Battery indicator in Hybrid Mode

[larryh]

The threshold for the ICE on the Empower screen does not indicate the SOC of the HVB.  That threshold varies based on the temperature of the HVB and other factors.  In hybrid mode, sometimes it is less than 2 bars and sometimes it is above 2 bars.  No matter how I set the EV mode, whether I leave it on EV auto until it enters Hybrid mode, or whether I switch between EV Auto and EV later, when the car enters hybrid mode, the displayed SOC on the 2-D hybrid battery icon starts at 100%.  The transition occurs when the energy in the HVB falls below 1.5 kWh. 

Edited November 8, 2014 at 04:58 PM by larryh

[rbort]

Larry, please do the exercise I stated above and let me know as well in regards to the moment of hybrid switch over and the ICE threshold.  Next time I have an opportunity I will record a video to show what I mean if you guys still can't see the difference.

 

-=>Raja.

[larryh]

The ICE threshold is dependent on many more factors than just the SOC of the HVB.   It is what the Ford Engineers programmed it to be.  It doesn't indicate that some specific set of cells of the HVB are reserved for EV later mode.   As far as I can tell, there are no cells dedicated to a "Hybrid Battery".   When entering EV later operation, the car simply maintains the energy in the HVB within a 0.5 kWh band around the current energy level after charging it up by about 0.1 kWh.  I wish I could prevent the car from charging the HVB when switching to EV later mode.   Using the ICE to charge the HVB lowers the overall MPG for a trip. 

Edited November 8, 2014 at 06:20 PM by larryh

[rbort]

Ok then how do I explain the 4 bar drop to 2 bar suddenly versus gradually when the HVB runs out depending on whether I've used EV later or not during that discharge cycle?

 

-=>Raja.

Edited November 9, 2014 at 02:43 AM by rbort

[openair]

Poor memory? Difference between the Cmax and fusion?  Cooling seasonal weather?  Your HVB still in its settling period?

 

I am almost always having made use of EV later when I do deplete the HVB.  I just got back from a trip having not used EV later once to double test and refresh my memory of what is being discussed here.  The ev potential on the empower screen dropped from 4 bars to 2 bars and the charge level of the hybrid portion dropped just as when I do make extensive weekend long use of EV later.  In fact, due to the continually cooling weather, it dropped even faster than the last time I depleted the HVB after making extensive use of EV later.

Edited November 9, 2014 at 04:33 AM by openair

[TX NRG]

TX NRG:  Sure the battery "spec." is for 6.5Kwh in EV mode but I've only been able to pull around 5.5kwh out of it.  If I dug into the hybrid section I've used 5.7kwh in a trip I think the most I ever saw was 5.9kwh including most of the hybrid battery.

 

-=>Raja.

Agreed. I was just pointing out the differences in spec for the Energi and FFH (and Cmax Hybrid) HEV portion of the HVB pack. My 2013 used to use up to 5.4 or 5.5 kWh in EV mode but now regularly gets only 4.6 - 4.8 kWh out of it.

[larryh]

The ICE threshold on the Empower screen is determined by an algorithm invented by Ford Engineers.  I have no reliable way to determine all that it is based on.  However, it doesn't seem to be all that robust.  I don't think the program running on the car's display that shows that ICE threshold has been thoroughly debugged.  Many times when I increase power above the threshold, the threshold increases and the ICE does not turn on.  Similarly, many times when I decrease power the threshold falls as I decrease power.  Other times, when I am well within the threshold, the ICE suddenly turns on.  It is as if the car's display is not completely in sync with the real threshold.  The actual threshold must be computed in the PCM or some other module and the car's display is probably estimating the value of that threshold based on the information it receives.  I wouldn't put much weight on the behavior of the ICE threshold shown by the car's display. 

Edited November 9, 2014 at 12:39 PM by larryh

[larryh]

Agree with Ford and Steve.

 

If you switch to EV later the hybrid portion of the battery is used.  You can prove this to yourself by switching to EV later for some time and then back to Auto.  Once the main battery reaches 0%, the Empower screen will drop suddenly not gradually from 4 bars down to 2.  If you have CC on this can trigger the engine unexpectedly.  This is due to the fact that the hybrid portion of the battery was used and reused (charge/discharge) and is no longer 100% full.

 

 

When you switch to EV later mode, the ICE immediately begins charging the HVB.  No portion of the HVB is depleted.  The SOC of the HVB does not go down.  Quite the opposite, the SOC of the HVB goes up.  The SOC will generally remain higher than what it was when you entered EV later mode until you switch to another mode.   You rely on this behavior to charge the HVB using the ICE when switching modes. 

Edited November 9, 2014 at 12:33 PM by larryh

[openair]

 Many times when I increase power above the threshold, the threshold increases and the ICE does not turn on.  Similarly, many times when I decrease power the threshold falls as I decrease power.

