Miles per wall kWh

Calculating that way mine is 3.78 over the course of 5500 miles. This includes some winter driving on snow tires.

 

But because nobody else is as honest as you, there's no way to compare actual-to-actual. However, your method produces the only reliable numbers. I doubt the methods of generating dashboard calculations are standardized among EV manufacturers so comparing those numbers is not very meaningful.

How long before VW gets called on the carpet for EV-gate? Just kidding.

 

Your honest math actually tracks better with the rather conservative EPA and NRCan net ratings (112 miles and 183 km, respectively).

 

Whilst I admire your efforts, it is not really overly useful to measure wall kWh efficiency, as the efficiency depends on how you charge it. A 10A wall socket only has 80ish percent efficiency. A 50kW charger may be more like 90%. This efficiency can be out of our control and can end up with wildly different results. The consumption of stored energy is the only repeatable test. Can you imaging if ICE cars had to report the diesel used transporting the petrol to the station? It makes no difference to the range calculation, only the cost. If you have say a 3miles/kWh wall to wheel efficiency, but a 4kWh battery to wheel, only one will tell you how far you car will go. I am not trying to belittle the idea, but just point out it isn't really useful except to calculate costs. You then need to adjust for temperature, charger type, preconditioning etc.

You can't really use wall efficiency to calculate range @SameGuy. Say you had a particularly terrible charger, which was only 50% efficient. You would use 60kWh to charge the MINI. You then do 160miles (actual range), divide by 60kWh (used to charge), to get the miles/kWh (2.66 by the way). Now with a 28.9kWh usable battery, that yields a range of 28.9*2.66 = 76 miles. So even though the test went 160miles, your range has been "scientifically" calculated at 76 miles. Hmmm, maybe you are on to something In the EPA test, the MINI actually managed 160 miles before the battery was depleted. After their fudge factors, that translates to 112 miles "real world range".

 

Fair enough For my personal situation, I either charge at home off peak on a 10A normal socket (around 80% efficient), or for free at a 50kW DC charger. Cost per km can vary wildly depending on the ratio of home to fast charger - between 0 and 2.6c(Australian)/km (power used at the wall). This represents 6.5km/wall kWh, or 8km/battery kWh. So in my case, as cost could be 0, I really only care about how far can I go - hence battery to wheel efficiency

Before anyone asks, the reason I don't always use the DC charger is it is about 10 mins from my house, so I trade a $5 home charge vs 20 minutes extra time. I charge at the DC if it is on my way to/from where I am going.

 

It bugged me when I read an Ioniq 5 owner reporting he gets 4.9-5 mi/kWh. How can a big heavy crossover get the same 5 mi/kWh number I get on my SE? I suspect the Ionic 5's computer is more optimistic than my SE's.

The only apples-to-apples comparison I know of comes from the pessimistic EPA, which rates the SE at 31 kWh/100 mi (3.2 mi/kWh) vs. the Ioniq 5 at 34 kWh/100 mi (2.9 mi/kWh). However, the EPA lists many cars that it rates as more efficient than the MINI Cooper SE (including, to my surprise, the Tesla Model S):

• 2022 Chevrolet Bolt EV: 28 kWh/100 mi.
• 2022 Hyundai Kona EV: 28 kWh/100 mi.
• 2022 Tesla Model S: 28 kWh/100 mi.
• 2022 Tesla Model Y Long Range: 28 kWh/100 mi.
• 2022 Chevrolet Bolt EUV: 29 kWh/100 mi.
• 2022 Kia EV6 RWD: 29 kWh/100 mi.
• 2022 Hyundai Ioniq 5 RWD: 30 kWh/100 mi.
• 2022 Kia Niro EV: 30 kWh/100 mi.

 

Just do some slow city driving and have maximum brake regen. I mean if you started at the top of the hill, after 30 feet you would probably have negative consumption.

 

The problem, and to be fair it isn't really the EPA's fault, is that manufacturers can do one of two things. They can perform all 5 tests, and get a "real" value for range/consumption, or they can do 2, and apply a fudge factor. One of the only manufacturers that do all 5 tests is Tesla. Their consumption figures are normally pretty close to real world. The EPA is the ideal test, so in the real world they are normally slightly lower, but very close.

