HVB and EV+ Mode: What is the relationship?

[agilix]

Hi everyone:

 

I have been driving a POC 2013 C-Max SE for about five months, and have put about 5000 miles on it (total 23000 miles now). I have a question about the HVB capacity and the battery status after daily drive.

 

I seem to read somewhere that EV+ mode would optimize the HVB for parking and storage. I also read that for long term storage and extended life of the HVB, it is not ideal to have the battery fully charged when not driving for a period of time. It is better at 50% level for the battery to last longer.

 

I think these designs all make sense: when I reach the frequent destination (like my home), the C-Max recognizes the location, and the EV+ mode kicks in. It looks like to increase the performance (usage and torque) of the HVB motor for the last quarter mile, so when I park in my garage, the HVB is not fully charged.

 

I recently noticed that the HVB level is quite low after park, such as barely 25% of the full level on the HVB bar on the panel. Also, when I start driving the next morning, the level appears to drop even lower, to certain degree that once in a while, the gas engine immediately kicks in when I start the car. Is that normal?

 

What is your HVB level when you park your car for the day? What is the optimal level for the HVB for longer life? Thanks!

[plus 3 golfer]

A lot of this has been discussed before.  In summary, the HVB has a nominal storage capacity of 1.4 kWh.  The operating capacity is limited to around 30% - 70% of the 1.4 kWh.  Ford studies (there's a key life graph) supports a very long life.  The bottom line is given this operating range, the battery should last (stay above 80% storage capacity IIRC) for a few 100k miles.

 

Yes, there are studies on LI-Ion batteries where somewhere around a 50% charge is ideal for storage.

 

The charge on my HVB varies by EV+ location from around 55+ SOC to 40-%.

Also, the displayed battery symbol does not represent the SOC of the battery, but the SOC based on operating range.

Edited August 17, 2016 by Plus 3 Golfer

[plus 3 golfer]

Here's the Key Life graph and the graph on HVB SOC vs Displayed SOC on the Battery Symbol.  So, your 25% displayed SOC is really 36 % SOC of the HVB.

 

h.

 

[livesmith]

Also note that EV+ is not about being good to your battery for storage at all.

 

EV+ just lets you drain the battery a bit lower than it normally would so that you might not have to start your ICE to make it the last little bit home.

[fbov]

Also note that EV+ is not about being good to your battery for storage at all.

 

EV+ just lets you drain the battery a bit lower than it normally would so that you might not have to start your ICE to make it the last little bit home.

I call BS. Got any credentials behind it, or are you just spreading uninformed personal opinion?

 

Li-ion battery technology may be new, but it's well known that high charge levels accelerate failure, and life after storage is extended if stored with less than half charge. 

 

Then look at the feature, which is the only one I know of, in this car, that crosses the engine/entertainment CPU barrier. (Absence of such a barrier gets you on 60 Minutes.) GPS is part of entertainment, so it's clear that Ford made a specific exception to data crossing the barrier. 

 

Then there's the sophistication... it's not just keeping track of where you turn the car off. It's tracking how far away you are, and HVB state of charge. Higher charge will activate EV+ sooner, at greater distance from your destination. That's not simple.

 

Now, ask why Ford would invest in a such a complex-but-useless feature... and perhaps you'll understand the true value of your post. 

 

The last bit is to ask why it's not a Prius feature? They don't use Li-ion batteries in hybrids. This ain't rocket science, if you just do a little digging. 

 

HAve fun,

Frank

[Smiling Jack]

Also note that EV+ is not about being good to your battery for storage at all.

 

EV+ just lets you drain the battery a bit lower than it normally would so that you might not have to start your ICE to make it the last little bit home.

 

Livesmith is correct about this.

[jackalopetx]

I call BS. Got any credentials behind it, or are you just spreading uninformed personal opinion?

 

Li-ion battery technology may be new, but it's well known that high charge levels accelerate failure, and life after storage is extended if stored with less than half charge. 

