battery at home.  First to check the battery voltage, start ETM but do not step on brake pedal when starting .  You will not get the ready to drive message.  Scroll to the battery voltage on the ETM screen and you'll see 12.X volts.  The HV battery is not charging the 12 V battery.  Now, step on the brake and then start ETM again.  Now when you will see that the 12 V voltage is 14.X volts and you will get the ready to drive message. The HV is charging the 12 V battery.  This will likely time out after a while.  I haven't tested the time before timeout though.  But just a few minutes should be enough to increase the 12.X V somewhat.  I see no reason one couldn't repeat this multiple times to get the battery voltage to near 12.5 - 12.6 V.

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I'm specifically talking about the EV+ mode in the hybrid.  This has a tendency to keep the car in EV when you near home, even taking it below the normal hard stop for the HV battery. If it is okay to take the HV battery into that range, I want to be able to do it all the time.  I would like to have the control myself, not have it be based on location.  What is the purpose of the EV+ mode in the hybrid?  It seems like a remnant of Energi's programming that is being left in the hybrid.  Should probably start another topic about that but I included it here since it may have an effect on charging.  

 

So far I haven't seen any readings below 14.9 while driving so it appears that the charge is always being applied.  The issue could be that the accessories are just too greedy.  FORD went with conventional bulbs in a quite a few areas.  Is this the reason many other hybrids have LED tail lights?

 

The car loses .2V overnight and my commute returns .05 each way.  By the end of the week, the battery looks pretty crummy.  I am going to see how much using the solar panels captures while I am parked at work. I need to do this for the whole week before I know it will keep up.

 

The technique you mention is intriguing and could work in a pinch if one knew ahead of time that it was needed. I have a real problem with the fact that the car knows my battery is reading 11.9 and isn't telling me that information.  This may be the biggest flaw. Leaving my car on for an hour didn't charge the battery fully, with nothing on in the car  What makes you think this is more efficient, or are you saying that?  The time it takes to timeout would be very helpful information.

 

Extending your idea, the solution is probably to rework the software so that the HV stays connected and the converter stays active for 1/2 hour after you shut the car off  when a low 12V is detected.  This may be difficult for them to program and there may be liability issues with leaving the HV connected while the vehicle is unoccupied.  Ford may have the solution from the programmers but need approval from legal to implement it.

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I know you are talking about EV+ mode but in other instances like on the highway it's good to have extra battery capacity in case of an emergency.  When ptjones intentionally ran out of fuel, he was able to drive to a gas station.  What if the engine failed to restart while traveling 60+ mph in heavy traffic when the battery supply was virtually used up.  I doubt Ford would want to comprise safety.

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I know you are talking about EV+ mode but in other instances like on the highway it's good to have extra battery capacity in case of an emergency.  When ptjones intentionally ran out of fuel, he was able to drive to a gas station.  What if the engine failed to restart while traveling 60+ mph in heavy traffic when the battery supply was virtually used up.  I doubt Ford would want to comprise safety.

 

I'm sure that is exactly the reason.  I'm saying it isn't my preference that it would be that way.  I'm responsible enough not to run out of gas and ptjones was able to show that the low fuel warning is 35 miles too cautious.

 

Why sacrifice MPG, for a reserve that I will never need?  I never needed a reserve for my conventional gas vehicle.

 

How is running out of gas any less convenient when I am near home?  (The vehicle knows the fuel level, it could take this into account)  It took roadside assistance quite a long time to get to my house when my battery was dead,  whereas highway responses in other vehicles have always been quick.

 

IMO, Ford needs to hear these things and adjust the software.  I guarantee there are MPG gains to be made that require nothing but software updates.

 

EDIT:  started new thread about EV+ mode in non-plugin.

Edited by Max Power
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Hi My buy back claim is still at Ford corporate. The customer service rep said 5 to 8 (I assume business) days. So I might hear something tomorrow. Otherwise it's just me and my Corolla rental. Cheers Andrew

 

Well keep us posted.  Going to Eureka... but not in my C-Max.

 

Marty

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A search for C-max battery problems turned up the following from a British C-Max owner.  It appears this was a problem nearly 4 years ago.

http://www.cmaxownersclub.co.uk/forum/technical-39/dashboard-lcd-clock-draining-battery-5912/
 
07-30-2009, 02:53 PM  

"I had the alternator output checked and that is fine, the battery is only 18 months old and the supplier assures me that he doesn't get problems with these items, he really did sound genuine, very helpful chap!

Last Saturday night I locked the car to notice that the dashboard LCD display and the clock display on the Sony radio were still illuminated. I unlocked and locked the car again and they did not extinguish. I said to the missus that if the battery was dead on Monday morning, I think I might know whats causing it, sure enough it was dead.

