TrojanEV
Posts: 43
Joined: Mon Nov 10, 2014 4:49 pm
Location: Los Angeles, CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 9:35 am

So when I got in my fully charged Focus this morning, the Guess O' Meter said I had 63 miles to empty. Is this normal, considering the advertised range is 76 miles? Is it making some adjustment for how I have driven it so far? After driving a couple miles to work, it now says 59 miles (98%).

Thanks! (I figured this thread seemed as good as any to post questions, rather than start up an entirely new one)
2014 Blue Candy FFE

WattsUp
Posts: 2113
Joined: Mon Jan 07, 2013 2:58 am
Location: SF Bay Area, CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 10:03 am

TrojanEV wrote:So when I got in my fully charged Focus this morning, the Guess O' Meter said I had 63 miles to empty. Is this normal, considering the advertised range is 76 miles?
Maybe. It depends on what your recent driving patterns and climate control usage were and what your (resulting) average Wh/mi is.

At 63 miles on a full charge, I would say that your current average Wh/mi must be somewhere around 300.

19 kWh / 63 miles = 301 Wh/mi
2013 FFE, Platinum White, Delivered January 2013
2017 MS, Midnight Silver Metallic, Delivered February 2017
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TrojanEV
Posts: 43
Joined: Mon Nov 10, 2014 4:49 pm
Location: Los Angeles, CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 11:02 am

WattsUp wrote:
TrojanEV wrote:So when I got in my fully charged Focus this morning, the Guess O' Meter said I had 63 miles to empty. Is this normal, considering the advertised range is 76 miles?
Maybe. It depends on what your recent driving patterns and climate control usage were and what your (resulting) average Wh/mi is.

At 63 miles on a full charge, I would say that your current average Wh/mi must be somewhere around 300.

19 kWh / 63 miles = 301 Wh/mi
Still figuring out the MFM app, but stumbled upon my usage statistics so far. Your estimate of my Wh/mi was actually more generous than reality. Yesterday (my first full day with the car), I drove 11 miles and averaged 372 Wh/mi. :o Most of the distance came from driving highway miles at about 70-75mph, with the AC on pretty high. I guess I need to start channeling my eco-friendly, zen, driving style. I've previously only owned ICE vehicles, so my bad driving habits may take some time to kick.
2014 Blue Candy FFE

cwstnsko
Posts: 171
Joined: Sun Apr 27, 2014 12:10 pm
Location: Winnipeg

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 11:59 am

TrojanEV wrote:.... I've previously only owned ICE vehicles, so my bad driving habits may take some time to kick.
We've all been there :-) If you commute is such that you don't need the range, then don't sweat it, just enjoy the car to its fullest. That said, it's a really good idea to spend a bit of time being artificially conservative to learn the techniques for maximizing range, for those days when something happens and you need to stretch it out.

I started tuning my driving style when I dropped the SUVs in favor of more economical ICE vehicles, but in an EV, you become dramatically more aware of the effect of your driving style on economy.

I do love that my 30 mile round trip commute allows me to drive any way I like with the climate control set however I want :D
Chris W
2015 C-Max Energi, Magnetic, 302A package
2014 Focus Electric, turned in at end of lease

TrojanEV
Posts: 43
Joined: Mon Nov 10, 2014 4:49 pm
Location: Los Angeles, CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 1:11 pm

cwstnsko wrote:...I do love that my 30 mile round trip commute allows me to drive any way I like with the climate control set however I want :D
Well, I guess I can really go hog wild then, given my 2 mile round trip commute to work! :lol:

But, as you said, I already have a few plans to stretch out the range, so I better start practicing now for when I need it.
2014 Blue Candy FFE

WattsUp
Posts: 2113
Joined: Mon Jan 07, 2013 2:58 am
Location: SF Bay Area, CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 1:23 pm

TrojanEV wrote:Most of the distance came from driving highway miles at about 70-75mph, with the AC on pretty high.
The speed is what did it. The A/C doesn't use much energy. (Heat does though.)

Sustaining 75 mph takes a lot more energy than sustaining, say, 65 mph. At either of those speeds through, wind resistance overwhelms every other factor (except for perhaps blasting the heat on full constantly). Wind resistance also increases exponentially with speed. So, slow down even just a little bit, and your overall range will increase exponentially (relative to the reduction in energy consumption).
2013 FFE, Platinum White, Delivered January 2013
2017 MS, Midnight Silver Metallic, Delivered February 2017
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davideos
Posts: 406
Joined: Mon Jan 21, 2013 8:58 pm
Location: So Cal

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 2:03 pm

Just to backup Wattsup, the resistive force from drag is proportional to the square of the speed. F=.5 * air density * speed^2 * drag coefficient * cross sectional area.
The drag coefficient is related to the shape of the FFE. It is just under .3.
Air density changes based on barametric temp, altitude, humidity, temperature, etc; but is about 1.25 kg/m^3.

The force, or power, to overcome drag is P = F(from above) * V; which means that the force to overcome the drag is proportional to the cube of the speed. Stealing from Wikipedia: "A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power."

Fun stuff

TrojanEV
Posts: 43
Joined: Mon Nov 10, 2014 4:49 pm
Location: Los Angeles, CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 4:52 pm

Wow, this is great stuff! I love it, although I can already see my wife rolling her eyes as I excitedly try to explain it to her. :)

I'm thinking a good way to force myself off my ICE habits will be to use cruise control (when safe, of course) to keep me at 65mph (max) on the freeways.
2014 Blue Candy FFE

NightHawk
Posts: 535
Joined: Fri Sep 26, 2014 10:20 pm
Location: Southern CA

Re: My random thoughts/comments/questions/concerns as I go

Tue Nov 11, 2014 5:03 pm

TrojanEV wrote: I'm thinking a good way to force myself off my ICE habits will be to use cruise control (when safe, of course) to keep me at 65mph (max) on the freeways.
Yep that definitely helps, also try even lower at 60mph or even 55mph if you can and watch the displayed Wh/m line and compare.
2014 Ford Focus Electric - Oxford White, Cloth Seats (Lease ended 9/28/2017)

blackbeasst
Posts: 143
Joined: Mon Jun 02, 2014 5:00 am
Location: GA

Re: My random thoughts/comments/questions/concerns as I go

Fri Nov 14, 2014 4:48 am

soooooo, after a week of semi cool weather here in ga im starting to see some trends. mainly my mileage is starting to decrease. normally i get to work i have 40ish left of the GOM (guess o meter). now that the weather has turned im rolling in at 34-35. which really puckers my butt cause its a 35 mile drive back home.

driving the same speed, the same way, with no climate, starting out with pretty much the same mileage on the GOM in the morning, what would cause it to dip so much?

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