Battery not holding enough charge

[bchawla]

Hello,
Re: FFE - leased June 2013.
For the 1st year of operation, the battery was charging up to 72 to 80 miles range. However, for the past 3 to 4 months (summer 2014), I am getting a charge of 62 to 68 miles only. The dealer says that it is due to the way I drive. I am not sure about that.

I would appreciate your thoughts?

I live in S. Ca

Thanks

 

[jmueller065]

Yes its the way you drive. The miles to empty meter (the "Guess-O-Meter") does not show you what is in the battery (like 1kWh = X miles). It is merely an estimate based on your recent power consumption.

Have you been using the heater more? Driving on the freeway more?

As an exercise to see how variable it is: While driving down the road turn the heater on and off. Watch as the GOM changes drastically with the state of the heater.
More info:
http://jamiegeek.myevblog.com/2013/10/12/the-guess-o-meter/

Side note: I think we need a sticky about the Guess O Meter!

 

[WattsUp]

For the 1st year of operation, the battery was charging up to 72 to 80 miles range. However, for the past 3 to 4 months (summer 2014), I am getting a charge of 62 to 68 miles only. The dealer says that it is due to the way I drive. I am not sure about that.

What is your average Wh/mi? This will answer everything.

You can determine your average Wh/mi by resetting one of the trip meters and then driving for a decent while -- say 100 miles -- in your normal style. (Btw, the trip meter must also be set to enhanced mode so it will display the Wh/mi.) If your average is something like 300 Wh/mi, then your car's estimate of around 62 miles per charge would NOT be surprising at all.

The math is simple:

19 kWh usable battery capacity / 300 average Wh/mi = 63.3 miles estimated for full charge

Most likely your driving style, or use of use heat or A/C, has changed between your first year and this year, causing your average Wh/mi to increase. A higher average Wh/mi will mean a lower estimate on the Guess-O-Meter (see formula above).

To "fix" this, simply drive more slowly and/or use the climate controls less. Also, check your tire pressure! Soft tires are harder to "push" along the surface of the road, requiring more energy per mile. For the FFE, the Ford-recommended tire pressure is 38 PSI (higher than many other cars). Personally, I run mine even higher at 45 PSI and see about 10% more range.

 

[bchawla]

I thank both of the people who replied. I will try their suggestions. I have not been using the heater.

 

[unplugged]

Since this topic is already started, I thought I would go a bit deeper. I have noted my concern about my FFE a few times because my range has been slowly slipping away. I made up a lot of excuses like I was going too fast or that the temperature was too hot or cold. So I started taking notes (and photos) of my end range.

Some background first. When I leased the car in May 2013, I made sure that I would have enough range to get to my folks' home about 60 miles away. Given the EPA estimate, I figured I would have a good cushion. What I didn't realize was how much elevation gain plays a part in range. My first trip, I cruised about 68 mph and I was stunned to see that I only had about 12 miles remaining when I got to my folks's house. When I returned home, I had more than 30 miles remaining. Then I realized that their house has an elevation gain of around 2,000 feet. Bingo!

So as a year of ownership passed, I found my trips getting closer and closer to battery depletion. I started slowing down, but eventually I became a hazard when I had to go 60 mph on the 25 miles or so of a 70 mph speed limit. I switched to going over the mountain pass which was not only a few miles less, but had a slower speed. But I did notice that when there was no traffic and I sliced through the mountain pass, my range was getting short again. Since I was so close to battery depletion, several times in the last month I would ride around and see what my final kWh reading was when the battery depleted warning showed. "Stop Safely Now. Battery Depleted."

Consistently, my battery shows 17.2 to 17.4 kWh at depletion. This was for both going to their house via the mountain pass and my return trip "downhill" to my house via the freeway. Finally, last week, the day after I had the car checked out for the battery depletion complaint, I ran out of battery 2 miles from their house.

The dealer told me that I need to take it up with Ford corporate because unless there is a trouble code, there is nothing they can do about it. So I am off to tackle this issue with Ford. My primary point is that after a year and a half, the FFE shouldn't show a 10%+ decline in usable battery kWh. Further, it doesn't appear that this is anything near usual for the FFE given the responses in this forum. My FFE has about 17,500 miles on it. It just doesn't seem normal.

Any thoughts as to how I can convince Ford there is something wrong? I'm not going to be able to make it to my folks' house for much longer if this continues.

