Weird energy consumption oddity.

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FloridaSun

FloridaSun

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I live in Florida and my area is completely flat. I commute to and from work on I-4. I also frequently drive to Orlando on I-4. Over several months, I have observed that my efficiency is worse when driving West to East and better when driving East to West. I usually blamed it on wind but today I put it to the test. Today it is very calm, no wind whatsoever. I drove approx. 27 miles from exit 28 in Lakeland to Exit 55 in Davenport. I had the cruse control set to 70 mph. and I reset the trip odometer upon entering the interstate. When exiting at exit 55, my efficiency showed 3.9 miles/kwh.
On the way back, I did exactly the same.. Upon entering I-4 at exit 55, I reset the trip odometer and when I exited at exit 28, my efficiency showed 4.2 miles/kwh.
I looked at topographic maps of the area and there is no significant change in altitude. There was no wind.. I have no idea how it is possible that CONSISTENTLY, my efficiency is different depending on the direction I drive on a completely flat highway..

Just to note, AC was OFF both ways and I was running WAZE via Android Auto.
 
The only other variable I can think of is temperature which even small changes would have an effect on a tire's rolling resistance. I don't think it would have that much of a change in your situations but that is all I got :)
 
electriceddy said:
Possibly higher battery temperature on the return trip, reduced capacity when cooler
https://batteryuniversity.com/learn/article/discharging_at_high_and_low_temperatures
The only way to prove that is to start the same trip from Davenport to Lakeland and then return back to Davenport
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I only spent 15 minutes there. Temperature difference was about 3 degrees.
I observe the same on my morning commute to work (east to west) and back home (west to east).
Despite the headlights being on in the morning, I always get .3 better efficiency going to work in the morning and worse at 3:30 pm when driving home. It is hotter on the way home.. (of course only comparing the efficiency with the AC off both ways.
 
Yeah, small influences will result in that. Your difference is also only 0.3 miles per kWh, so that is very little as well. Even very small changes in elevation will have an effect. It might be more reasonable that outside temperature will make the difference here. If you have a slightly higher temp on one way, like always driving in one direction in the morning and then back in the afternoon, the higher temp will have an effect. Warmer temp is less dense, so less drag.

Sent from my moto x4 using Tapatalk
 
Esprit1st said:
Yeah, small influences will result in that. Your difference is also only 0.3 miles per kWh, so that is very little as well. Even very small changes in elevation will have an effect. It might be more reasonable that outside temperature will make the difference here. If you have a slightly higher temp on one way, like always driving in one direction in the morning and then back in the afternoon, the higher temp will have an effect. Warmer temp is less dense, so less drag.

Sent from my moto x4 using Tapatalk
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It is hotter when I drive home from work compared to my commute to work in the morning and I get better efficiency in the morning. Today, it was hotter coming back from Davenport and I got better efficiency in the hotter temperature.
As far as I can tell, the altitude difference is less than 20 feet between highest and lowest point on the trip which should not make a difference.
 
BlueKonaEV said:
I only spent 15 minutes there. Temperature difference was about 3 degrees.
I observe the same on my morning commute to work (east to west) and back home (west to east).
Despite the headlights being on in the morning, I always get .3 better efficiency going to work in the morning and worse at 3:30 pm when driving home. It is hotter on the way home.. (of course only comparing the efficiency with the AC off both ways.
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I find myself to be at least .3 better efficient going to work in the morning and a lot worse when driving home, also varies with temperature.:D
 
electriceddy said:
Possibly higher battery temperature on the return trip, reduced capacity when cooler
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It might be worth noting that it's the battery capacity that is compromised by cold temperature. In this case the numbers represent the energy draw rate, which should not be affected by battery capacity. Clearly though there are other temperature influences such as gearbox oil viscosity and air density.
 
electriceddy said:
I find myself to be at least .3 better efficient going to work in the morning and a lot worse when driving home, also varies with temperature.:D
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It's not just at certain times.. It's consistently a worse efficiency when driving east compared to driving west on I4.... It's really weird..
 
KiwiME said:
Well, this graph came from Hyundai according to this article. But I don't think that's the exact issue in this thread.
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It may be a little off topic, but i am baffled by what the OP is reporting, and temperature seemed like it might be relevant.

Maybe pavement conditions are different in the EB and WB lanes?


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KiwiME said:
Well, this graph came from Hyundai according to this article. But I don't think that's the exact issue in this thread.
View attachment 6299
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I doubt that the temperature has anything to do with it. This phenomena happens every time. I wish that I could find a more detailed topographic map of I4 even though I doubt that this is the problem. One thing that impacts efficiency is the amount of traffic.. If there are more cars on the road, it does create some amount of suction, just like when you are tailgating.
I actually have observed exactly the same phenomena with my wife's gasoline van. Every time, we go to Houston and we travel on I-10 between Lake City/FL and Houston, the gas mileage going from Lake City to Houston on I-10 is at least 1 - 2 mpg better than going from Houston to Lake City. You start and end at about the same elevation. There are "hills" on I-10 and as you are not recovering lost energy on the way downhill, that may explain it. However, with an electric car, if you start and end at the same elevation, you should theoretically get the same efficiency going the same speed as your car will recover the energy it took to go up the hill when it is on it's way down.
 
BlueKonaEV said:
...However, with an electric car, if you start and end at the same elevation, you should theoretically get the same efficiency going the same speed as your car will recover the energy it took to go up the hill when it is on it's way down.
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Two things, regen has its loses, you might get 75% back, but not 100%. Second, open the desktop Plugshare website, go to the "Trip planner" part, add the start and end points and click the button to show the elevation profile. I tried this myself but I couldn't translate your exit numbers to locations without further research.
 
KiwiME said:
Two things, regen has its loses, you might get 75% back, but not 100%. Second, open the desktop Plugshare website, go to the "Trip planner" part, add the start and end points and click the button to show the elevation profile. I tried this myself but I couldn't translate your exit numbers to locations without further research.
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Thanks.. I will try that..
 
Just looked at plugshare elevations between Lakeland and Orlando and there is overall increase of 130 ft to Orlando. So uphill (slightly) to Orlando and downhill back to Lakeland
 
Fastnf said:
Just looked at plugshare elevations between Lakeland and Orlando and there is overall increase of 130 ft to Orlando. So uphill (slightly) to Orlando and downhill back to Lakeland
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Opps I got that backwards Lakeland is higher than Orlando by 130 ft.
 
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