I had assumed this was as simple as the physics of an object in motion stays in motion and an object at rest stays at rest combined with mechanical nature of electric motors and the CVT.

[rbort]

Ok, you guys just gave me answers as to why you are disagreeing with me.

 

For openair, the key statement you made was "My 2013 used to use up to 5.4 or 5.5 kWh in EV mode but now regularly gets only 4.6 - 4.8 kWh out of it."  This points to the fact that your HVB is degraded and can very well be why when you switch from HVB to Hybrid battery the drop is sudden no matter what (EV later  before or not).  Degraded batteries don't hold their voltage under load as well as good ones, I see this all the time in my line of business.

 

For Larry, your car's Empower meter does not behave accurately at all.  Mine does 100%.  Here is your key statement "Many times when I increase power above the threshold, the threshold increases and the ICE does not turn on.  Similarly, many times when I decrease power the threshold falls as I decrease power.  Other times, when I am well within the threshold, the ICE suddenly turns on.  It is as if the car's display is not completely in sync with the real threshold."  My car when I increase the power above the threshold the ICE always comes on.  If I decrease power the ICE stays off and eventually the threshold falls but that is exactly correct as the threshold is supposed to fall when the battery is being drained lower and lower due to staying in EV mode.  You have to keep reducing power with the accelerator to stay inside it and prevent the engine from coming on.  My engine never suddenly turns on if I am within the threshold.

 

Being on this forum I see there are alot of discrepancies between cars.  Some people have issues with MFM, you're having Empower threshold irregularities, there are 12v battery issues plus other things.  I've been lucky to have a car that works perfectly as expected.  The only way I can show you guys what I mean is that I need to take a video of the moment when switching from HVB to Hybrid in two different scenarios (EV later before or not) and when I get a chance I'll do that for you guys so you see what I mean.

 

-=>Raja.

[larryh]

The point is that the ICE threshold is a heuristic.  The engineers thought up a bunch of different criteria that can be used to determine how to set the ICE threshold.  There is nothing wrong with the car.  The problem is with the heuristics.  They are not consistent.  For example, when the ICE suddenly turns on unexpectedly, one of the heuristic rules now suddenly applies and causes the ICE threshold to jump.  The display shows the jump in the threshold and the ICE comes on. 

Edited November 9, 2014 at 04:07 PM by larryh

[openair]

For openair, the key statement you made was "My 2013 used to use up to 5.4 or 5.5 kWh in EV mode but now regularly gets only 4.6 - 4.8 kWh out of it."  This points to the fact that your HVB is degraded and can very well be why when you switch from HVB to Hybrid battery the drop is sudden no matter what (EV later  before or not).  Degraded batteries don't hold their voltage under load as well as good ones, I see this all the time in my line of business.

 

Except I never said that.  TX NRG did.  I still get the expected 5.7kwh in ev mode on my 2014 ford fusion.  I like how you decide your car is the one working perfectly while trying to convince others their ev later mode works just as incorrectly as your does.

Edited November 9, 2014 at 06:14 PM by openair

[larryh]

There is no dedicated hybrid mode portion of the battery.  EV Later simply holds the SOC of the HVB within a given range based on the SOC when EV Later mode was entered.  If you use an OBD II scanner, you can observe the actual SOC and energy in the HVB.  SOC ranges from 100% down to about 14.5%.  Energy ranges from a maximum of about 7.2 kWh down to about 1.0 kWh.  The ICE will turn on to charge the HVB to prevent SOC/energy from going any lower. 

 

The actual SOC is different from what is displayed on MFT, which ranges from 100% to 0%.  When the actual SOC is above 96%, the displayed SOC by MFT will be 100%.  When the actual SOC is 21.5%, the displayed SOC will be 0%.  This is the point at which the car enters Hybrid Mode.  The Hybrid Mode 2D battery icon now displays a SOC of 100%. 

 

The car will always enter Hybrid Mode when the actual SOC falls to 21.5% and the 2D Hybrid Mode HVB icon will then show 100% SOC.  The actual energy in the HVB will be around 1.5 kWh.  When the actual SOC reaches 14.5% (the minimum possible actual SOC), the SOC shown on the 2D HVB icon will be around 15% and the energy in the HVB will be about 1.0 kWh.

 

Note that Ford uses the following alternate names for the different EV modes:

 

1.  EV Now = Charge Depleting Mode

2.  Hybrid Mode = Charge Sustaining Mode

3.  EV Later = State of Charge Hold Mode

4.  EV Now = Locked Electric Mode

Edited November 10, 2014 at 12:49 PM by larryh

[Hybridbear]

The car charges the HVB to a maximum of about 7.2 kWh.  As soon as the energy in the HVB drops to around 1.5 kWh, you enter Hybrid Mode.  In Hybrid Mode, the energy in the HVB ranges from about 1.0 to 1.5 kWh.  The car will not let the energy in the HVB drop below about 1.0 kWh. 