 

[sefs]

I had a similar experience. I was down to 17.9 kWh before about 1% battery. It ended up being battery capacity miscalculation. Here is the gold standard for checking capacity: Fully charge the battery. With the car in your garage, turn it on and reset the trip meter. Roll down the windows, and turn the HVAC on max defrost. Turn off the rear window heater. Let the battery go all the way till the contactor opens. This will take a couple hours. This will be when the Ready to Drive green car goes away, not just when it says stop safely now. In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

 

[hybridbear]

Somewhere I remember someone posting that the battery will rebalance the cells only when left parked & plugged in for 24 hours after a full charge. I think the Ford dealer tech from WI posted this in the battery replacement thread. I believe he also said that this is the first step from Ford Engineering for troubleshooting battery concerns. I believe the dealer can monitor the battery rebalance procedure and view the history when the car is hooked up to IDS. Has your dealer done this, unplugged?

Since this topic is already started, I thought I would go a bit deeper. I have noted my concern about my FFE a few times because my range has been slowly slipping away. I made up a lot of excuses like I was going too fast or that the temperature was too hot or cold. So I started taking notes (and photos) of my end range.

Some background first. When I leased the car in May 2013, I made sure that I would have enough range to get to my folks' home about 60 miles away. Given the EPA estimate, I figured I would have a good cushion. What I didn't realize was how much elevation gain plays a part in range. My first trip, I cruised about 68 mph and I was stunned to see that I only had about 12 miles remaining when I got to my folks's house. When I returned home, I had more than 30 miles remaining. Then I realized that their house has an elevation gain of around 2,000 feet. Bingo!

So as a year of ownership passed, I found my trips getting closer and closer to battery depletion. I started slowing down, but eventually I became a hazard when I had to go 60 mph on the 25 miles or so of a 70 mph speed limit. I switched to going over the mountain pass which was not only a few miles less, but had a slower speed. But I did notice that when there was no traffic and I sliced through the mountain pass, my range was getting short again. Since I was so close to battery depletion, several times in the last month I would ride around and see what my final kWh reading was when the battery depleted warning showed. "Stop Safely Now. Battery Depleted."

Consistently, my battery shows 17.2 to 17.4 kWh at depletion. This was for both going to their house via the mountain pass and my return trip "downhill" to my house via the freeway. Finally, last week, the day after I had the car checked out for the battery depletion complaint, I ran out of battery 2 miles from their house.

The dealer told me that I need to take it up with Ford corporate because unless there is a trouble code, there is nothing they can do about it. So I am off to tackle this issue with Ford. My primary point is that after a year and a half, the FFE shouldn't show a 10%+ decline in usable battery kWh. Further, it doesn't appear that this is anything near usual for the FFE given the responses in this forum. My FFE has about 17,500 miles on it. It just doesn't seem normal.

Any thoughts as to how I can convince Ford there is something wrong? I'm not going to be able to make it to my folks' house for much longer if this continues.

 

[jeffand]

Check list for causes of reduced driving range
Driving conditions: Elevation change over the trip, cold temperature, stop and go traffic.
Driving speed. The faster you go the less distance you will go.
Excessive cargo. The more you haul the more energy you will use.
Low tire pressure. This is an easy one to over look.

The colder the battery pack the less the storage capacity will have. The storage capacity of lithium battery pack does goes up with the temperature.

 

[michael]

I had a similar experience. I was down to 17.9 kWh before about 1% battery. It ended up being battery capacity miscalculation. Here is the gold standard for checking capacity: Fully charge the battery. With the car in your garage, turn it on and reset the trip meter. Roll down the windows, and turn the HVAC on max defrost. Turn off the rear window heater. Let the battery go all the way till the contactor opens. This will take a couple hours. This will be when the Ready to Drive green car goes away, not just when it says stop safely now. In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Your procedure is very good and is much, much better than anything involving driving. Your procedure applies approximately 6 kW constant load and should take about three hours. However, battery temperature is also a factor. if the battery temperature is anywhere between (I believe) 50 F (10C) and 98 F (37 C) the TMS will be inactive and let the battery temperature vary.

According to one NREL paper

http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/evs17paper2.pdf

one Lithium battery (not the same one as in the FFE, but this illustrates the point) varied from approximately 7.3 Ah to 6.2 Ah over that range, a 15 % reduction which is large compared to the kind of differences (18.5 kWh vs 17 kWh, for example, 9 %) that we are worrying about when discussing battery degradation. Furthermore the NREL paper showed a decrease in open circuit Voltage and an increase in resistance at the lower temperature (no surprise, we all know this) so the available energy is reduced even more than the reduction in Ah alone would indicate.