 

Then look at the feature, which is the only one I know of, in this car, that crosses the engine/entertainment CPU barrier. (Absence of such a barrier gets you on 60 Minutes.) GPS is part of entertainment, so it's clear that Ford made a specific exception to data crossing the barrier. 

 

Then there's the sophistication... it's not just keeping track of where you turn the car off. It's tracking how far away you are, and HVB state of charge. Higher charge will activate EV+ sooner, at greater distance from your destination. That's not simple.

 

Now, ask why Ford would invest in a such a complex-but-useless feature... and perhaps you'll understand the true value of your post. 

 

The last bit is to ask why it's not a Prius feature? They don't use Li-ion batteries in hybrids. This ain't rocket science, if you just do a little digging. 

 

HAve fun,

Frank

 

With EV+ enabled mine seems to go down to the low end of the scale when I drive home, which I believe is 40% charge. Is 40% better than 70% overnight? 

Edited August 18, 2016 by jackalopetx

[plus 3 golfer]

Livesmith is correct about this.

livesmith, on 17 Aug 2016 - 10:05 AM, said:

Also note that EV+ is not about being good to your battery for storage at all.

 

EV+ just lets you drain the battery a bit lower than it normally would so that you might not have to start your ICE to make it the last little bit home.

 

Please provide documentation that Ford's intent is to do that.  

 

ICE not running (or ICE running less at that time is an outcome) not the rationale for developing EV+.  Second, Ford would not implement the algorithm for EV+ if it harmed the HVB.  Lowering the SOC of the HVB and cycles is a benefit.  Because consumers want to see more EV use (Ford press releases), it made sense to Ford to implement the algorithm in EV+.

 

I posted the press releases from Ford before on EV+.  Ford has a patent on the EV+ algorithm.  Ford's intent is to demonstrate that Ford can use a predictive algorithm to control the powertrain using small amounts of data storage and GPS.  I see this as a way in future vehicles to increase the hybrid powertrain efficiency while driving by altering the use of EV and ICE knowing what's ahead.  By being able to identify and predict load requirement as we drive, the software can better optimize the storing and use of energy in the HVB.  Is it better to use ICE or the HVB to climb a hill - it likely depends on what's on the other side of the hill.  

 

 

With EV+ enabled mine seems to go down to the low end of the scale when I drive home, which I believe is 40% charge. Is 40% better than 70% overnight? 

There's no question that long term storage is better at 40 % than 70%.  But also, charging to 70% vs say charging to 50% will shorten the cycle life of Li-Ion batteries. The cycle life of Li-Ion batteries increase if the maximum charge level of the cell is lower.  So, if EV+ reduces potential higher SOC levels, cycle life will be increased.  For me, that might be 3 - 6 reduced higher SOC levels a day.  This makes a lot more sense than what Livesmith and Smiling Jack believe - that EV+ is used so ICE doesn't have to run.

 

Also, in normal driving it's not likely one will get to 70% SOC.  Generally, one needs to go down a longer steeper hill to get to 70%.  What I observe, is that SOC above around 57% occurs during long stretches of regenerative braking.

 

Also, the elevation change to your EV+ location and the SOC before reaching the initiation of EV+, can significantly affect SOC at the EV+ location.  

 

My SOC going to the YMCA (an EV+ location) is downhill for the last mile.  So my SOC is always 55 - 60% when I arrive at the Y and I'm generally in EV mode the entire last mile.   Going home, EV+ triggers over one mile (street-wise) from my home which is about 0.35 miles (the typical distance that EV+ triggers as the crow flies).  This last mile is about 100 feet uphill.  So, my SOC at home is generally below 40% and sometimes ICE comes on during the last 200 feet up my steep drive way.

 

Perhaps in future hybrids, the powertrain control algorithm will know that my last my mile to the Y is downhill and alter the use of ICE and HVB prior to that last mile to get my SOC down from the 55-60% to below 50%.  