Most other manufacturers, well the European ones at least, do the 2 test version and multiply by the one figure fits all - the magic 0.7. Now some cars, eg the Taycan or MINI are significantly higher than 0.7 - so the range, consumption are all quite a bit off. The Hyundais are quite accurate as well. I've had my SE for almost 2 years and in the entire time, my average consumption is 12.5kWh/100km (20.1kWh/100 mi.) . Now of course the temperature where I live, and my driving style might have an effect, but I would dare say not 50%. I drive about 40% at freeway speeds of 80-110kph, and the remainder at city speeds (0-60kph). Actually quite close to the normal breakdown in the tests. Another interesting thing is my average range is *exactly* the quoted value (233km). This is my average over 2 years, always in sports mode, always defending the honour of MINIs everywhere at traffic lights, *but* adhering to the speed limit by using the speed limiter function (very useful for your license).

Anyway, the point is that the Tesla probably is very close to 28kWh/100mi, but the MINI is nowhere near 31 kWh/100mi - more like 20. It actually is a *very* efficient EV, mainly due to the size and weight.

 

Not an AWD Ioniq 5. But our heavier, larger, Kia e-Niro regularly matches or surpasses the SE in efficiency on similar days. This is on OE SE 16 Hankooks. A little surprised at first, but the Niro platform was created with efficiency in mind over the sportier MINI Cooper platform.

Sent from my ONEPLUS A6003 using Tapatalk

 

Weight has almost nothing to do with efficiency (except during very frequent stop/starts) and physical size ≠ aerodynamic size (can be quite deceiving!)

Not sure what the SEs drag coefficient is but with the steep windshield and boxy shape I don't think it's that great

 

Is there an SI measurement unit for BEV consumption? The de facto standard in Europe seems to be kWh/100km — easy to slide into, considering the standardized l/100km for fuel consumption. But I don’t think it’s an SI unit yet. The EPA window labels in the US are laughably ambiguous and confusing, with MPGe, kWh/100mi, and “annual cost” based on some arbitrary “national average electricity cost.”

 

All of this sounds like ICE apologists looking for excuses to minimize benefits of EVs. Does anyone factor out the gasoline used to drive to fuel stations to fill up when calculating ICE mileage? Seems similar to me to the wall loss when charging.

 

Probably kWh/100km for SI but only for the metric system users. Using mi/kWh makes it much easier for adjusted GoM estimations.

I believe the Ioniq 5 coefficient of drag is 0.288 and a typical mini cooper should be about 0.3 (pre-2022 air curtains). The Mini has a frontal area of about 21.3 sq. ft so the Ioniq 5 would need to 22.1875 sq ft to be equivalent in CdA. Guess the rear wiper delete is worth the efficiency because nobody uses a rear view mirror these days.

 

Actuallly, weight does have an impact. The three main loads on any car (EV or ICE) are rolling resistance, air friction, and accessory load (hotel load). Rolling resistance is proportional to weight and the type of wheel (ie tyre). air friction is proportional to the drag coefficient, the frontal area, and the density of air ('which changes with temperature and pressure). Accessory load is everything the car is using that doesn't propel it, eg. air conditioning, battery cooling/heating, power electronics etc.

At slow (city) speeds, air friction is minimal, as it depends on v squared (speed * speed). Double your speed = 4 times the drag. Rolling resistance doesn't depend on speed. You also need to haul the weight of the car around, going up hills uses energy proportional to the weight of the car. Going down regens a percentage of the energy used going uphill, but not all of it. At freeway speeds, air friction is the dominant loss as it quickly increases with speed.

As well as the physical losses, there is also the efficiency of the drive train. You may need x kW of power to travel at y km/h, but if the motor/electronics is only 50% efficient, you need to supply 2 * x to deliver x at the wheels. It means efficiency is quite complicated, but to boil it down:

(assuming the rest of the car is kept constant)
* a light weight car will be more efficient than a heavy one
* a smaller (area) car will be more efficient than a larger one
* a sleeker car will be more efficient than a less sleek one
* better electronics is more efficient than not so good electronics

So a small, light, sleek car with good electronic efficiency is the holy grail - check out the Aptera. Appologies for the size of the post - it grew from what I intended

 

Wheel of Fortune says "long-lasting charge." Maybe we'll have a new forum member from USC.

 

I did say almost haha but you're right it's not nothing.

Assuming this generic 0.015 coefficient of rolling resistance, the 1000lb! difference between the SE and Ioniq 5 would add 15lbf of rolling resistance. For comparison, the SE's aero drag at 70mph is 78lbf (based on the numbers posted above).

The 1000lb weight increase would affect efficiency about as much as road surface, tire compound, or a ~0.5° slope.