How to prolong life and charging capacity of HVB in Ford Fusion Energi

[jshaevitz]

I purchased a 2013 Ford Fusion Energi 15 months ago with 23,000 miles on it.  There are now 36,000 miles on the car.  Battery capacity at full charge was 20-21 miles for the first year, but has gone down to 14-15 miles in the last few months.  I live in Central California with a mild climate - winter low temps in 30's overnight, summer highs average high 70's to low 80's with occasional 90-100 days.  I understand that battery capacity can be affected by driving habits, use of AC/heater, etc, but I feel that those issues are not the cause in my case.  I have read several of the threads dealing with the HVB degradation issues and am wondering if that is the cause.

 

A bit of detail about my usage.  I work from home and take several short (under 10mile) trips per day.  I plug in after each trip and unplug when I go on the next trip.  Usually the battery is not fully discharged at the end of each trip and usually the battery does get to 100% charge for each subsequent trip.  I use a 240v charger.

 

I have a few questions that I hope someone can help me with.

 

1.  Should the HVB be fully discharged before charging again?

2.  Should the plug be removed once charged to 100%?

3.  Should the HVB only be charged to about 85% capacity at each charging, rather than 100%?

4.  If the decrease in the battery capacity that I am experiencing is due to normal battery degradation, is there anything the dealer will be able to do to increase the capacity?

5.  Should I expect that the degradation should level off and stay relatively the same for the remainder of the life of the battery?

6.  How many miles do these batteries typically last?

7.  Any suggestions on how to increase battery capacity and prolong the battery life?

 

Thank you!

JS

[murphy]

1. No, that only applied to Ni-Cd batteries.  Li-Ion does not have a memory.

2. No, when the HVB reaches 100% it then starts charging the 12 volt battery if it needs it.

3. If that was required Ford would have given us a way to automatically stop at a lower SOC level.  It is my belief that when charged to 100% the battery is no where near its actual full capacity.

4. Are you using cabin heat?  A cold battery (anything below about 65° F is a cold battery) is less efficient.  Use of cabin heat will significantly reduce the range.  Mine drops to 10 miles when it is cold.

5. Don't know, the oldest battery is approaching 4 years old.

6. The battery is supposed to last for the life of the car.

7. Wait for warm weather, 24 hours a day.
 

[jshaevitz]

Thank you for your replies.

 

For item #4, I know that cabin heat/air affect the range but I am wondering about the overall drop in range from 20 miles max to 15 miles max.  We tried not using cabin heat for 2 1/2 weeks and there was no change in the range...it remains at 15 miles.  Is there any way for me to get the battery range back up to the original 20 miles?  Is there anything the dealer can do to affect that change?

[murphy]

What does MFM say is the kWh used for a trip that drains the battery from 100% to 0% with no engine usage?

 

It is not possible that turning off the cabin heat had no effect.  The cabin heater is a resistance heater that is rated at 5 kW.  When turned on it puts a huge load on the battery.  Put the climate gauge on the left display and verify that the climate bar does not move at all when the heat is turned off.   I'm now thinking that the heater isn't turning off.

[rbort]

1.  No, that's no necessary, however, might be more prudent to discharge it more, see other answers.

2.  Yes, you don't need it plugged in all the time, however, do not charge it to 100% all the time if you don't need it.  Spending time at 100% reduces battery life, spending time at a lower charge level increases battery life.  The lower the average charge level, the better.

3. Absolutely.  Only charge it to 100% if you think you need all of 100%.  If you don't then try not to.  So you go in and out a couple of times.  Maybe you charge it to 100%, then you use it in the morning, don't recharge back to 100, use it again, and then now its a lower charge level and you've used more of the charge and less cycling back to 100%.  Let say after the first use you see you have 35% left.  And you know you need to go for another trip but need about 60% battery, then charge it to 70%, go on that trip, and come home with 0 to 10% charge.  Wait as long as possible before recharging, better to charge early morning like 5am instead of right away when you get home from the 2nd trip at 7pm.  Again, less time dwelling at 100% charge level.  You can program value charge to charge later or you can plug it in when you wake up in the morning, whatever works for you.

4. I don't think so, damage is irreversible.  Its also additive, so a little bit of damage here and there adds up to something noticeable.  Try to not use the battery alot, especially during hotter weather, and charging and discharging it raises the battery temperature, and spending time with elevated temperatures damages the battery slowly but surely.  Also try to spend an hour to drain the battery, not 10 minutes at 70 mph on the freeway.  Use city street, go 30 to 40mph.  Less strain on the battery and less temperature rise.