Edited August 18, 2016 by Plus 3 Golfer

[ptjones]

I use E+  and it comes on going to work and home.  I have a ScanGaugeII so I can monitor HVB SOC, I usually keep it between 38-50% SOC and only see it higher when I'm going down hill.  Going uphill doesn't charge the HVB very fast and if you get above 50% SOC the HVB will help going uphill.  When I get home my SOC is usually 38-43% and at work around 47%, work is a hundred feet higher elevation and 7 mi.  In the morning at home I have seen the lowest SOC of 28% and highest of 80%, which happened after getting back from FWY trip and put MADMAX away at night with 57% SOC. BTY you can go pretty far with 80% HVB SOC if you keep it under 35 mph so the ICE doesn't start up in the morning. I attribute this from the HVB cooling off at night.  IIRC it seemed that 62% SOC = full for Smart Gauge. :)

 

Paul

[fbov]

This is a great site for battery information. This page specifically addresses longevity factors. 

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

 

Ford can control maximum charge level and depth of discharge, and they do what they can for reliability. Key Life Test results say they did a good job here.  

 

Ford has no control over he user. In fact, Ford "knows" we owners are idiots, they have decades of warranty data. So they design idiot-proof turbochargers that won't cook the oil when you shut them down hot. That EV+ is intellectual property value is a bonus; Ford put some really neat things into this car. It's too bad sales didn't greet the innovations.  

 

Have fun,

Frank

Edited August 18, 2016 by fbov

[plus 3 golfer]

.. IIRC it seemed that 62% SOC = full for Smart Gauge. :)

 

Paul

My recording of data shows 65% SOC = full on the battery symbol (see graph above).

[obob]

 POC 2013 C-Max SE 

 

What does POC stand for in your post ?

[ptjones]

My recording of data shows 65% SOC = full on the battery symbol (see graph above).

I wonder if that changes with age of the HVB. I know now my HVB fills up quicker now.

 

Paul

[plus 3 golfer]

I wonder if that changes with age of the HVB. I know now my HVB fills up quicker now.

 

Paul

I wonder also as IIRC you mentioned this in another thread.  So, maybe as the battery ages and the nominal storage capacity declines, Ford reduces the operating range in kWh but in displaying the data for the battery symbol still uses the 1.4 kWh initial nominal range.   For example, if the storage drops 5%, the top end of the nominal operating range drops 5% but the bottom of the range (in kWh) probably stays the same (don't want to drop below the knee of the curve).   So, the battery would fill quicker.  Also, then if the displayed battery symbol still used the 1.4 kWh in the conversion from actual SOC to the displayed, one would then see the battery symbol show full at a lower %.

 

IIRC, I had about 45 - 55 k miles on my car when I recorded the data and got the 65%.  hannahWCU logged the data below where SOC is the actual and SoC is the battery displayed.  I wonder how many miles hannahWCU had on his car when the data was observed around May 2013.

 

Note that hannahWCU data if plotted on my graph would be to the right of my data.  The slope he gets is about 38%.  It would be interesting to see how your car compares to hannahWCU's data as you have significantly more miles.

 

 When SoC reads 100 - SOC reads 69.7

When SoC reads 80 - SOC reads 62.1

When SoC reads 70 - SOC reads 58.0

When SoC reads 50 - SOC reads 50.4

When SoC reads 30 - SOC reads 42.7

Edited August 19, 2016 by Plus 3 Golfer

[jestevens]

If you are concerned about the reliability of your battery pack Ford warrants the hybrid system components for 8 years or 100,000mi in all states and 10 years/150,000mi in certain other states (but unfortunately not New York).  I would expect typical replacement cost to be around $4K, same as buying a new transmission for a similar non-hybrid auto.

[livesmith]

I call BS. Got any credentials behind it, or are you just spreading uninformed personal opinion?

 

Li-ion battery technology may be new, but it's well known that high charge levels accelerate failure, and life after storage is extended if stored with less than half charge. 

