How pessimistic is the Mi/kWh display on the dash?

[TaxmanHog]

The issue is the tenth of an MPK between the IPC & the Sync screen, that simple.

We've beat the BMS theory to death in other threads and BTW to OP, we've also discussed at the tenth issue in other threads.

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[GoHawks]

I appreciate the insights. I had never noticed the discrepancy before and generally rely on dash display vs the 15” screen display. Realizing potential different inputs and different calculations depending on the owner of that feature implementation is the most likely the cause between the display differences. I had not run across that discussion in the forum prior. I also understand the ‘energy’ held or used by the battery differs depending on a lot of variables (temperature, etc.) and could affect the results.

Has anyone ever done a deeper dive into how pessimistic the mi/kWh display is? I understand it is an average, but using accurate kWh consumed (start and end value) during a trip divided by miles driven? Is the average display very close, generally under by x% or variable both + and - depending on the day.

I am happy to let the thread die, but was generally curious and differing display values made me think a little bit more about the topic.

 

[TaxmanHog]

I always use the pessimistic value for my on the fly computations & validation of progress, better safety margin for long runs and running your SOC low.

 

[mb0220]

In my experience, the mi/kWh is pretty bang-on accurate. What conerns me is that the GoM is ALWAYS optimistic. I do understand the inherent flaws in the GoM and I definitely don't live my life by it. I just expected that the inaccuracy should spread somewhat evenly between the high side and the low side.

 

[HHI-Lightning]

@mb0220 - that’s the exact opposite of my observations.

Just drove 350 miles yesterday with my ‘23 Lariat ER. Flat Interstate driving, I-95 thru North and South Carolina. Cruise set at 65 the entire duration. Temps 66-75. No notable wind or adverse weather

Mi/KwH shown on display was about 7-8% under reported. (Display showing 2.1 when actual was about 2.3)

GOM is always significantly Pessimistic on available range. Charged to 80% at DCFC, GOM shows range of 180 miles. Actual range should have shown as 240 miles.

I find in flat highway driving, keeping speed in the 65 - 70 mph range, 65 - 75 degrees outside, normal wind, I can consistently get 30 actual miles out of each 10% of the ER battery.

10% of 131 KwH = 13.1. 30 miles / 13.1 =2.29 miles / KwH

 

[Zprime29]

@mb0220 - that’s the exact opposite of my observations.

Just drove 350 miles yesterday with my ‘23 Lariat ER. Flat Interstate driving, I-95 thru North and South Carolina. Cruise set at 65 the entire duration. Temps 66-75. No notable wind or adverse weather

Mi/KwH shown on display was about 7-8% under reported. (Display showing 2.1 when actual was about 2.3)

GOM is always significantly Pessimistic on available range. Charged to 80% at DCFC, GOM shows range of 180 miles. Actual range should have shown as 240 miles.

I find in flat highway driving, keeping speed in the 65 - 70 mph range, 65 - 75 degrees outside, normal wind, I can consistently get 30 actual miles out of each 10% of the ER battery.

10% of 131 KwH = 13.1. 30 miles / 13.1 =2.29 miles / KwH

That jives with my experience as well. Though it's hard to drive on the slower side for hours at a time. I always end up creeping faster after an hour or two.

 

[Scorpio3d]

Something new I noticed on my commute today - differing displays and calculations for mi/kWh. I do not use the GOM for anything and usually do the math when driving long distances. I have noticed using my ODBII device the dash display is generally pessimistic on what it shows once I do the calculation post trip. I attributed it to rounding but why do different screens in the truck show different results? Has anyone else done a deeper dive into specifics on this using data for measurements? If so, please provide results. That extra ~.1 or .15 mi/kHw might help change charging locations when traveling.

I have only noticed a .1 mi/kWh difference between the dash and iPad screens! Do others see more than this difference?

 

[TaxmanHog]

I have only noticed a .1 mi/kWh difference between the dash and iPad screens! Do others see more than this difference?

No, many of us have observed the 0.1 discrepancy

 

[Scorpio3d]

I like your "Bob" and "John" analogy. As an IT professional, my guess is that both screens are using the same data point, but for the display value the center screen Bob is rounding (1.87 becomes 1.9) while in the driver display John is truncating (1.87 becomes 1.8).

Still very annoying to those of us with moderate to severe OCD.

If you truly had OCD, you would call it CDO!

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