5. Not particularly, its going to continue but you can expect to accelerate degradation if you do the wrong things or slow it down it you don't.  Things that degrade the battery, 1. time (can't help that), always ticking always degrading.  2. charge level, the lower the average level, the slower the degradation.  100% is worse than 80 worse than 60% worse than 20% etc.  If you don't intend to use the car the next day, then don't be afraid to leave it sitting at 10% charge level after you used it that day.  Better than recharging it to 100% and letting it sit for 2 days at 100%.  Only exception is don't let it sit empty in hybrid range.  If drain it all the way, the recharge it right away when you get home to somewhere around 5% and disconnect charger to let it cool down first. 3. Number of cycles, they are finite, don't expect unlimited cycles.  Better in my opinion to combine 2 to 3 trips per charge, so 100, to 68, to 44, to 21 and then recharge rather than 100 to 68 to 100 to 72 to 100 to 77%.  4. And most importantly, heat.  Using the battery more often during the hot weather and alot of in and out trips with recharging back to 100% with L2 is worse than using it less often and recharging with L1.  L1 doesn't give you that luxury of going in and out several times a day and hence in an indirect way helps you to keep the battery temperature down.  Having L2 at home in my opinion backfires and kills batteries faster, especially for the smaller pack that we have (7.6kwh)  The more elevated it becomes, the more the damage.  On hot days you may not want to recharge the battery more than once and wait until the early morning hours before recharging it again.

6. I have 63+k miles on my Cmax with about 36k of which are battery miles.  My battery is still OK, degraded from new for sure, but still can yield about 5.4kwh per charge.  When it was new I remember getting 5.9kwh out of a charge.  But its 3 2/3rd years old now too so I can't expect it to be 100% of original.

7. Read all above, should help plenty!

 

Right now my car sits at 29% charge.  It was at 50% charge earlier today and I had to go out to the grocery store and back this afternoon.  Its not plugged in as I don't have any plans for it for tomorrow at the moment.  Don't feel like you have to plug it back in as soon as you get back home.

 

-=>Raja.

Edited January 31, 2017 at 01:50 AM by rbort

[jshaevitz]

Thank you for taking time to respond with such well thought out answers to my questions....much appreciated!

[calidude]

What a great post! A lot of useful information. I'm new to EV's and this helped a lot!!!

[skyagade]

I'm of understanding that hard acceleration and higher speeds (i.e., higher discharge rates) affect battery's long-term health; does that mean the high(er) temperatures related to those two driving habits are responsible for degrading battery life? If so, then logically wouldn't higher charging rates (i.e., 240v vs. 120v) either of which also create high battery temperatures, also affect long-term battery health? Thus, would charging at 120v be better (for long-term battery health) than 240v (aside from other factors)...if the option is viable for the situation?

[jsamp]

I'm of understanding that hard acceleration and higher speeds (i.e., higher discharge rates) affect battery's long-term health; does that mean the high(er) temperatures related to those two driving habits are responsible for degrading battery life? If so, then logically wouldn't higher charging rates (i.e., 240v vs. 120v) either of which also create high battery temperatures, also affect long-term battery health? Thus, would charging at 120v be better (for long-term battery health) than 240v (aside from other factors)...if the option is viable for the situation?

 

Skyagade,  Right on all fronts.  Higher temps are a battery killer, especially when charging.  Keeping at 100% charge all the time is a killer.  Higher charging and discharging rates are a killer (freeway speeds on EV is bad).  Higher number of charges is a killer.  Driving EV with heat or A/C on is a killer (double demand on HV battery).  Basically using the car the way you had hoped is going to reduce battery life.

 

What can you do?  Only use EV at 50mph or less,  Accelerate gently,  Charge at 110V if possible.  Use heat and A/C sparingly and not while driving EV at higher speeds.  Basically anything to keep from high battery drain.

 

When in Hybrid mode, heat and A/C is not an issue as the HV battery isn't doing double duty, and the gas engine is also generating electricity.

[jj2me]

Driving EV with heat or A/C on is a killer (double demand on HV battery).

This summer I have been purposefully using the A/C when in EV mode, thinking the cooler cabin air is beneficial to cooling the HVB. Am I wrong?

[rbort]

Yes it depends.  While its nice for the battery to cool the air around it, the AC puts a load on the battery which raises its temperature.  I believe that the ambient temperature around the battery being cooler is less efficient than the battery itself heating up more from AC demand.

 

I would say run the AC for yourself if you need it. if you can open a window and live without it then go for that instead.  Also if you are home and its hot outside and you know you need the AC, plug in the car, turn it on, cool the car down so the initial high power demand for the AC comes mostly from the wall power, and then once the car is cooled off, disconnect the charger and drive off.

