Energi has a (manual) charge mode while driving.

[jsamp]

Second after my primary complaint with the Energi (small trunk), the next biggest disappointment I have is that they did not put in a "charge mode" so that you can charge the battery while driving.  This would be really handy for long trips where you need more than 20ish miles of EV at both ends for city driving and the ICE for the freeway in between.

 

Most people know that on a long downhill you can gain charge and miles, but I've figured out a way to gain charge from the gas engine alone.

 

Despite what some have said on these forums, I've noticed on my Energi (2015 SE) that whenever I put it into EV-Later mode two things happen:

 

 - it displays "XX% battery saved" on the left screen, where XX matches what the center screen says.

 - it immediately starts charging the battery, adding ~2% over the next few miles.

 

So during a long Freeway trip today (65 MPH, 140 miles each way) I did an experiment.  I left with 79% charge and the display saying 19 miles.  Along the way, I would put it into EV Later mode, let it charge up the 2%, then get it to go into EV mode and quickly switch the selector through Auto > EV > EV Later to "lock in" the 2% increase.  Sometimes I could only get 1% but the end result was the same.  Over the course of 140 miles, I got it up to 94% charge and 27 miles on the display.

 

While at my destination I used most of the battery in town and began the return journey at 11% and 2 miles on the display.  Working it aggressively I was able to get it up to 51%  and 17 miles by the time I got home.  So apparently you CAN charge the battery while driving, if you work at it.  Over the 2-1/2 hour trip I added 40% to the battery, which is about the same as charging at 110V level 1.

 

For the naysayers, I specifically did NOT capture any charge gained by downhills, because that would not meet my criteria of all gain due to the engine charging the battery.  I could have gained 4-5% more if I had done that.  The best result was a ~8 mile stretch along a perfectly flat causeway, where I did it twice and was able to add 4% over that distance.

 

The icing on the cake? I was able to get over 46MPG while doing this.

 

Now, this is completely ridiculous to have to do this, when Ford could have easily put a charge mode in the Energi like Honda did with the Accord PHEV and Audi did with the A3 Sport E-Tron.

 

Disclaimer: I don't know if this works on all years, but it works on my 2015.  I assume the C-Max Energi can do the same thing.

[bdginmo]

Yep, I've used this trick before. It's not well known, but there are threads in which we've talked about the EV button cycle trick. It's easier to do if you have a ScanGauge because you can see the SoC to one decimal place. I think the consensus is that while it is useful in some scenarios it is probably not as efficient iin most cases. There are people on here that did some experiments and determined they'd end with better mpgs than if they had used this trick. However, I do agree that there should have been a manual charge mode. Afterall, I believe the manual says you're supposed to store your car at 60% SoC (or something like that) if doing so for long periods. If you don't have access to corded charging then this would be a great way to bring the SoC up.

Edited April 13, 2018 at 02:59 AM by bdginmo

[YoloSwaggins]

Electrical engineer speaking here:

 

you guys haven't stumbled across some sweet hack Ford doesn't want you to know about. all you're doing is wasting gas for no reason. 

 

First: Car companies spend hundreds of millions of dollars per year researching ways to squeeze 1 or 2 more MPG's out of a car so they can get a leg up on their competition. if there was a way for them to claim they could increase driving efficiency, i promise you, they would have already done so, because it would have saved them millions of dollars.

 

Second: it's MUCH more efficient burning gas to drive 20 miles, that it is for you to Burn gas to drive a generator to charge a battery to drive a motor to drive the car 20 miles. there is so much energy lost in that whole process and it all comes ultimately from your gas tank. The whole point of owning an EV is that its much cheaper driving on electricity from a power plant than it is from burning gas and this defeats the whole purpose of having a fully charged battery. its costing you ~$3 to charge you battery the way you're doing it vs ¢77 charging it from the wall.

 

Third: as for you getting "46 MPG:" the way the Energi calculates "MPG" when using electricity, is WAY different from actual miles per gallon when you're burning fuel. Rapidly switching between the two is causing a glitch that is tricking the car (and you) into thinking you're getting better MPG's than you really are. there are other glitches similar to this, such as resetting your MPG meter, running on gas for 20 seconds then switching over to EV for a while. within a few minutes your "Average MPG" will be like 999MPG which is impossible. 

 

Fourth: youre damaging your generator using it in a way its not meant to be used. normally it only has to deal with generating electricity for a short amount of time when you brake, but using it to charge the batter is causing too much heat to build up in the generator windings thus drastically reducing the life of your drive-train. 

