Its starting to get cold outside. How's your range doing

[michael]

I would imagine that's pretty much the case unless it's so hot or so cold the TMS kicks in, and it's plugged in.

In my case, I value charge shortly before departure so the battery is somewhat warmed up. It was around 50 F this morning but my battery was in the low 70's

 

[hybridbear]

After my FFE has sat around for a while (overnight) doing nothing (not even charging) the HV battery temp always seems to end up within a few degrees of the ambient temp.

Is that what everyone sees?

I suppose that would make sense. Given enough time, all parts of the car should settle at the ambient temp (assuming covered in a garage).

That's what we see.

In my case, I value charge shortly before departure so the battery is somewhat warmed up. It was around 50 F this morning but my battery was in the low 70's

Our Value Charging starts at 3:00 am. Usually the car is charging for less than 1.5 hours. When it's done by 5:30 am & we don't leave until after 9:00 am, the HVB has usually returned to near ambient temp. If the car is charging longer or we are leaving earlier, the HVB temp is higher.

 

[hybridbear]

My typical starting GOM prediction has dropped with the falling temperatures. In the summer it usually shows 97-102 miles when fully charged. Now it's showing about 85-91 miles when fully charged. Those are HVAC off range predictions. By the time winter fully sets in, the typical HVAC off GOM prediction on a full charge is around 70-75 miles.

 

[michael]

NREL published a paper that said in one test:

The capacity increases at higher temperatures and drops at lower temperatures. At 40°C, the capacity increased 6% from ambient (7 Ah) to reach a maximum near 7.4 Ah, and at 0°C, the capacity decreased 15% from ambient with a maximum capacity of 6 Ah


Of course, we are more concerned with kWh than with Ah, but this will give some idea of the changes people have seen with temperature.

 

[michael]

This morning my useful capacity was about 15 kWh. My consumption rate was high (about 350 Wh/mi) due to high speed and use of the heater. This caused me to form the impression that the effects of low temperature may be greater on an older battery than on a new one.

This makes some sense...as the battery fades, not only does it lose energy capacity, but also the effective series resistance goes up. Cold temperatures possibly aggravate the increase in ESR, so the available energy drops more with low temperatures than it does in a new battery.

Anyone else seeing something like this?

 

[Dstiedeman]

Has anyone tried using a power inverter from the 12v socket and then plug a small space heater into the inverter to warm up the cabin? Lasko makes a cheap ceramic space heater that only uses 200watts so the effect on range should be minimal. Do you think it would drain the 12v car battery too much?

 

[jmueller065]

You'd be better off using a 12V heater rather than running an inverter:
http://www.amazon.com/Roadpro-12V-Heater-Swing-out-Handle/dp/B000IXTGHW

You'll have some losses through the inverter and thus won't be able to heat as much as a 12V one.

My coworker uses something similar to the link above to keep his windshield defrosted in the winter.

Keep in mind that the fuse on the cigarette lighter plug is only about 15 Amps so you can only get a most about 15*12 or 180 watts out of the thing.

 

[dmen]

28 steady sunny degrees today. I had to make a 73 mile drive so I hit the road without using cabin heating and planned to see how far I'd go before needing to charge and/or warm up. To my surprise I was able to do it without stopping to charge, and was even able to use a little heat on the home stretch.
Initial GOM was 80 miles; lowest was that I'd be 7 miles short. Later part of the drive was a lot of city streets and slow highway, so I gained them back. I cranked the heat for the last few miles and in the garage to draw down to 0, when the trip meter reported 17.1kWh. My car is at 25000 miles and 35 months. A month and 500 miles ago in 60 degree weather I measured 18kWh capacity.

 

[triangles]

WOW! good job dmen. I wouldn't have believed that was possible.

 

[breeves002]

Yesterday it was below 20 degrees here. I had remote started on AC to help warm it up. I ran the heat at 72 degrees my entire 15 minute drive. GOM said 50 miles from the time I left. I don't remember what it said when I got there, but I had lost about 15% battery. One thing I noticed was how quickly it recharged. I left with 95%, got there with 80%, and L1 charged. It was charged after only just over 2 hours. That seemed really fast to me. Anyone else find that weird?

On another note I saw my first FFE in the wild! White 2012-2014 in Chesterfield, MO.