Thus, your available energy in hybrid mode is about 0.5 kWh. In my experience driving in EV Later the car allows a similar level of fluctuation, about 0.5 kWh.

 

Ok then how do I explain the 4 bar drop to 2 bar suddenly versus gradually when the HVB runs out depending on whether I've used EV later or not during that discharge cycle?

 

-=>Raja.

Another thread details many examples of sloppy computer programming in these rolling computers. This seems to be yet another example. If you use Torque you can see that the max discharge limit gradually decreases and doesn't rapidly decrease when you enter hybrid mode like the Empower display may indicate. Larry also provided an excellent explanation which is quoted below.

 

The ICE threshold on the Empower screen is determined by an algorithm invented by Ford Engineers.  I have no reliable way to determine all that it is based on.  However, it doesn't seem to be all that robust.  I don't think the program running on the car's display that shows that ICE threshold has been thoroughly debugged.  Many times when I increase power above the threshold, the threshold increases and the ICE does not turn on.  Similarly, many times when I decrease power the threshold falls as I decrease power.  Other times, when I am well within the threshold, the ICE suddenly turns on.  It is as if the car's display is not completely in sync with the real threshold.  The actual threshold must be computed in the PCM or some other module and the car's display is probably estimating the value of that threshold based on the information it receives.  I wouldn't put much weight on the behavior of the ICE threshold shown by the car's display. 

The threshold also will increase up and down for me. When driving on the highway in EV Later I try to keep my foot on the gas on downhill stretches so that the ICE stays on. Thanks to Larry we know that this is more efficient than allowing the ICE to turn off, drain the 0.5 kWh of available energy in EV Later and then use the ICE to charge it back up. Keeping the ICE on usually requires keeping the power demand on the Empower screen just above the first tick mark at 65 MPH. As I go down a hill and my speed increases the threshold bar decreases. This allows me to release pressure from the pedal without the car going into EV mode. Sometimes I'll be driving along keeping the power demand just above the blue box when all of a sudden the blue box jumps up and turns off the ICE. I believe that this happens when the car decides that it has charged the HVB enough (since in this scenario the ICE is sending minimal power to the wheels and almost all its power to the HVB since I'm going downhill). I hate when this happens and it often leads me to gain more speed going down hills than I would like. When I drive I-35 from Minneapolis to Owatonna I set the cruise control at 65 because then I know I'll be okay speeding up to 70-75 on the rolling hills since the speed limit is 70 MPH.

[Rexracer]

*deleted, off topic at this point in the thread*

Edited November 10, 2014 at 04:36 PM by Rexracer

[openair]

In this thread we have the two theories.

 

One: that ev later will deplete the hybrid battery during ev later use based on visual observation of a more or less gradual drop of the ice threshold when the ev range is depleted.

 

And two: the distinction of hybrid and ev battery operation is software only based on the current true state of charge.

 

One is based on visual observation and opinion. With no quantification of the variables involved (time difference, power demands, other driving conditions).

 

Two is based on evidence drawn with OBD II scans of data from the battery.

 

I think rbort, that it is time to re-evaluate your assumption your previous experience with a more or less gradual decrease in the ice threshold is related to ev later use and consider some of the numerous other variables. At least until you can provide some quantified evidence of your own and before continuing to tell multiple other people there is something wrong with their vehicles.

[murphy]

When EV later is selected 95% of the battery is "locked in" according to the message on the screen.  I first observed what happens next on a two stage trip.  Half way through the trip I stopped for a break.  When I was ready to resume my trip I had to again select EV Later, since it doesn't stay selected.  Again it locked in 95% of what was left.  As you keep doing this, less and less of the HVB remains.  My original intention was to arrive at my destination with a full battery to use there.  That didn't happen.

[larryh]

When driving on the highway in EV Later I try to keep my foot on the gas on downhill stretches so that the IC stays on.

 

I let the ICE turn off going down hills.  It doesn't take much energy to propel the car going down hill.  As soon as the energy required on the Empower screen starts to rise towards one bar, I force the ICE to turn back on by pressing the accelerator.  The ICE will not have to work hard to recharge the HVB since not much energy was consumed while in EV mode going down the hill.

Edited November 10, 2014 at 08:51 PM by larryh

[stevedebi]

I appreciate all the folks providing information.

 

Could someone please post the exact specifications from Ford as to the HVB portion of the battery being different between the Fusion and the C-Max Energi? Would you then say that the C-Max (normal, not Energi) also only uses .5 KW in the hybrid mode? That seems low. I've seen some folks speak of specifications, but they did not provide them. Please do!