 

Then look at the feature, which is the only one I know of, in this car, that crosses the engine/entertainment CPU barrier. (Absence of such a barrier gets you on 60 Minutes.) GPS is part of entertainment, so it's clear that Ford made a specific exception to data crossing the barrier. 

 

Then there's the sophistication... it's not just keeping track of where you turn the car off. It's tracking how far away you are, and HVB state of charge. Higher charge will activate EV+ sooner, at greater distance from your destination. That's not simple.

 

Now, ask why Ford would invest in a such a complex-but-useless feature... and perhaps you'll understand the true value of your post. 

 

The last bit is to ask why it's not a Prius feature? They don't use Li-ion batteries in hybrids. This ain't rocket science, if you just do a little digging. 

 

HAve fun,

Frank

BS on what part?

 

Show me some information anywhere that EV+ is anything at all towards battery longevity...  I've certainly not seen it...

 

Here's a video from Ford which I believe is the same thing it says in the manual...

 

I quote:

"EV+ is a system that allows the customer to get more driving in EV mode as they approach a familiar destination."

He goes on to say "that if we knew the vehicle was going to key off in a mile, we'd try to turn the engine off more."

 

So...  which part do you think I've mis-represented, or is there that leads you to believe that this feature has anything to do with long term storage?

 

I'm not necessarily saying that it's bad for the battery, just that that's not it's purpose.  It simply loosens the limits on EV mode to allow you a better chance to keep the ICE off.  

I've got an Energi so my lower end is I think under 20%SOC if hybrid mode gets towards the bottom.  But, if it would normally only allow me one bar of EV power before kicking on the ICE, in EV+ mode it might allow me to use 2 bars of power.

 

It may or may not be better for storage long term, but if Ford normally deems the limits for using the battery are X, then why would it be better to allow you to draw more amperage for a longer time while the battery is at a lower SOC?  Again, not saying it's terribly detrimental, but I'm doubting there's any benefit to the battery from it.

 

All it does is say "You're X distance from these GPS coordinate where you key off the vehicle frequently. You now enter EV+ mode and we'll let you use more battery amps/lower SOC than normal."(not a huge amount more though).

So yes, I live halfway up a hill.  Usually I EV+ kicks on for me just as I hit the flat spot above the hill so I enter the garage with an almost full hybrid battery.  Now, if I come home from the other direction I can drive closer to normal and the uphill will kick in the ICE anyway and I'll be about midrange hybrid battery.  But if I really baby it and try to keep it in EV mode as much as possible and climb that hill at like 5mph, then I can get in there with about 20% showing on the hybrid portion of the battery.

 

 

I've not seen any report or first hand experience of a higher SOC activating EV+ sooner.  Only distance from a set of coordinates where you key off the vehicle.  If you've evidence otherwise, please provide.

 

Why would Ford invest in such a feature?  I dunno, same reason as any other little thing like Eco cruise.  I don't think it's quite as complicated as you make it out to be.  Sure there was time invested.  I recall somewhere reading that they were having trouble figuring out how to do it because it would require a lot of processing of GPS, map data, etc and then they realized they could just use coordinates and the code became quite small/easy to process.  But it's just another nice little feature.  From what I've seen Ford has more features, options, gadgets and gizmos than anyone else.  Why bother investing in the brake coach or leaves?  It furthers the "green" image they are trying to portray to get people to buy these cars.  

 

Toyota has something like leaves as well as I recall.  They just haven't chosen to implement such a feature.  Sure, Ford's got a patent on it but I imagine if they tried hard enough other manufacturers could do such a thing, it's just not something they've deemed important enough.  Though I also get the impression that Toyota is prioritizing emissions or engine life or something compared to Ford as from what little I've read and experienced it seems the Prius is a lot more likely to fire up the ICE as it seems to want to keep the cat at full temps or some such thing.  I think Toyota may use a slightly smaller percentage of the battery as well.

 

And Toyota does use some Li-Ion in Prius' it's just not the majority of them.