Edited April 10, 2018 at 05:17 PM by murphy
Line with vulgarity deleted.

[jsamp]

Car companies do not know how my trip is going to go.  I do.  If I know I am going to have a bunch of miles of city driving at the end of my trip, when I can drive pure EV, the end result will be BETTER mpg overall.  That is when I employ this trick.

 

I check the mpg against my gas purchases. verifying the 46 MPG.  It is accurate.

 

It is not "damaging" the generator to use it for what it is designed for.  Ford programmed it to generate conservatively.  Going down hill generates electricity faster than the engine does, so it certainly CAN do more that what it does when I'm generating via the ICE.

Edited April 10, 2018 at 09:44 PM by jsamp

[YoloSwaggins]

That doesn't make any sense. Even if you had city driving left in your trip and you didn't have any EV mileage left, its still way more efficient to just do your city drive using gas, than it would be to use gas to generate battery power for you to use in the city. You're spending way more money on gas trying to generate electricity for no reason, than you are saving by driving in EV mode in the city. 

 

according to basic laws of physics, its physically impossible for this to get you a better overall MPG than just not doing it at all. You need to look into Energy conversion loss: https://en.wikipedia.org/wiki/Energy_conversion_efficiency

 

If you had city driving coming up in your trip, you should have saved battery power for it by switching to EV Later long before you ran out of Battery. 

 

regardless of whether the Generator can handle it or not, its not designed for what you're doing, and you're still putting unnecessary stress on it that not only isn't benefiting you, its counterproductive to your mileage efficiency. Not to mention, its degrading the life of your HV battery by charging it for no reason.

 

Its your car and you're free to do whatever you want with it, but you're naive to the features and functions of the car and you're spreading misinformation. You might convince other forum members who are new Energi drivers to waste money and unintentionally damage their drivetrain which is the only reason that I care. 

Edited April 10, 2018 at 07:02 PM by YoloSwaggins

[jsamp]

That doesn't make any sense. Even if you had city driving left in your trip and you didn't have any EV mileage left, its still way more efficient to just do your city drive using gas, than it would be to use gas to generate battery power for you to use in the city. You're spending way more money on gas trying to generate electricity for no reason, than you are saving by driving in EV mode in the city.

 

If what you say were to be true, then standard hybrids would not get better gas mileage than the equivalent ICE car.  Everybody on this site knows that is not true.  A hybrid gets better mileage because it uses electric propulsion when it is more efficient than a gas engine would be (mostly at lower speeds) even when that electricity came from the gas engine.

 

I was using the gas to charge the battery while driving at freeway speeds.  Yes, it slightly reduces the efficiency during that portion where it is charging, but only a minor amount (1-2mpg).  I then used that electricity to drive 25 miles around town using no gas, which was WAY more efficient than using the ICE.  Net result is better overall mileage. 

 

I WAS using EV later which is how I did this in the first place.  As I said in the original post I started the trip with 79%. So not only did I save that for the city driving, I added to it. 

 

Would it have been better and more efficient to use a wall plug for the electricity? Absolutely.  But I did not have the time to "top off" the battery before leaving, nor did I have access to a charger while at my destination.  So I used the engine to gain the electricity I needed for the low speed driving I knew I was going to be doing at my destination.  It is not worth doing all the time, but for trips like mine it was a good solution.  I am not promoting doing this all the time, every day.

[YoloSwaggins]

You're not getting what I'm saying at all. This has nothing to do with Hybrids being more fuel efficient. (which they are)

 

regardless, I don't know what you saw to make you think you were getting better overall MPG by abusing the EV Later button to "top off" your battery, but I promise you you weren't. Its not physically possible. I would send you a link to a page about the laws of conservation of energy, but I don't think you would understand any of it or why I'm linking it to you. 

 

This is a somewhat complicated and confusing topic, so I don't blame you for not understanding, especially since the Chevy Volt uses a gas generator to power the vehicles all electric drivetrain when the battery gets depleted, but even the Chevy Volt (which has a dedicated engine used for generating electricity) doesn't have a Charge Mode in which you can use the generator to top the battery off, because it would make no sense to do that.