The question is, could these two displys remaining on conceivably drain an 18 month old 62Ah battery in 36 hours?? If so, has anyone experienced this before and/or know what could be causing the problem?"

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OK, lets try this again,

Left a couple other posts out there somewhere....

Leased a C-MAX from Kemp Ford in Thousand Oaks, CA (great people) on Jan 15,2013. Dead in driveway AM of Mar 10. Approx. 800 mi.  Had AAA come out and jump and during a test he showed about 6V in the battery. Called the dealer and they wanted me in that day. Left overnight and next day said they couldn't find a problem.  Of note: the first service rep said he has not seen this before. He went to lunch and the second rep said he had seen this once before. On that one they replaced the electrics in a door (doors?) (or something like that). I noticed on the repair paper it said this:" Some 2013 C-MAX vehicles may exhibit a concern where the 12 volt battery is unable to maintain a charge, or become discharged when the vehicle is operated with maximum electrical loads for short drive cycles, and then left unattended for several hours. Engineering is currently investigating this concern.... blah, blah.... Advise customers to consider not using high load accessories, such as laptops and DVD players, during these peak load situations. Continue to monitor OASIS ( whatever that is ) for updates."

 Also when the wife was called to come get the car, the lady at the dealer said her hubby drives a lot of hybrids, and he said to use the brakes a lot to keep the battery charged.

 And, for members "oxnard" and "andrewwx". I also went to Vista to test drive the C-Max and they had to jump start it to get it going. (white one)

  lumike

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Understanding your C-MAX 12 volt battery.  The OEM battery is a Motorcraft BXT-67R.  The last 3 (67R) is the BCI Group Number.  The Battery Council  International Group Number defines its dimensions, voltage, post configuration and terminal type.  

This BCI number battery appears to be Motorcraft only.  I was unable to find another manufacturer offering a 67R battery.  

cmax06.jpg

This battery is listed as having 390 Cold Cranking Amps (CCA) and a Reserve Capacity (RC) of 65.  The Amp Hour (Ah) rating is not listed and may be about 35.  (A 2012 Ford Explorer uses a BCI Group 65, CCA-750, RC-140)

RC and Ah are not the same.  RC is a estimate of time, the number of minutes (65) a battery can maintain a useful voltage under a 25 ampere discharge at 80° F, lower temperatures mean less capacity.  25 Amps x 12 volts = 300 watt load.

 

A 300 watt load applied for 1.08 hours = 324 Watts or .324 kilowatts.  

The Ah rating for an automotive battery is usually based on a 20hr discharge at 80° F. 

For example, if a 12 volt battery at 80° F delivers 1.75 amps for 20 hours, its Ah capacity will be: 1.75 A x 20 hours = 35 AH. 

 

1.75 A x 12 V = 21 watts.  21 Watts x 20 hours = 420 watts or .420 KW.  Yes, you get more if you use it more slowly: Peukert's law.

The 2010 Fusion (and others) use a BCI Group 96R battery.  The dimensions are the similar.  An example is the Motorcraft Part Number: BXL-96R.  For this battery the CCA is 590 and the RC is 95.  This battery may not fit in the battery box I am not recommending this battery, just saying it is available.  Using this battery may void your warranty, ask your dealer.  

The 96R has 50% more capacity than OEM, but it still can be drained by parasitic loads.

When I change batteries or clean the posts, before disconnecting the cables, I connect my jump-start pack to an always-on 12v accessory port or other hot wire.  This keeps the system powered up and I do not loose programing on the radio or reset trouble codes.  I am careful to insulate the disconnected (hot) positive cable with a dry leather glove.  
Disclaimer: Read the warning labels.  Electricity is dangerous.  Wear eye protection. 

Edited by Sparky
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The 2010 Fusion (and others) use a BCI Group 96R battery.  The dimensions are the similar.  An example is the Motorcraft Part Number: BXL-96R.  For this battery the CCA is 590 and the RC is 95.  This battery may not fit in the battery box.  I am not recommending this battery, just saying it is available.  Using this battery may void your warranty, ask your dealer.  

 

The 96R has 50% more capacity than OEM, but it still can be drained by parasitic loads.

 

 

Hard to believe using the 96R would void the warranty or not fit because it is listed as the replacement battery in the specifications page of the owners manual (page 350).  In fact the only batteries listed in the owners manual have larger capacities than the battery Ford is installing in the car at the factory.  The listed batteries are:

 

BXT-96R-500 / BXT-96R-590

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Hard to believe using the 96R would void the warranty or not fit because it is listed as the replacement battery in the specifications page of the owners manual (page 350).  In fact the only batteries listed in the owners manual have larger capacities than the battery Ford is installing in the car at the factory.  The listed batteries are:

 

BXT-96R-500 / BXT-96R-590

Thanks for your info, I have amended my post,

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