Battery Capacity

[Fluke]

I keep a log of my daily driving results with the FFE. Since new, I have measured the power consumed by the EVSE circuit and tracked it in a spreadsheet. More recently, I've been noting the after drive information from the trip meter in the car. One thing I have noticed is that the number of miles remaining as shown in the bar graph don't seem to line up with the car having available around 19-20 kWh. Following is information from one trip. The temperatures were in the low 20's in the morning and in the 30's in the afternoon on this commute trip and the average speed was around 35mph with maximum speed of 50mph on rural roads.

The round trip was 26.3 miles, car reported 5.8 kWh used, 220 Wh/mi and the F-E bar was about exactly at the 1/2 full mark at the end, the Budget was at 34miles (+1 status). From the charging circuit the car took 6.638 kWh to refill, so from the circuit actual measured power the car got around 252 Wh/mi consumption.

If this rate of consumption had continued, the battery's 19.5 kWh capacity should have provided a range of about 77 miles. But according to the estimated range info from the car, I would only be able to go a total of 60 miles and I would have used only about 13.2 kWh (based on 220Wh/mi) or 15.1 kWh (based on 252Wh/mi) before running out of battery.

So my question is had the trip continued, would I have been able to go closer to my predicted 77 miles or would I have topped out at the car's predicted max range of 60 miles? The car's predicted max range does not seem to make sense. Thoughts?

 

[WattsUp]

With those winter temperatures, were you running the heater?

Perhaps the kw/mi measured by the car does not factor in the climate usage, and so your prediction (of "capacity / Wh/mi" is too simplistic). It would make sense that non-travel usage is not included in Wh/mi (anyone know for sure?). However, we do know that the car's predicted range is affected by non-travel power usage (climate, etc.).

I suspect that the predicted range you calculated is simply not accounting for all the same things the car's algorithm accounts for.

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Update: Please see dmen's reply below... he has pretty good evidence that the Wh/mi reported by the car is affected by non-travel usage.

I'm a new FFE owner (took delivery about a month ago) and live in California and, although I sometimes do activate the climate system for a little heat, I've settled on 66 degrees, which sometimes doesn't even show up in the energy display, except perhaps right after I turn on. So, I don't yet have a lot of experience with "heavy" use of the climate system and how it can affect range.

 

[dmen]

Wattsup, the vehicle's Wh/mi displayed in the enhanced trip data view does include climate control use. My morning commute reliably shows 350+ when I run heating, vs 250 when I go without. Same traffic, same driving style, same route.

Fluke, unfortunately I'm pretty sure you would have ended up with 60 miles.
My experience with cold weather driving leads me to believe there are three factors that decrease range in cold weather. The first and probably biggest impact we all know comes from electricity used for cabin heating.
The second is battery warming. If I don't precondition the car on plug I will get a higher Wh/mi reading for the same trip at 20 degrees outside vs 40 degrees. I believe the vehicle is using some electricity to warm the battery pack as part of "thermal management." I haven't actually seen this confirmed in the manual/ online. Does anyone know for sure?
The third is effective capacity loss due to the cold. I think that despite thermal management, the battery isn't warmed to an ideal temp when it's below 30 degrees outside. So at those low temps, the battery just can't hold its charge as well. Again I haven't seen this stated by Ford, but my experience like Fluke's leads me to that conclusion. It reminds me of my old laptop- I charge it fully before leaving work, but if I leave it in the cold car overnight, the next morning the battery's flashing yellow when I boot up. I don't think it's an FFE-specific phenomenon, as it seems to be part of what happened with Mr Broder's Tesla DC-CT drive, giving him less range than predicted despite tame driving (Mr Musk's opinions notwithstanding).

 

[Fluke]

Thanks for the replies. I left out some of the details, I do not use heating except for the heated seats (this trip driver's seat was at 2) unless I'm uncomfortable. I used the preheating earlier in the year, but did not notice much of a benefit for range. The car was kept in the garage overnight, so it would have started out around 50F. Maybe preheating makes more of a difference when the temperatures get a bit colder, I'll have to try using it again when the temps are in the 20's or lower.

 

[jcjj]

I have had my car for only 3 weeks, but I think I might have an issue with my battery usable capacity. I live in Escondido, CA and temps have been in the 50's and 60's. I have been seeing 250-260 Wh/mile readings on my trips and can only use appox 16kWh of the Battery (64 Miles) before I get the "Battery Depleted" message or only have 10 miles remaining while only using 13.7kWh per the Enhanced Trip Gauge.

I took the FFE to my local Ford Dealer and they said everything was working fine.
I will now try to contact Ford, but not sure of the best way to contact them.

Has anyone else had this issue besides what Fluke experienced?

Fluke, Are you consistently seeing low usable range or was it just that one time?

Thanks,

 

[Fluke]

For the time being, I'm going to consider my car's performance to be likely due to the cold temperatures. I'll keep an eye on it as the tempertures (hopefully) start climbing up over the next few weeks. I have been able to go over 100 miles in warm weather, so I don't really think I have a battery issue unless it is something that recently developed.

In cold weather, the results I've posted are fairly typical.