[livesmith]

If you are concerned about the reliability of your battery pack Ford warrants the hybrid system components for 8 years or 100,000mi in all states and 10 years/150,000mi in certain other states (but unfortunately not New York).  I would expect typical replacement cost to be around $4K, same as buying a new transmission for a similar non-hybrid auto.

Weird, I thought NY WAS in that list of extended states...

 

The thing is that for the most part, this is only going to be a factor if your battery up and dies completely.  If your battery capacity degrades to half you'll have a heck of a time trying to talk a dealer into that being warranty work that needs to be done.  For that matter on a hybrid you might not even notice much.  On an Energi it will be more evident but I think I've only seen a single mention somewhere of it only being a "failure" if the battery is down to around 60% capacity and even then I think I've only ever heard of a single dealer actually agreeing to it.  I've seen a number of reports of Energi owners who have seen a drop to maybe around 75% capacity.

[ptjones]

I believe the HVB will probably last as long as the car.  With 136K mi. I'm getting as good of MPG's as I ever have. I think I'm using only about 10% of the HVB (38 to 48%) most of the time.  IIRC I have seen a couple of times where actual SOC was less than 40% and the CMAX wouldn't  go into EV+ Mode, not sure why.  In EV+ I think I can get down to 32% SOC before ICE kicks in. When SOC gets below 34% the ICE jerks when starting. :)

 

Paul

[livesmith]

When SOC gets below 34% the ICE jerks when starting. :)

 

Paul

Interesting note...  I've frequently thought that the C-Max seems a bit less refined in it's ICE starting and stopping(most notably from a dead stop) compared to my old Prius.  But with my Energi most of the time I'd have the ICE running would be when my battery is closer to 20%...  I would have thought that there would be enough volt/amp regulation to keep the car performing the same no matter the normal battery levels, but now you've got me wondering if there is something that makes it less smooth when the battery voltage is lower...

[cwstnsko]

Keep in mind that 20% on an Energi Battery would be a much higher % in a hybrid battery in terms of energy available.

 

I haven't driven a Prius, but I have a hard time imagining it being much smoother transition than my 2015 C-Max Energi.  In my car, if I don't mention it, my passengers can't tell when the engine starts, or if it is running or not, unless I am accelerating up an on-ramp or something similar that brings the rpms up considerably.

 

From reading this thread, it appears that Energi drivers have a slightly different perception of the primary benefit of EV+ than Hybrid drivers do.  I think the Energi drivers focus on not starting the ICE is because they commonly drive for days or weeks without starting the ICE.  In an Energi, creeping into the driveway in EV+ with half of the Hybrid portion of the battery consumed, but without starting the ICE, creates a curious euphoria that I have never experienced in a hybrid, ICE car, or BEV.  It's like you just won a hard level on a video game :-)

[obob]

I believe the HVB will probably last as long as the car.  With 136K mi. I'm getting as good of MPG's as I ever have. I think I'm using only about 10% of the HVB (38 to 48%) most of the time.  IIRC I have seen a couple of times where actual SOC was less than 40% and the CMAX wouldn't  go into EV+ Mode, not sure why.  In EV+ I think I can get down to 32% SOC before ICE kicks in. When SOC gets below 34% the ICE jerks when starting. :)

 

Paul

 

There is a thread around here that describes four C-Maxes which where monitored to the max by some government agency.  As I recall, after about 100K miles there was around a 5% reduction in some HVB measurement.

 

I do believe leaving the battery overnight at a lower state of charge will increase longevity, it probably isn't going to be that big a deal.  (There is also a thread about the reasons for that.)

 

I also noticed on ebay C-Max hybrid HV Batteries for sale in the 500-600 range.  They don't seem to be wearing out as fast as spares are becoming available.  (Though people do buy used batteries to take apart)

Edited August 19, 2016 by obob

[ptjones]

Interesting note...  I've frequently thought that the C-Max seems a bit less refined in it's ICE starting and stopping(most notably from a dead stop) compared to my old Prius.  But with my Energi most of the time I'd have the ICE running would be when my battery is closer to 20%...  I would have thought that there would be enough volt/amp regulation to keep the car performing the same no matter the normal battery levels, but now you've got me wondering if there is something that makes it less smooth when the battery voltage is lower...

