2.6 M/Kwh not possible?

[SD39U]

I’ve been driving my Lightning for about 18 months now, and one thing that I have noticed on my daily trip is that I never can achieve 2.6M/KWh. I can do 2.5, I can do 2.7, but the truck will never show 2.6. Why?

Antone else notice this?

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[MountainAlive]

Must be the forbidden efficiency.

 

[Athrun88]

Conspiracy by Big Numbers to confound the everyday EV driver

 

[Refactoringdr]

I've noticed this for a long time. If you look at the "Trips" app on the center screen, you will see those "forbidden" values. I'm of the opinion that the instrument cluster display truncates to 1 decimal position and the center rounds correctly to 1 place. (Software dev here) So I'm guessing that the higher precision values are something like 2.50, 2.59, 2.70, or something like that. Rouding would give you 2.5, 2.6, 2.7, but truncating gives you 2.5, 2.5, 2.7.

Disclaimer: I'm talking out my butt, but that doesn't mean I'm wrong.

 

[richguy82]

Does anyone who lives in Florida get anything better than 2.2??? I think my average for the last 1600 miles or so is 2.1. I don’t do a ton of highway driving.

 

[K6CCC]

Not in Florida, but 2.3 since I bought my truck - 20,635 miles. Lots of local drives are higher than that, but long trips tend to be lower (high speed kills range).

 

[The Weatherman]

It’s been discussed here before (a year or two ago) that there some numbers that will not display. That one sounds familiar to me.

 

[jobofly79]

Yep same here. Always jumps between 2.5-2.7

 

[Bushwood CC]

I started that same thread a year ago. Best answer was that 2.6 in some coding language means something specific and the truck could misinterpret that. That made more sense than anything else.

 

[3rdgenfan]

You're either too efficient or not efficient enough, sorry.

 

[SpaceEVDriver]

I've noticed this for a long time. If you look at the "Trips" app on the center screen, you will see those "forbidden" values. I'm of the opinion that the instrument cluster display truncates to 1 decimal position and the center rounds correctly to 1 place. (Software dev here) So I'm guessing that the higher precision values are something like 2.50, 2.59, 2.70, or something like that. Rouding would give you 2.5, 2.6, 2.7, but truncating gives you 2.5, 2.5, 2.7.

Disclaimer: I'm talking out my butt, but that doesn't mean I'm wrong.

I don’t think you’re entirely wrong.

I think maybe it’s truncating in the binary representation's fractional part (two bits maximum for the fractional part) of the km/kWh calculation, rounding or truncating in the conversion from binary to decimal, and then rounding or truncating in the conversion from km to miles. I haven't tracked to check if other values are missing from the display, though.

Binary representation of km (whole part . fractional part)	km (decimal)	Miles (rounded up to one decimal place)
11.00	3.0	1.9
11.01	3.3	2.0
11.10	3.5	2.1 or 2.2 (is one of these never seen?)
11.11	3.8	2.3 or 2.4 (is one of these never seen?)
100.00	4.0	2.5
100.01	4.3	2.7
100.10	4.5	2.8
100.11	4.8	3.0
...	...	...
1111.11	15.8	9.8
10000.00	16.0	10.0

 

[Electric Messiah]

I’ve been driving my Lightning for about 18 months now, and one thing that I have noticed on my daily trip is that I never can achieve 2.6M/KWh. I can do 2.5, I can do 2.7, but the truck will never show 2.6. Why?

Antone else notice this?

It's the equivalent of missing Floor 13 in superstition ridden hotel design.

 

[zakress]

I don’t think you’re entirely wrong.

I think maybe it’s truncating in the binary representation's fractional part (two bits maximum for the fractional part) of the km/kWh calculation, rounding or truncating in the conversion from binary to decimal, and then rounding or truncating in the conversion from km to miles. I haven't tracked to check if other values are missing from the display, though.

Binary representation of km (whole part . fractional part)	km (decimal)	Miles (rounded up to one decimal place)
11.00	3.0	1.9
11.01	3.3	2.0
11.10	3.5	2.1 or 2.2 (is one of these never seen?)
11.11	3.8	2.3 or 2.4 (is one of these never seen?)
100.00	4.0	2.5
100.01	4.3	2.7
100.10	4.5	2.8
100.11	4.8	3.0
...	...	...
1111.11	15.8	9.8
10000.00	16.0	10.0

This is like why iPhones will not display 69°. It’s more than likely a conversion from metric to customary units that just doesn’t display it, ever.

 

[Prof’s Lightning]

I have hit over 3.0 on several trips but only in mild weather

 

[DNap4]

mi/kWh depends on driving habits, external ambient temperature, internal energy usage (AC/Heater), speed, wind, elevation gain/loss, regenerative breaking. Highway is a killer.

I drive short distance city driving 200+mi/wk and average 2.5-3.8 mi/kWh at 70-90 degrees in central VA. My last trip was 3.1mi/kWh on a 14 mile drive and before that 3.8mi/kWh on a 10.5mi drive. Most of the time it's around 2.7-3.1mi/kWh city driving going between 30-55mph. It's going to depend on where you live. If you're in the south, is your cabin temperature set very low so AC is running? Are you driving up/down hills frequently in your drive? How fast are you driving and are you using regenerative breaking? There are so many factors that affect mi/kWh

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