The point is simply that battery testing must be done is very precisely controlled conditions to be meaningful. Driving the car tells us very little, and even a controlled discharge is subject to variations based on temperature and perhaps other factors.

 

[WattsUp]

In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Very interesting... and what happened next for you? Did this procedure itself "recalibrate" things, or did you need to have work done?

 

[sefs]

In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Very interesting... and what happened next for you? Did this procedure itself "recalibrate" things, or did you need to have work done?

I did the battery re calibration through IDS, however, I did not attempt to retest. I would have to do it again to see if it had an effect or not. The test let me know I could have kept driving another couple miles after the battery depleted warning appeared (in my situation, not necessarily anyone else's).

 

[sefs]

I had a similar experience. I was down to 17.9 kWh before about 1% battery. It ended up being battery capacity miscalculation. Here is the gold standard for checking capacity: Fully charge the battery. With the car in your garage, turn it on and reset the trip meter. Roll down the windows, and turn the HVAC on max defrost. Turn off the rear window heater. Let the battery go all the way till the contactor opens. This will take a couple hours. This will be when the Ready to Drive green car goes away, not just when it says stop safely now. In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Your procedure is very good and is much, much better than anything involving driving. Your procedure applies approximately 6 kW constant load and should take about three hours. However, battery temperature is also a factor. if the battery temperature is anywhere between (I believe) 50 F (10C) and 98 F (37 C) the TMS will be inactive and let the battery temperature vary.

According to one NREL paper

http://www.nrel.gov/vehiclesandfuels/energystorage/pdfs/evs17paper2.pdf

one Lithium battery (not the same one as in the FFE, but this illustrates the point) varied from approximately 7.3 Ah to 6.2 Ah over that range, a 15 % reduction which is large compared to the kind of differences (18.5 kWh vs 17 kWh, for example, 9 %) that we are worrying about when discussing battery degradation. Furthermore the NREL paper showed a decrease in open circuit Voltage and an increase in resistance at the lower temperature (no surprise, we all know this) so the available energy is reduced even more than the reduction in Ah alone would indicate.

The point is simply that battery testing must be done is very precisely controlled conditions to be meaningful. Driving the car tells us very little, and even a controlled discharge is subject to variations based on temperature and perhaps other factors.

Michael,

My test was during the summer. The car was soaked at about 68F. If I did it now, I would have to let it soak in my heated garage at 70F for at least 24 hours.

 

[davideos]

Since this topic is already started, I thought I would go a bit deeper. I have noted my concern about my FFE a few times because my range has been slowly slipping away. I made up a lot of excuses like I was going too fast or that the temperature was too hot or cold. So I started taking notes (and photos) of my end range.

Some background first. When I leased the car in May 2013, I made sure that I would have enough range to get to my folks' home about 60 miles away. Given the EPA estimate, I figured I would have a good cushion. What I didn't realize was how much elevation gain plays a part in range. My first trip, I cruised about 68 mph and I was stunned to see that I only had about 12 miles remaining when I got to my folks's house. When I returned home, I had more than 30 miles remaining. Then I realized that their house has an elevation gain of around 2,000 feet. Bingo!

So as a year of ownership passed, I found my trips getting closer and closer to battery depletion. I started slowing down, but eventually I became a hazard when I had to go 60 mph on the 25 miles or so of a 70 mph speed limit. I switched to going over the mountain pass which was not only a few miles less, but had a slower speed. But I did notice that when there was no traffic and I sliced through the mountain pass, my range was getting short again. Since I was so close to battery depletion, several times in the last month I would ride around and see what my final kWh reading was when the battery depleted warning showed. "Stop Safely Now. Battery Depleted."

Consistently, my battery shows 17.2 to 17.4 kWh at depletion. This was for both going to their house via the mountain pass and my return trip "downhill" to my house via the freeway. Finally, last week, the day after I had the car checked out for the battery depletion complaint, I ran out of battery 2 miles from their house.

The dealer told me that I need to take it up with Ford corporate because unless there is a trouble code, there is nothing they can do about it. So I am off to tackle this issue with Ford. My primary point is that after a year and a half, the FFE shouldn't show a 10%+ decline in usable battery kWh. Further, it doesn't appear that this is anything near usual for the FFE given the responses in this forum. My FFE has about 17,500 miles on it. It just doesn't seem normal.

Any thoughts as to how I can convince Ford there is something wrong? I'm not going to be able to make it to my folks' house for much longer if this continues.

