Does Audi e-Tron Really Only Use 83 Out Of Its 95-kWh Battery Pack?

FEB 14 2019 BY GEORGE BOWER 74

If true, this goes a long way to explaining why the Audi e-tron’s range seems so low.

So far, we only have two sources claiming this rather large buffer Audi may have built into the Audi e-tron battery- Car and Driver (ref) and a Bjørn Nyland’s winter range test (ref @10:06).

Here’s a quote from the Car and Driver article:

What gives? For one, Audi uses just 81.0 kWh of the e-tron’s 95.0-kWh capacity. Every automaker leaves a buffer to protect the longevity of the pack, but Audi appears characteristically conservative here.

Unfortunately, Car and Driver does not quote a source for this 81-kWh usable energy they are citing.

In Bjørn Nyland’s video, he calculates the amount of energy available at only 82.5 kWh’s. Maybe the battery was cold? We don’t know as we don’t have battery temps displayed during his test, but the outside temps were just below the freezing mark. On the other hand, we would assume that Audi would heat the battery so maybe battery temp doesn’t explain it.

Remember, the e-tron is sporting some pretty high power charge rates. They are claiming 150-kWh charging power good all the way to 80%. What impact does the increased charging have on battery cycle life? Adding buffer is an age-old way to compensate when you are coming short on cycle life. The Chevrolet Volt is a great example.

Could these high power charging rates explain why Audi has put such a high buffer in the battery?

Perhaps, but there are other things that could cause Audi to use such a large buffer, such as poor efficiency of the vehicle itself. It’s heavy, has a poor Cd, and its drive efficiency may not be as good as the Tesla Model X.

Poor efficiency=less range= more cycles on the battery.

We used our performance model to sort out the effect of Audi’s high weight, higher drag and lower motor efficiency compared to Model X. In that study we started with a model of Tesla model X. We then made changes to the model based on what we know about Audi e tron:

We docked the drive line efficiency from .87 to .85

We increased the vehicle curb weight from 5621 lbs. to 5844 lbs. for the Audi (includes driver).

We increased the Aerodynamic Cd from .24 to .29 and accounted for a slightly smaller area in the Audi (6% lower area in the Audi). This resulted in a CDA for the Audi=7.62 ft2 compared to 6.72 ft2 in model X.

The lower drivetrain efficiency, higher weight and increased CDA of the Audi resulted in a range decrease from 287 miles for the Model X (@ 65 MPH constant highway speed) to 260 miles range for the Audi. …a 10 % penalty associated for all the things Audi did that reduce the e-tron’s efficiency. This 10% less range also increases battery cycles by 10%.

We then dropped the usable kWh’s from 98.4 for the Tesla Model X to 83 kWh’s for the Audi e-tron. This dropped the range from 260 miles to 219 miles (another 16%).

The range at 65 MPH should be close to the EPA rated range. So we are estimating that, if Audi really did put in all the extra buffer, the EPA range MIGHT be as low as 219 miles when we get the final EPA results.

Could Audi’s promises of 150 kW charging all the way to 80% be the major culprit?

Is the e-tron really only using 83 kWh’s out of its 95-kWh battery?

We don’t know for sure, and we are anxiously waiting for something from Audi on the matter.

What do you think? Let us know in the comment section.

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74 Comments on "Does Audi e-Tron Really Only Use 83 Out Of Its 95-kWh Battery Pack?"

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If the buffer is that big, they could prevent full charge and discharge. This may increase cycle life by a factor of 10! Sure you may have more charge cycles, but you gain cycles and the illusion that your pack charges to 80% way faster than the competitors.

Possibly it speaks of them not being confident of the battery’s longevity.

If the battery has issues with losing range, then doing this would (a) mitigate the problem by preventing the full charge that causes it, and (b) mask the problem from owners by preventing the vehicle’s usable range from dropping even as the battery deteriorates.

BTW, Tesla just software limited the battery in the X and S dropping the range by 7% or so which should have similar effects (and charging rate benefits near “full” charge) to Audi’s software limited battery. The best part is that Tesla lowered the price of the X and S by $8k when they did this (you can pay $8k more to get the range back but at about $320 per mile (+/- $1000 per kWh) that seems rather foolish).

Software limited batteries, ESPECIALLY if they compensate for battery degradation over time, seem like a great idea to me. A vehicle loosing range as it gets used IS fairly lame after all.

This software limited Model S & X is such a good deal, I would think 90% of new orders will opt for this version. Future comparisons vs I-Pace, e-Tron and Taycan should be price compared to this version of Models S & X.

Remember what Musk said about LION batteries being a compromise of capacity, charge speed, and lifespan? And your final result is a pick of somewhere of those stats.