 

There is not a single circumstance in which using this trick would help you in any way. Yes its charging your battery up, and yes using the electric motor is way more efficient than the ICE, but the fuel you burned in the process of charging the battery would have been more efficiently used to just drive the car, even in the city. Using the battery isn't more efficient than using the ICE if you used the ICE to charge the battery in the first place. That's why ford didn't make a "Charge Mode" (plus a bunch of other reasons).

Edited April 10, 2018 at 11:26 PM by YoloSwaggins

[murphy]

I'll spell it out. 

 

The engine turns one of the AC motor/generators to generate 3 phase electricity.  That 3 phase electricity has to be rectified to DC to charge the battery.  There is loss in that process.

 

For the car to run in electric mode DC from the battery is fed to an inverter which converts it to 3 phase AC.  There is also loss in that process.

 

Power delivered directly to the wheels from the engine is more efficient than the engine charging and discharging a battery to drive the wheels.  The PHEV only makes sense when the electricity comes from the wall or in my case from the PV solar panels on the roof of my house.

 

There is a reason this power system is computer controlled.  It is really complicated to maintain maximum efficiency.

[jj2me]

I think what is being proposed is that the operating characteristics of the ICE and EV have different efficiency curves, each operating most efficiently in differing conditions.  We're not talking simple closed systems (e.g., there's heat losses, transmission losses, flywheel and crankshaft inertia), so if we're going to apply textbook physics we'd need to introduce all the parameters and look at the resulting efficiency curves.

 

A typical ICE mpg might be 18 City, 26 Highway.  It's more efficient at highway speeds.  An EV is the opposite.  Charging a battery from an ICE running at highway speeds takes advantage of the inertia of the heavy rotating parts, so I suspect it does this charging relatively efficiently.  Seems plausible, and we have anecdotal evidence.

[jsamp]

You're not getting what I'm saying at all. This has nothing to do with Hybrids being more fuel efficient. (which they are)

 

regardless, I don't know what you saw to make you think you were getting better overall MPG by abusing the EV Later button to "top off" your battery, but I promise you you weren't. Its not physically possible. I would send you a link to a page about the laws of conservation of energy, but I don't think you would understand any of it or why I'm linking it to you.

 

Yes, I do understand what you are saying.  And you don't need to be condescending in your reply.  I am an engineer as well (mechanical), and took the same physics classes as you.

 

You don't need a bunch of complicated physics to understand this, nor a detailed analysis of charging losses.  Let's look at an example (with real numbers).  Let's propose my 140 mile trip included 120 miles of highway, and 20 miles of city.  Also assume that I started the trip with zero miles on the plug-in portion of the HV battery. 

 

If I did the entire trip on gas, (using EPA numbers for my 2015 energi) I would get 120 miles at 36 MPG and 20 miles at 40 MPG.  That would be a total of 3.83 gallons over 140 miles averaging 36.5 MPG.

 

If I did the trip the way I describe, and were able to "gain" 20 miles of charge over the 120 freeway miles, but it cost me 4MPG to do so (32 MPG net), I would use 3.75 gallons of gas for the 120 miles, and get the 20 miles free because the electricity was generated from that gas.  So my total 140 miles used 3.75 gallons which is 37.3 MPG. 

 

37.3 MPG is better than 36.5 MPG. 

 

The only thing in question is whether I can get 32MPG on the freeway while charging the battery.  I claim I've done it, you claim physics doesn't allow that.  As jj2me pointed out, we are talking about different efficiency curves under different conditions.  I'm taking advantage of the highway efficiency to gain charge then use that charge in the city where it is most efficient.

[YoloSwaggins]

I think all of us have invested a little too much time into this conversation.

 

If it helps you enjoy your driving experience then go for it, as long as other people don't fall for it.  

 

:2thumbs:

Edited April 11, 2018 at 01:17 PM by YoloSwaggins

[jeff_h]

I think all of us have invested a little too much time into this conversation.

 

If it helps you enjoy your driving experience then go for it, as long as other people don't fall for it.  

 

:2thumbs:

 

Same thing I thought since the beginning few posts of this thread, and it's not the first time that debate's been had over the years in other threads.... and won't be the last!

Edited April 11, 2018 at 10:49 PM by jeff_h

[jj2me]

I don't think this "add electric miles while driving" trick works in the 2017. I went from 18% to 16% to 15% to 12% to 10% in 5 successive cycles. Looking at the Power Flow app, when I cycled into EV-Later, it didn't start using the ICE, but often stayed in, or soon went into Electric power.