I'm in about the same boat as you. My battery is about 17.2 to 17.4 at depletion. But that's where my battery has been at for as long as I can remember. Although I'm in Southern California and the temperature was in the high 50's this morning, my range is notably less...by about 10%. I remember seeing this last winter and it did get better in the summer; so I think that temperature has an affect at a higher temperature than spoken of on this forum...at least in my case. I'm not too concerned with it yet as I don't travel very far to work; although I have 19,000 miles on my FFE over 2 years. However, I see how it can be an issue for you as your goals for range are larger. Do you recall what your excess range was last winter around this same time / temp?

I'm going to see if I can leave it plugged in over this holiday since I will be taking the ICE with the whole family to grandma's house...over the river and through the woods.

 

[michael]

My guess, and it's only a guess, is that Ford rates the battery at 98 F since that's normally where the TMS cuts in. And that would be at 98 battery internal temperature, not ambient.

Do you have a way to measure internal temp during your testing? My impression is that the battery heats very little during discharge compared to the amount it heats during charge. However I've never done that test with the car parked, only when driving so there may be other factors

Also....my battery usually shows between 18.9 and 18.0 kWh when fully charged, but I never get that much when driving. More in the 17 to 17.5 range.

I have seen the rapid fall in energy in the first few miles of driving that many other have reported. And in the case of normal driving, your reported energy used will be less than the energy that could be taken from the battery using a procedure like sefs described. My normal drive depletes the battery in perhaps 90 minutes so heating losses will certainly be greater than at the 3 hour rate. My normal driving involves perhaps 20% or more regeneration which causes a further discrepancy between initial energy and reported consumption.

I can tell you this: I know several people with Leafs that have deteriorated, and there is absolutely no question that the car has been impaired. Their question isn't whether the car will regain range in the summer but whether it will be further damaged by then, or even be usable by then considering their range needs.

 

[michael]

Michael,

My test was during the summer. The car was soaked at about 68F. If I did it now, I would have to let it soak in my heated garage at 70F for at least 24 hours.

In that particular paper, Ah capacity reduced to about 6.8 Ah at 20 C (68F). So if my guess about the standard being 98 F is correct, this alone is likely enough to be easily seen during your testing.

I have no idea how much it might have heated up during the discharge.

 

[unplugged]

Thank you everyone. These are all great posts and I'll try a more refined and usable test in my garage once I have an opportunity.

Of course, my major concern is making this 60 mile run on a consistent basis. There are many variables that factor in to my drive, but I will try to isolate a few and report further information as it comes in.

As to what the dealer did; it wasn't much of anything. The dealer checked for trouble codes and recall/service bulletins. No testing was done.

 

[WattsUp]

In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Very interesting... and what happened next for you? Did this procedure itself "recalibrate" things, or did you need to have work done?

I did the battery re calibration through IDS ...

Even more curious, what does that mean?

 

[EVA]

I had a similar experience. I was down to 17.9 kWh before about 1% battery. It ended up being battery capacity miscalculation. Here is the gold standard for checking capacity: Fully charge the battery. With the car in your garage, turn it on and reset the trip meter. Roll down the windows, and turn the HVAC on max defrost. Turn off the rear window heater. Let the battery go all the way till the contactor opens. This will take a couple hours. This will be when the Ready to Drive green car goes away, not just when it says stop safely now. In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Sefs - What a great post. Thank you for finding a way to create a load without driving.

I'm trying to settle this in my head a bit, thinking through what's going on.

This test has to be pretty hard on the battery - you're taking the batteries down to zero charge, or really low charge. That can't be good for the batteries. Not a big deal to do this a few times, but a guy wouldn't want to do this a lot. Did I get that right?

If you think temperature is important, then doing this right after a full charge would be really important. That's when the batteries will be warmed up or cooled down from charging. They will be a consistent temperature. That pack is pretty darn dense, especially inside the car. I'm not sure 24 hours in a garage is going to get everything to the temperature you think.

I'm just thinking initial battery temperature should be monumentally irrelevant (for this test). The TMS will warm or cool the battery to whatever temperature it thinks is correct or best for the battery. The energy used to get there will be counted in the final reading at the end of the test. You don't care if the energy was used to run the HVAC, run the radio, or cool / heat the battery. You're just looking for a really fast heavy energy use to run the battery down in a reasonable amount of time.

Guess the temperature issue just goes away - if the battery starts out at 30 degrees, the car is going to warm up the battery to something higher, like maybe 50 or 60 degrees. If the battery gets warm, the car will cool it off. All that energy will be counted in the total used, right along with the energy to run the defroster.