The HVB isn't suppose to be getting down to 32% or less, but happens when some kind of HVB check or test is done over night.  Starting a cold ICE with low Volts requires more amps, this doesn't happen when ICE is warmed up and HVB is charged up some.  Prius has half the size HVB ,even smaller DC Motors than the CMAX and runs the ICE most of time.  I have driven my Daughter's 2011 Prius a few times on trips and the ICE runs constantly vs the CMAX ICE runs 60% of the time.  My Life Time EV is 50%  and as far as I can tell Prius doesn't keep track of EV time and instead uses the EV to assist the ICE. As you can see the CMAX and Prius are two quite different Hybrids and IMO I like the CMAX much better. :)

 

Paul 

 

Paul

[jestevens]

Here is the warranty guide for the 2013 Hybrid..

 

http://www.ford.com/resources/ford/general/pdf/2013HybridWarranty.pdf

 

It says New York adopted the Emission Standards but not the California Emissions warranty.

 

It also says that non-functioning battery pack due to gradual loss over time or "improper storage" is not covered.  So basically if you have a sudden unexpected pack that won't hold a charge it's covered..?

 

Here's the other article I found..

 

http://cmaxchat.com/?p=766

 

The simple explanation I have is that EV+ uses your car's GPS (yes, it has a GPS) to figure out places where you park 11 or more times in a row.  When it senses you coming close to one of these places it allows more range on pure EV to draw the pack down, knowing that it is likely the next time you start the car up the engine will be "cold" and it can charge the pack up while it's going through an engine warm up cycle.  The battery is probably "happier"  at a lower state of charge while it is in a resting state  (but not discharged)

 

The first time I drove a C-MAX I couldn't get over the whiny engine noise either but that was pretty much because the battery was at a low SoC on a car that hadn't been driven in a while - normal use I find that my engine doesn't sound like it has a huge load at idle.  I was impressed with the performance of the car - it does use the battery more than the Prius does. 

 

I've had both vehicles and you can pretty much guarantee that at least for Gen II the Prius ICE kicks in around 40MPH because of the way the PSD is designed.  It's still a great sedan, but I love the C-MAX crossover a lot more than the Prius v wagon - I test drove the v wagon and it had -no- power - it was like someone just took the standard prius drivetrain and added 2,000lbs.

 

Prius also has a thermos where it can store warm coolant to jump start warming up the engine from a cold start and PTC electric heaters to supplement engine heat in the passenger compartment.  I think only the Energi has electric heater, the regular C-MAX hybrid for whatever reason only has engine heat available.

Edited August 19, 2016 by jestevens

[jestevens]

Ford Engineers chose to use Lithium Ion packs instead of the more traditional NiMH packs Toyota has been using, I guess they think they are going to be even more durable, therefore they can use the battery more aggressively.  Over on priuschat the toyota NiMH packs seem to be lasting a long time, about 10-15 years and at least 100,000mi ..  Of course the SoC range does go down over the life of the vehicle until they get the dreaded Triangle of Death.  Pay $1500 for a refurb or $4000 for a new pack, trade up..

 

Who knows how long the Li-on packs will last?  It's still a newer technology - maybe cab drivers in NYC?  I still like the car a lot better than most others on the road - it's a good value - the only thing I've ever really had the car in for is oil change, tires and module reprogramming (free)..

 

http://www.designnews.com/author.asp?doc_id=256425

Edited August 20, 2016 by jestevens

[ptjones]

Just filled up, 788mi. total, 530mi. EV 68% EV, 58MPG and 50% city. :shift:  You would be hard pressed to do that in a Prius, let alone a Prius V. :yahoo:

 

Paul