What Audi is doing is allowing faster charging at the price of lifespan. But by using a large capacity, they make up for the lifespan loss.

That’s actually a reasonable scenario, thanks! Some of the suggestions in the article — such as the idea that extra buffer may be compensation for poor energy efficiency — simply don’t make sense at all. Extra buffer capacity won’t help at all with poor efficiency in the motor, the inverter, or the EV powertrain as a whole.

Cycle life doesn’t seem to be good as well.
E tron battery warranty is 100k miles, Tesla S/X infinite miles.

Lies. Tesla batteries are 100k miles warranty as well

Wrong. Tesla Model 3 LR (80 kwh pack) warranty is 120k miles

Model S and X 85kWh and up are 8 yrs unlimited miles.

Not sure I buy into the premise, that using 85% of the battery (81/95) is really that conservative. Tesla is just north of 90%. Volt (@10.2/16) began and an especially conservative ~64%. We used to do these calculations on all the plug-ins and found OEM frequently limiting to ~80%. Of course, with an engine on board it makes no sense to compromise cycle life. Conversely, If I remember, Mercedes B-Class all-EV’s range charge broke just over 90%.

“If the buffer is that big, they could prevent full charge and discharge. This may increase cycle life by a factor of 10!”

Well, every EV maker puts a buffer into the battery charging system, to prevent charging to 100% of the battery cell manufacturer’s nameplate rating/ voltage, and to prevent discharging to 0%, both of which lead to premature battery aging. For example, I’ve seen a claim that Tesla uses a 4-8% buffer, depending on which battery pack size.

But assuming the norm for BEVs is a 5%-10% buffer, then why would increasing the buffer size to 15% increase cycle life by a factor of 10? That seems rather unlikely.

Without that buffer, the range of e-tron would be same as Tesla X100D. Interesting.

No, this article does not say that at all. It is at least 10% lower even before you account for the 5kWh smaller battery.

How in the world did you arrive to that conclusion? So you think they put the buffer in to strictly make them look worse??

The Audi e-tron quattro will be a very popular EV model in Europe.

That’s called brand loyalty. Or at least Euro-centric loyalty. Nothing wrong with that, but WW sales will tell the true story of whether this is a successful vehicle.

Alternatively the Tesla support in the US is US centric loyalty?

Alternatively again Europeans don’t necessarily need to drive the same distances, and ignoring range there’s no compelling reason to go for one over the other – you hit personal preference for things like drive, interior and exterior style, and ease of getting somewhere to buy/repair it.

“Alternatively the Tesla support in the US is US centric loyalty?”

Some of it is, yes. Otherwise there would be no reason for all the arguments over whether or not Tesla cars are “the most made in the USA” or not.

This is certainly not unique to Americans. Germans also seem to heavily favor cars made in their own country. Nothing wrong with national pride, so long as it’s not inflated so far that it becomes xenophobia and bigotry.

E-Tron’s performance is lower than the TMX, but so is its price, starting at $13,000 less than the 100D in the US. I’d have to check the options to make them equivalent, but that does include a small tariff and shipping fees for selling in the US.

Going the opposite way, TMX has a 10% tariff in Europe + shipping fees. So expect TMX to cost over $13k more in Europe vs the e-tron. I’m sure there’s prices listed somewhere already, but I don’t have time to look them up right now.

In Germany the E-Tron starts at €79,900, the Model X starts at €115,980, so €35k (~$40k USD) more than the E-Tron. That’s a big difference in price.

For comparison, the Model 3 starts at just under €60,000.

In Germany nobody ever ordered a base-price high level Audi. Nobody ever.

And how many people have bought a base model Tesla?

The point remains. You CAN buy one or the other for those prices. There’s a significant difference in purchase price between the two vehicles.

And if you do upgrade the E-Tron you’re going to struggle going over €90,000, which still leaves a significant difference in price.

There are other reasons as well. This car is supposed to be sold to people that don’t actually care about EVs. They wouldn’t be very happy to run out of juice while the car did predict that there is capacity left.

Not stocked at dealerships. you have know about this car to get one.
So, the buyer will know it’s an EV.

There are vehicles for test drives at dealerships. Anyhow, the stocked car sales model is a North American quirk.

Funny thing, I got a downvote on my initial comment. I can only assume that comes from someone who knows that it is an issue with a rather common EV.

This complaint is also a weird one considering Teslas aren’t stocked at “dealers”, and even in North America most EV’s need ordering.

It’s a function of supply/demand as much as anything else.

It’s certainly a function of very low supply. In other words, it’s a mere compliance car, not intended to be sold in large numbers, at least not in the U.S.