 

The 2017 doesn't show percentage of charge except when you turn the car off. It shows electric miles remaining on the right-hand economy displays (mine went from 5 all the way to 1 in my tests). The 2017 has an advertised electric range of 22 miles, more than any other model year, so I suspect it has different programming for these conditions (unless I did something wrong).

[muzicman61]

I think when you shut off the vehicle, you do see a percentage of charge remaining in the left display.  I know I've seen it but don't remember the exact circumstances.  I have never seen my EV range increase when driving.

[murphy]

I think when you shut off the vehicle, you do see a percentage of charge remaining in the left display.  I know I've seen it but don't remember the exact circumstances.  I have never seen my EV range increase when driving.

Drive down a really big hill in EV mode.  Back in 2013 or 2014 someone used regen to provide the braking coming down from the top of Pike's Peak and fully charged the battery.

[jsamp]

I think when you shut off the vehicle, you do see a percentage of charge remaining in the left display.  I know I've seen it but don't remember the exact circumstances.  I have never seen my EV range increase when driving.

 

On my 2015, the middle screen displays the current % charge in a certain mode.  It's on the screen that shows the charge times and go times.  You can watch it go down as you drive and/or up when you brake.

 

Just coming off the freeway from 65mph down to a stop adds about 2% to the battery.  Of course, that's less than the amount it took you to get up to 65 getting on the freeway, but at least you get some back.

 

There is a fairly large hill in my town that can get me from the middle of hybrid mode up to 1% charge.  I've never done it with a % charge already on the battery to see how many % it adds, but I'm guessing it's between 5 and 10%.  The most I've added is 3+ miles on one long downhill on I-5 in CA.

Edited June 6, 2018 at 05:46 AM by jsamp

[16vjohn]

Yes, I do understand what you are saying.  And you don't need to be condescending in your reply.  I am an engineer as well (mechanical), and took the same physics classes as you.

 

You don't need a bunch of complicated physics to understand this, nor a detailed analysis of charging losses.  Let's look at an example (with real numbers).  Let's propose my 140 mile trip included 120 miles of highway, and 20 miles of city.  Also assume that I started the trip with zero miles on the plug-in portion of the HV battery. 

 

If I did the entire trip on gas, (using EPA numbers for my 2015 energi) I would get 120 miles at 36 MPG and 20 miles at 40 MPG.  That would be a total of 3.83 gallons over 140 miles averaging 36.5 MPG.

 

If I did the trip the way I describe, and were able to "gain" 20 miles of charge over the 120 freeway miles, but it cost me 4MPG to do so (32 MPG net), I would use 3.75 gallons of gas for the 120 miles, and get the 20 miles free because the electricity was generated from that gas.  So my total 140 miles used 3.75 gallons which is 37.3 MPG. 

 

37.3 MPG is better than 36.5 MPG. 

 

The only thing in question is whether I can get 32MPG on the freeway while charging the battery.  I claim I've done it, you claim physics doesn't allow that.  As jj2me pointed out, we are talking about different efficiency curves under different conditions.  I'm taking advantage of the highway efficiency to gain charge then use that charge in the city where it is most efficient.

 

If you are a mechanical engineer, then you also took stats... which should be your first indicator that you don't have enough data to make that call. Work your vehicle your way for 3 or 4 tanks of fuel tracking your kw/h as well as gasoline, then do it the other way. I can tell you that Yolo and Murphy are more correct... when you change any energy, there is loss. Simply put, does your battery get warm when you charge it or discharge it? Is there a cooling fan on the HVB? Ok, that's resistive loss.... that energy had to come from somewhere. When you charge the battery with the engine, your atkinson cycle engine is ~32% efficient, meaning nearly 3/4 of the energy in the fuel tank was lost to heat. Then you use the remaining mechanical energy to charge the battery... which conservatively is only 80% efficient. When you put the energy in the battery to use, there is more loss... conservatively 15% loss. The energy in the fuel tank is better used to directly drive the wheels, not charge a battery. This is why the Volt is capable of directly coupling the gas engine to the drive wheels, because it avoids conversion loss.

 

I get it though... you think that on the highway the gas engine is more efficient than in the city. You're right... but it's not making up for the conservative ~25% loss in charge/discharge. If you're an engineer, then get your data and come back to us to prove the rest of the world wrong... at this point, the dead horse has been beat for years here and on other EV/hybrid forums.

 

Good luck.