 

[hybridbear]

We only have 19,000 miles & we're seeing a major loss in range compared to last winter. Specifically, once the HVB charge is below about 15% displayed, the charge drops really fast. Friday night we were 6.3 miles away from home with 11% charge displayed remaining. It should have been no issue to get home. The ETE reported about 2.05 kWh. This particular drive we make multiple times a week and it takes 1.2-1.5 kWh without using HVAC. We started driving with the HVAC off. After about 2 miles we were down to 0.6 kWh remaining ETE & 4% displayed SOC. We had to stop & charge. Fortunately there's a free L2 EVSE at Goodwill that we drive right by on our way home. We stopped and charged for a few minutes there & made it home.

Yesterday I began a 6.4 mile trip home with 12% displayed SOC & about 2.25 kWh ETE. I should have been able to use heat, as the outbound trip from home only used 1.2 kWh & there's no real elevation change. I hit the SSN about a block from home. The trip home used 1.5 kWh according to the MFM trip log, but used up 2.25 kWh of ETE. The ETE hits 0.000 kWh just after the SSN message appears.

This morning my wife started with a full charge & drove to work. She used 1.5 kWh according to the MFM trip log, but she used up 10% of the displayed SOC. Normally her trips to work use up about 7-8% of the displayed SOC. I'm very concerned about how we're going to get through the winter.

 

[michael]

I'm sorry you're seeing the same sort of thing I am, although mine is less severe. I have a lot more miles but much milder temps.

I have the impression that battery fade is seen to a greater degree in cold weather than in warm. This makes some sense, I think....a fading battery experiences both capacity fade and power fade. Power fade is in effect an increase in effective series resistance. So possibly as the battery ages, not only does it lose capacity, but it wastes more energy to ESR, especially in the cold.

My other impression is that the ETE estimate (which is the basis of the battery percentage display) is out-to-lunch. The displayed battery percentage seems to be whatever is the current ETE divided by the ETE at the end of the last full charge. Neither one seems correct to me, so it doesn't surprise me that the percentage is unreliable.

In my case, the ETE after charge is substantially less than the actual available per trip meter; and the ETE falls rapidly early in the discharge cycle. What your wife observed is the same sort of thing...ETE (and therefore percentage) fall disproportionately in the first few miles.

If you have FORSCAN, see if the cell variance gets large near the end. You might have a few weak cells, or even just one. I suspect the car says "I'm done" when the first cell hits minimum, even if all the others are doing OK. If this is the case, possibly warranty will cover it???

 

[shniestEV]

Hi All,
Im new to the forum and haven't received my FFE yet. Is there anyone in the pacific northwest that can share battery and range details I should expect once i take delivery?
I live in Vancouver, Canada we often don't go much below 32F (0C). My round trip commute is around 40 miles (65km).

Hybridbear mentioned "We usually see about 85-95 miles of summer range & about 60-65 miles of winter range. 65 km should be doable year-round."

In the north west its normally raining and around 35F on a bad day in the colder months. Safe to assume 40mile round trip is a cake walk with lights, heater and wipers on?

Thanks!
Keith

 

[WattsUp]

In the north west its normally raining and around 35F on a bad day in the colder months. Safe to assume 40mile round trip is a cake walk with lights, heater and wipers on?

Lights, wipers, radio use next to nothing. It's the heater that will get you (5 kW or more at full tilt). But with only a 40 mile round trip you should be fine in any weather.

 

[jdorff]

I have 37K miles on my 2013 FFE. I reset the trip meter every morning at full charge. I get about ~15.5-16 kWh before it's depleted . I've hit the "Depleted Battery Stop Safely now" message twice recently, but managed to coast home. I wish I had known about the kWh setting on the trip computer and had done a full charge to empty test when new. I don't know how much my battery has degraded, but I'm having more range issues. I'm glad the lease is about up.. wish the "100 mile" FFE has available now.

BTW, I'm not a big fan of the "Stop Safely now" behavior. If I need to stop at a traffic light or stop for traffic, it leaves you stuck in the road.

 

[michael]

Your car is a little older than mine but has somewhat fewer miles, and the useful charge is pretty much the same. Yours is maybe a little better.

Looks like both age and miles take a toll, pretty much what the NREL models have shown all along.

These batteries fade just like all the rest. I really, really hope the upcoming 100 mile Focus includes the ability to optionally use the battery in a long life, low stress mode rather than wearing it out needlessly on days the full range isn't needed.

I think Ford played the same game with the battery that all automakers seem to play with fuel gauges...they don't fall much when near full and then fall faster later on. Based on the INL testing, the batteries, when new, are bigger than the rated 23 kWh. Accordingly, the first increments of fade are not apparent. INL tests the actual capacity of the battery and reveals the initial losses.