Ioniq 6 efficiency
 

Just a few observations on the highway efficiency of the big battery dual motor I6. I have a very consistent 65 mile commute to work and am usually within 1% battery deviation for each commute historically. Typically I set my cruise control on 84mph(radar detector used), use the A/C, and do minimal following. Basically an EV battery nightmare commute. I am always starting at 100% as I charge at home and at work. For this commute I typically arrive to work at 68/69% battery and estimated 2.7mi/kwh efficiency rating. Today I had the ability to come in late so I decided to focus on efficiency above all else. I drafted an 18 wheeler at a close but safe distance for virtually the entire ride at between 66 and 70mph, no A/C (front flaps closed), no cruise control. Zero electric braking. I was pleasantly surprised that I arrived to work, mildly sweaty, with 82% battery, 4.2mi/kwh. By reducing the speed approximately 20%, the car was 56% more efficient. At least is my HS math is correct anyway.

Since I'm a penny pincher, I'd probably only charge at work.

To maximize battery longevity, it's recommended to not charge to 100%, or discharge too deeply.

As a side note: 100% charge indicated might be only 85% actual possible charge. I can cram another 12% into my Volt pack if I don't care about battery life. Otoh, the 12% didn't get as much added range, or motor power.

Unsure about deep discharge other than the possibility of forming battery shorting dendrites from the lithium oxides. At a point below 50% charge the ranger gets so gutless it wouldn't make it up the driveway at home at a 2% grade. Good thing your electronics won't let you get there.

Usable vs total battery capacity varies based on the automaker and even model. Unfortunately in the USA automakers don't have to tell us both of those critical specs but we do have info on European models.

The European Ioniq 6 has a 77 kWh battery with 74 kWh usable = 96% usable.

This is a source of that info:
https://www.evspecs.org/tech-specs/h...long-range-awd

You can calculate actual maximum theoretical capacity depending on if you have access to knowledge of cell voltages after charge. Wouldn't use facebook data. Dont trust vehicle manufacturers. 96% charge isn't gonna get you long life, supposedly.
Otoh, that 12% extra useable I can get doesn't offer any advantages except a wee bit of extra range and didn't seem to measurably reduce cell life much in an early Volt pack. Have 11 years use on it, 16,000 city miles, will advise when they do fail.

Manufacturers have been steady removing reserve battery capacity. 95% is pretty typical today. That is a far cry from the 25 - 30% some of the early EVs had. (Of course they also tell owners not to charge to 100% on a regular basis)

My Bolt has 10% in reserve - 5% at the top and 5% at the bottom of the SOC.

' by reducing the speed '
 

1) On the Chevy Bolt, if the old national 55-MPH speed limit constituted 'one-car's ' worth of energy consumption:
2) By 73-mph she'd be consuming two-cars worth.
3) At 84-mph, three-cars.
4) And, at 93-mph, four-cars.
It really 'tells' on the velocity-cubed relation to aerodynamic power needs.
5) At 45-mph, the BOLT will go over 496-miles on the 'recall', 66-kWh pack.
6) At 45-mph, the IONIQ 5 will go 546-miles.
7) At 45-mph, the IONIQ 5, with the IONIQ 6 body, will go 638-miles.
8) At 45-mph, the IONIQ 5, with the GM Aero 2002 body will go 769-miles.
9) At 45-mph, the IONIQ 5, with Cambridge University Eco Racer ( CUER ) 'Revolution' body, will go 844-miles.

Unfortunately there are only two chargers at my job, (max 7.7kw/hr) and as I generally work three 12 hour shifts in a row, if I don’t have the opportunity to charge at work-the battery drain will accumulate until I’d be discharging below 40%. I don’t charge to 100% in extreme temps. I’ve kind of decided that charging to 100% on a low output charger is the better option from a deep discharge but I understand your pov.

I’m not sure I totally agree with the comment regarding SOC accuracy, at least on a contemporary EV. I do the same trip dozens of times per month, at the same times of day, etc and the SOC is virtually identical every trip. I’ve noticed the I6 is very consistent in estimating battery % but less so on the mile/kWh figure. That figure may range between 2.5 to 2.8 trip to trip but the total battery percentage is virtually identical. I’m going to begin toying with its aerodynamics a little bit but I think it’s very close to its least draggy right out of the box.

To continue my OT comment about penny pinching, I discovered free 9kW chargers 15 miles away, so I've started plugging in there while I run for an hour or so. Then I take a lazy cool-down walk, and then do the web-surfing I would normally have done when I got home. In 2hrs, I end up banking about 10% more charge than I used roundtrip.

Regarding 12hr shifts, I'd think getting access to a charger at some point during that timeframe would be very likely. There's no worry charging while hot since your car has active thermal management. I'd have no concerns about charging to 100% assuming you're not leaving it fully charged for days.

I'd have killed for a 3kW charger at my work when I had the Prius plug-in. It would have allowed me to complete trips in EV only mode in the winter. Instead, I'd have the engine fire up for 1 mile, not get up to operating temp, and then shutoff when I parked in the garage.

You are demonstrating the holy grail of testing: accurate repeatable data. Might be totally wrong but the data is testable with precision. Mile/kwh is environment dependent which varies all over the place.