 

Also, for larry, I'm shocked that Ford would allow the LiIon battery to charge that high or that low. Are you sure the computer isn't just reporting a sub percentage of the actual battery capacity? After all, that OBDIII output can be whatever Ford desires.

 

I see nothing from the displays that would indicate that in EV Later the HVB is charging any more than whatever portion has been designated as the "normal" (charge sustaining) hybrid mode, whatever the KWh may be. There is probably some "wiggle" room in the algorithm to allow for various battery temperature variables and etc. I've seen raja post that it is -5% - +2%, but no source for that information.

 

Of course, there is no separate "hybrid" battery - there is only one battery back there. I've just been speaking of a reserved percentage for the charge sustaining mode.

[stevedebi]

Steve,

 

You should drive in auto all the time while driving ev. I used to switch it to ev only but don't do it any more. Auto allows the empower screen to show the engine threshold, ev now doesn't.

 

..

 

-=^Raja. (sent from Chilis, my car is at 69% now)

Raja,

I don't go to Auto while in EV unless I feel the conditions are right for capturing more energy, because in Auto mode, the EV will draw additional energy FROM the HVB if the system is in an energy "negative" mode, i.e., the hybrid portion of the battery is not charged up. I don't want it taking capacity out of the reserve.

 

Unless I'm misreading what you say? I don't use EV Now on the highway - just EV Later and Auto. Maybe that is what you meant.

[larryh]

Also, for larry, I'm shocked that Ford would allow the LiIon battery to charge that high or that low. Are you sure the computer isn't just reporting a sub percentage of the actual battery capacity? After all, that OBDIII output can be whatever Ford desires.

 

100% SOC corresponds to 7.2 kWh of energy in the HVB  The capacity of the HVB is 7.6 kWh.  The car does not charge the HVB to its full capacity.  It normally does not even charge it to 7.2 kWh.  Also, the car does not normally allow you to discharge the HVB to 14.5% SOC.  The ICE usually comes on much sooner.  You have to be very gentle with the accelerator to achieve that low a SOC. 

Edited November 10, 2014 at 09:49 PM by larryh

[larryh]

The following plot shows the SOC of the HVB during a recent trip.  The blue line is the actual SOC, which can only be read using an OBD II scanner.  The red line is the displayed SOC.  This is what is shown on MFT (when not in hybrid mode) or on the 2D HVB icon on the display (when in hybrid mode).  The green line indicates the EV mode:

 

10 - EV Auto

20 - Hybrid Mode

30 - EV Later

40 - EV Now

 

Each time I switch to EV later (30), you can see the SOC of the HVB rise by a percent or two before leveling off as a result of the ICE charging the HVB.  After initially charging the HVB, EV later mode holds the SOC of the HVB fairly constant.  When the actual SOC reaches 21.5% (displayed SOC reaches 0%), the car enters hybrid mode.  The red displayed SOC line now indicates the SOC on the 2D HVB icon.  It initially starts out at 100%.  In this case, it was down to 54% when I turned off the car.  You can see some spikes in the red curve during hybrid mode when the ICE came on to charge the HVB (there were no stops in this portion of the route except at the end). 

 

Edited November 10, 2014 at 10:18 PM by larryh

[larryh]

I appreciate all the folks providing information.

 

Could someone please post the exact specifications from Ford as to the HVB portion of the battery being different between the Fusion and the C-Max Energi? Would you then say that the C-Max (normal, not Energi) also only uses .5 KW in the hybrid mode? That seems low. I've seen some folks speak of specifications, but they did not provide them. Please do!

The capacity of the Hybrid's HVB is 1.4 kWh.  I think the range of SOC for varies between about 33% and 66%, so only about 1/3 of the capacity is used, or about 0.5 kWh.  This is the same as the Energi when it is in Hybrid Mode. 

Edited November 10, 2014 at 10:25 PM by larryh

[stevedebi]

Larry, OK I get the high SOC - 80% is what most LiIon batteries use for the "longevity", but they don't usually go below 40% on the low side. That Ford would allow in the 20's is surprising. I know Ford did a lot of studying based on the FEH when they made the C-Max and Fusion hybrids, and that they think they can have the batteries last. But that low seems pretty low!

 

Your numbers on the normal hybrid - 33 to 66% - match what the FEH did. This is what makes the Energi numbers so surprising.

 

I'll adjust my posts from now on to use the .5 number. It makes sense.

[rbort]

Steve...who said that? Liion battery range is from 20% to 100%. For long life don't drain below 20% and don't leave fully charged at 100% for more than several hours. For storage charge to 60% and keep cool.

 

-=^Raja.