 

If you don't need to go out during the heat of the say, skip the 2nd paragraph all together and wait until the evening before going out on town on EV power.  At that time you can probably open all the windows and drive in somewhat cooler temps without the need for AC and without having your car bake in the hot sun as you run into the store.  (bad).

 

-=>Raja.

Edited August 20, 2019 at 11:33 PM by rbort

[jsamp]

Not only does this action potentially increase the battery temperature (bad) but it also greatly increases the drain rate on the battery (also bad as this can reduce battery life).  Raja has the best suggestion (no A/C if possible) or you can switch to gas to cool the cabin quickly then turn off A/C to run on electric.

Kinda sucks that we have to do this as it is a compromise to the ideal car.

[My14Energi]

Who the hell buys a car, fairly expensive car, and then doesnt use the a/c? Dumbest thing i have heard. All this car is is an enhanced hybrid. Forgot all this charging and battery crap, whats your mpg? Thats all that matters.....mpg. My lifetime avg is 43.2 mpg right now. Thats blasting a/c every single day, every second i am in the car....43.2. Thats the number thats important.

Edited September 10, 2017 at 01:10 PM by My14Energi

[Russael]

If you want to run your A/C (and I do), I always use recirculate.  Why?  Then it doesn't have to work nearly as hard to keep the cabin comfortable.  It doesn't have to try to cool outside air to your set temperature.  It can be 95 degrees outside and after maybe 5 minutes, the cabin is comfortable and then the A/C idles around maybe 500 watts.  500 watts is minuscule in the long run.  If you're so worried about the initial high drain, run the ICE until it catches up, and then switch back.  Or run it while plugged in (in to 240) with go times or remote start.  It usually only costs me a couple miles in range.

 

However, if the temp outside is comfortable to me, I don't run climate.

 

And I do run the heat in the winter.  I went 1 winter without it and I won't be doing that again.

[Timewellspent]

Who the hell buys a car, fairly expensive car, and then doesnt use the a/c? Dumbest thing i have heard. All this car is is an enhanced hybrid. Forgot all this charging and battery crap, whats your mpg? Thats all that matters.....mpg. My lifetime avg is 43.2 mpg right now. Thats blasting a/c every single day, every second i am in the car....43.2. Thats the number thats important.

 

My Lifetime according to the car is 108.9 mpg and 107.4 mpg per Fuelly and that is using the AC when it is really hot, and having the windows open when it's not.  It will drop like a rock come winter when I use the heat, but it will climb back once we get past winter and heat is no longer needed.

[jsamp]

Here is a great video on recommendations for preserving Li-Ion battery life (Tesla related, but applies to all):

 

http://insideevs.com/tesla-battery-experts-recommendation-maximum-battery-life/

 

Summary: only charge to what you need, preferably less than 70% of capacity.  50-70 seems to be the sweet spot.  If you need more it's okay, just don't leave it at max charge for an extended period of time.

[jsamp]

Who the hell buys a car, fairly expensive car, and then doesnt use the a/c? Dumbest thing i have heard. All this car is is an enhanced hybrid. Forgot all this charging and battery crap, whats your mpg? Thats all that matters.....mpg. My lifetime avg is 43.2 mpg right now. Thats blasting a/c every single day, every second i am in the car....43.2. Thats the number thats important.

 

My14, if you only care about MPG and 43.2 is fine with you, why did you spend the extra on an Energi when a Fusion Hybrid will do that?  My first trip in my Energi (bought used) was with an empty battery on hybrid mode only and I got 43.5MPG over 400 miles with some A/C use. 

[My14Energi]

Didnt pay extra, and my Energi is better equipped than any hybrid model i have seen. It was a showroom car that i got a great deal on. Btw, im down to 43.2 due to the summer heat. Winter time it goes up to 48 mpg. I get 63 mpg on my daily work commute, but dont charge during the day that often. Still no excuse for not running the a/c. And no, if i drove the same with only the hybrid i wouldnt be getting 43 mpg, would be far less

Edited September 13, 2017 at 05:48 AM by My14Energi

[ggonzalez]

Hello everyone, so I bought a 2017 Ford Energi three months ago, at first I was getting 21 EV miles at full charge, there was also a day that I got 29 EV miles, now at month 3 I'm getting 11-12 EV miles at full charge. This is what the display says before moving the car. I live in CA , so the weather is pretty much consistent. Should this be a battery warranty? 

[murphy]

Are you driving in EV Only mode at 85 mph?  High speed driving exhausts the battery in a hurry and severely impacts the electric range.  Anything over about 47 mph should be done in EV Later mode.  The air conditioner reduces mileage in EV Only mode.  The heater is worse but I doubt you need that in CA.