So you start out with a fact - this test tells you the battery has this many kWh available. If it is only 16 kWh - then there is a problem with the battery. If it is near 20 - then the battery is fine.

How those kWhs translate to miles on the road is a totally different discussion.

 

[WattsUp]

This test has to be pretty hard on the battery - you're taking the batteries down to zero charge, or really low charge. That can't be good for the batteries. Not a big deal to do this a few times, but a guy wouldn't want to do this a lot. Did I get that right?

The car won't discharge the battery below about 10% (of the actual stored charge). So, no real danger in this test.

I'm just thinking initial battery temperature should be monumentally irrelevant (for this test).

That might be true if we can make the assumption that the TMS is actually capable of maintaining the optimal battery temperature at all times under all circumstances, or even tries to.

Personally, I would make the opposite assumption. That is, in extreme conditions, we should assume that the TMS might only "strive" to maintain the optimal temperature, but may not actually be able to completely do so. In such cases, the performance of the battery will be affected, including the apparent total stored energy.

This is why direct and precise comparison is not actually possible unless we can be sure that all test conditions were absolutely equal. Even testing the same car under roughly the same conditions, we might not be able to detect any real change in battery performance until it has reached a level of being "plainly" obvious (e.g., one might be able reasonably detect, say, a 10% or larger change in performance, but there is probably just too much "noise" to reliably detect anything smaller).

 

[sefs]

I had a similar experience. I was down to 17.9 kWh before about 1% battery. It ended up being battery capacity miscalculation. Here is the gold standard for checking capacity: Fully charge the battery. With the car in your garage, turn it on and reset the trip meter. Roll down the windows, and turn the HVAC on max defrost. Turn off the rear window heater. Let the battery go all the way till the contactor opens. This will take a couple hours. This will be when the Ready to Drive green car goes away, not just when it says stop safely now. In my case, stop safely now occurred at 18.1 kWh, the contactor didn't open until 19.4 kWh. It was all battery capacity miscalibration.

Sefs - What a great post. Thank you for finding a way to create a load without driving.

I'm trying to settle this in my head a bit, thinking through what's going on.

This test has to be pretty hard on the battery - you're taking the batteries down to zero charge, or really low charge. That can't be good for the batteries. Not a big deal to do this a few times, but a guy wouldn't want to do this a lot. Did I get that right?

If you think temperature is important, then doing this right after a full charge would be really important. That's when the batteries will be warmed up or cooled down from charging. They will be a consistent temperature. That pack is pretty darn dense, especially inside the car. I'm not sure 24 hours in a garage is going to get everything to the temperature you think.

I'm just thinking initial battery temperature should be monumentally irrelevant (for this test). The TMS will warm or cool the battery to whatever temperature it thinks is correct or best for the battery. The energy used to get there will be counted in the final reading at the end of the test. You don't care if the energy was used to run the HVAC, run the radio, or cool / heat the battery. You're just looking for a really fast heavy energy use to run the battery down in a reasonable amount of time.

Guess the temperature issue just goes away - if the battery starts out at 30 degrees, the car is going to warm up the battery to something higher, like maybe 50 or 60 degrees. If the battery gets warm, the car will cool it off. All that energy will be counted in the total used, right along with the energy to run the defroster.

So you start out with a fact - this test tells you the battery has this many kWh available. If it is only 16 kWh - then there is a problem with the battery. If it is near 20 - then the battery is fine.

How those kWhs translate to miles on the road is a totally different discussion.

This test is pretty harmless to the battery. Yes, it is introducing another cycle, but as long as you don't do it weekly, I would be shocked to see a significant change to the battery.

Initial battery temperature is very important to this test. The TMS will only heat the battery up to 50F while charging, and it will not heat the battery at all while not plugged in. I will check my internal battery temperature after a full charge, but my I'm not sure if this will have elevated it enough during the winter to get to about 70F internal temperature. To get a nominal reading, I wouldn't suggest anything lower than a 70F internal battery temperature. I have even seen capacity reduction at 55F. In my case, I would probably set my garage heater to 80F and let the car sit in there for 24 hours.

I have bypassed the pack heater relays to manually turn them on, but they shut off after about 55F even in this bypassed mode.

I don't think the battery will warm from 30F to 50F or 60F by a 6 kW load.

How about instead of thinking, I get you guys some real data :lol:
I'll try to conduct this test tomorrow or Christmas morning.