Edited July 3, 2018 at 02:00 PM by 16vjohn

[rowekmr]

Interesting old thread. Kinda brought me back to my school days listening to Mech Eng arguing with the Elec Eng lol. I try understand both points and I must say I am curious to try for myself.

[JATR4]

OBSERVATION:  I read the above posts with great interest.  I think what may be missing is what a hybrid vehicle (HV) does to get better mileage than a corresponding ICE vehicle.  Hybrids have small batteries that must be recharged often.  My Ford Fusion hybrid would go approximately 1/4 mile before the ICE kicked in to propel the vehicle and charge the battery so that the sequence could be repeated.   The sequence repeated approximately every mile.  I got approximately 42 mpg on the Fusion Hybrid which is much better than an ICE Fusion.  The ICE Fusion engine is larger than the 4-cylinder Atkinson engine in the hybrid. The charging in the Fusion hybrid is controlled by the computer. 

 

Isn't what jsamp doing on the Energi similar to what Ford does via computer on the Fusion hybrid?  jsamp is charging the HVB battery manually. 

 

Can we agree that a hybrid  gets better mileage than a corresponding ICE vehicle?  The  explanation appears to be that charging the battery while driving may increase mileage.  Regen, inertia of flywheels, etc.

 

I think that jsamp may be correct but I doubt that it makes much difference in the actual mpg.  It is not something that I would do.

Edited December 26, 2019 at 07:47 PM by JATR4

[ColoradoStateEE1982]

Physics reasons that a hybrid gets better MPG than a non-hybrid be because:

1) ICE is much smaller and more efficient than a non-hybrid bigger ICE. Easy proof would be to use identical big engines in both cars.

2) Energy is recaptured into battery by generator braking , rather than losing the energy by friction and ICE braking.

 

YoloSwaggins  is right, charging the battery while driving cannot improve MPG by "laws of conservation of energy"

Energy is lost permanently converting mechanical energy to battery storage and back to mechanical energy.

[theterminator93]

Bit of a thread resurrection there. Anyway, your last statement isn't actually correct.

 

Charging the battery while driving CAN improve MPG and hybrids universally do this (watch your battery SoC on the dash as you drive in hybrid mode - it charges towards a certain setpoint even when you're not doing braking or coasting). Here's why.

 

Gasoline engines have variable BSFC - that's how much fuel is required to generate one horsepower for one hour. This depends on the RPM, load (volumetric efficiency) and power required. For example, our engine might produce (arbitrary figures) 25 kW at 2000 RPM and use 2 gallons per hour to do that. But it might also produce 30 kW at 2500 RPM and only use 2.3 gallons per hour to do that. We're using 15% more fuel to get 20% more power. The engine is more efficient at the higher RPM and power output. This is an off-the-cuff example using made-up numbers, but look up a BSFC chart for an Atkinson cycle engine and you'll see the area where the engine is most efficient.

 

Consider this scenario - you're cruising along and you need 25 kW of energy to maintain speed. You're drawing power from the HVB to maintain that speed. When the HVB charge gets too low, the engine turns on and then provides the power to drive the car. However, the computer is programmed to run at the most efficient engine speed possible for a given power demand (throttle position). At lower throttle positions and power requirements the engine will always be more efficient running at a slightly higher RPM and power production than what your power demands are, so the computer will "over power" the engine and have it run at a more efficient speed. So the computer runs the engine to make 30 kW; 25 kW powers the car then the extra 5 kW is diverted to the battery. This effectively means you're getting the fuel economy of the engine as it it was always running at the more efficient operating RPM.

 

It doesn't make sense to charge the HVB in the Energi on the go because for hybrids, a prolonged high charge rate from the engine would merely serve to cause severe heat generation and battery degradation well ahead of the HVB's expected service lifespan. Not to mention these batteries are designed for high cycle life, so charging/discharging 10-20% of the battery for the purposes of normal hybrid-electric operation is more than sufficient to improve gasoline range.

 

This is why "pulse and glide" yields immense improvements in MPG in hybrids vs. just maintaining a constant speed when the ICE always runs. Charge the battery during the pulse, then use up that extra energy produced by the engine at its most efficient BSFC during the glide.

 

Yes, converting ICE energy to electro-chemical (battery) energy and back isn't 100% efficient, but consider how efficient the ICE is in the first place - upwards of 2/3 the energy in gasoline is wasted as heat!

Edited January 5, 2022 at 03:29 AM by theterminator93