 

EV miles are an estimate based on previous usage of the battery.  When the temperature goes below freezing here I get about 10 miles before the HVB is empty.

 

You get 21 miles when the car is driven under the exact conditions of the EPA test of the car.

 

Battery capacity is not determined by miles.  It is determined by kWh.  How many kWh are recorded in your MFM account when the battery is charged from 0 to 100%?

[jj2me]

This summer I have been purposefully using the A/C when in EV mode, thinking the cooler cabin air is beneficial to cooling the HVB. Am I wrong?

 

 

Yes you are wrong.  While its nice for the battery to cool the air around it, the AC puts a load on the battery which raises its temperature.  I believe that the ambient temperature around the battery being cooler is less efficient than the battery itself heating up more from AC demand.

 

I would say run the AC for yourself if you need it. if you can open a window and live without it then go for that instead.  Also if you are home and its hot outside and you know you need the AC, plug in the car, turn it on, cool the car down so the initial high power demand for the AC comes mostly from the wall power, and then once the car is cooled off, disconnect the charger and drive off.

 

If you don't need to go out during the heat of the say, skip the 2nd paragraph all together and wait until the evening before going out on town on EV power.  At that time you can probably open all the windows and drive in somewhat cooler temps without the need for AC and without having your car bake in the hot sun as you run into the store.  (bad).

 

-=>Raja.

 

 

Not only does this action potentially increase the battery temperature (bad) but it also greatly increases the drain rate on the battery (also bad as this can reduce battery life).  Raja has the best suggestion (no A/C if possible) or you can switch to gas to cool the cabin quickly then turn off A/C to run on electric.

Kinda sucks that we have to do this as it is a compromise to the ideal car.

 

A little off topic for January, but according to this sae.org article about the Energi, use of A/C is stated as the assumed method to cool the battery in very hot weather:

 

"Ford has seen no durability problem with its battery pack from hot soak itself, Portalatin told AEI. So long as the vehicle is parked, peak temperatures in the battery compartment don’t affect battery capacity or longevity. Once the Energi is in use and the A/C is turned on (which can be assumed in very hot weather), pack temperatures quickly lower to an acceptable level."

 

Interesting also that the first sentence quoted above says there's no capacity or longevity problems of high SoC and high temps for a parked Energi. Presumably the problem comes when driving.

[EDIT: Note that the above quoted statement of "parked, peak temperatures ... don't affect battery longevity" contradicts page 18 of these National Renewable Energy Laboratory viewgraphs modeling battery behavior, which say: "Huge calendar lifetime benefit w/ delayed charging."

 

 

To optimize battery longevity, it sounds like perhaps we should be cooling off the Energi as soon as we turn it on.  Comfy that way, too.  Because "pack temperatures quickly lower ...", those who want to eek out as much EV driving from the battery as possible (as opposed to using charge for climate control) can soon thereafter turn off the A/C or set climate control to some high temp.

Edited January 16, 2018 at 08:47 PM by jj2me

[jsamp]

Interesting Ford says they've seen no durability problems.  But then I've not heard of these batteries dying completely, just losing capacity.

 

Personally, if it was really hot outside, I'd either run the A/C while plugged in as part of my go-time, or drive on ICE with the A/C on until the cabin was cool enough then switch to EV.  This is similar to what I do on cold days where I use the ICE to heat/defrost, then switch to EV.

[My14Energi]

I run my a/c everyday, all day for 10 months out of the year. Perhaps by doing so and not caring about squeezing every possible mile i've actually been helping promote battery longevity.

[bdginmo]

I run the AC when temperatures are above 80. When temperatures are above 90 I stop charging the HVB. This usually coincides with the summer billing rate when charging isn't as economically advantageous to me anyway. I'll let my HVB go months without charging. So far I have little if any degradation with 42,000 miles.

Edited January 19, 2018 at 01:55 AM by bdginmo

[jsamp]

I run my a/c everyday, all day for 10 months out of the year. Perhaps by doing so and not caring about squeezing every possible mile i've actually been helping promote battery longevity.

 

It's possible.  This is one of those gray areas.  High drain rate is bad, but so is heat.  So using the battery to run A/C to cool the battery may overcome the negative of higher drain rate.  The NREL report linked in that other thread lists Temperature as a key calendar life factor, and C-rate as a main cycle life factor.  It's possible you are reducing your cycle life  but increasing your calendar life, though I have a hard time understanding the difference between the two.

 

I guess we won't know for sure for many years if/when our batteries start dying.

Edited January 19, 2018 at 06:09 AM by jsamp