And how odd to try to use Tesla as a counter-example here. Stocking dealer lots with cars is Audi’s business model, but certainly not Tesla’s. You must know that, so why cite that as a counter-example?

“A foolish consistency is the hobgoblin of little minds.”

It’s a business model of most manufacturers in the North America yes (but not elsewhere), yet most other manufacturers EV’s are also order only.

As for Tesla, they would (and occasionally have when supply is enough) have vehicles available to drive off the “lot”. When supply and demand level out it’s likely that will become more prevalent.

Your attempted Jedi mind trick has failed. (The Force is weak in this one!)

If Audi stocks its dealer lots with other cars but not the e-Tron, then it’s because audi doesn’t expect to sell many — at least not in the USA.

This isn’t merely evidience, but absolute proof that Audi regards the e-Tron as a mere compliance car, at least for U.S. sales.

If Audi are producing 30-50k next year, there’s no reason they should “waste” models by having them sat in dealerships.

There are plenty of other vehicles that have this problem, which is why dealers are often limited by how many they can buy. With in demand vehicles with relatively low volumes many dealers can and do buy more than they need, so they can sell them above MSRP. It’s even more relevant when it’s worldwide sales. That car sat on the lot in the US could have been built for a customer in Norway, or Germany instead.

Realistically it’s just VAG trolling. If it was anti Tesla you guys would be “shorters”.

Actually they change their policy because they call out on it

No, it was poor reporting at the time from a single quote.

No it’s sold to people in thier brand

Rather have fast charge all the way to 80% with no buffering and conservative buffer to prevent battery degradation instead of waiting at a chargers for hours on a long road trip

Smaller battery = more stops.
But, yes the advantage of the large buffer is you get a faster charge to 80%.

But that 80% is less than it would be if Audi opened up the full capacity. If you could use 95kWh, then it would still charge just as fast to 80% of 83kWh. This is a case where what looks better on paper is actually much worse in practice.

You have to weigh the PR/perception side of things. Do Audi take some flack for a vehicle with a lower range to start with, or do they try and deal with disgruntled customers in 3 years time when their range has dropped say 10%?

There’s also the option in future to open up the battery capacity if degradation is less than anticipated.

They have to deal with disgruntled customers starting from the first week, because the range is inferior.

Btw. Audi has not delivered one single E-Tron to a private person, not one. Still Audi-Fanboys tell us the opposite.

A disgruntled shopper isn’t a customer; it’s someone who becomes someone else’s customer. If someone chooses to buy an e-Tron, then clearly he/she thinks the range is adequate for their needs.

Volt owners were not “disgruntled” at Chevy putting a large buffer into the Volt battery pack; it’s just what the car came with.

There seems to be an unstated premise here that if Audi is designing its EV battery packs differently than Tesla is, then it’s doing it “wrong”.

No, Audi is — if this article is correct — doing it differently. Tesla doesn’t necessarily have the best approach for everything, and I think it’s going to be interesting to see how this plays out in the market over the coming years, if e-Trons lose battery pack capacity significantly faster than Tesla cars do.

The range will be clearly labelled. That’s completely different to degradation.

Perhaps why the Model 3 SR hasn’t been released yet. All those disgruntled customers complaining about the inferior range…?

We are talking about different things. You are talking about battery degradation, I am talking about charging rates.

You are right. However the perception comment is still true. Perception doesn’t mean it’s really better, just that it seems to be, especially if you’re buying a car with x range. Most people are unlikely to care about battery size – hence why Tesla are moving away from that too.

Maybe it’s just a marketing thing. Maybe Audi wants to be able to say “Our EV charges faster than Tesla cars! …while accepting faster battery pack aging by using faster charging than Tesla allows in its cars.

I don’t think this is either a bad thing or being dishonest. The EV market is new; it’s good that different auto makers are taking different approaches to making better BEVs. Eventually the market will sort out what works the best and what consumers prefer. That’s part of competition.

Alexander Bloch (Auto, Motor & Sport) also said it one of his videos, roughly 80 kwh as per the Audi engineers he talked to.

I usually like the look of Audis, but this one looks frumpy to me. Like a Hyundai trying to look like a Jeep, or something. Too conservative, not sleek enough.

“all the things Audi did to reduce the e-tron’s efficiency”

Really? Come on now, this is poor wording. Your bias is showing.

Audi did not do anything with the intent of reducing efficiency. They made choices which have the effect of lowering efficiency. Frankly, the Model X is ugly. The e-tron is a handsome looking car. That alone means a lot to Audi’s customers. Then there is the utility of a square shape rather than a boat-tail rear end.

You’re right. It should have been worded: “all the things Audi did THAT REDUCED the e-tron’s efficiency”
However, that also implies that the people at Audi who made these decisions didn’t understand the full effects on efficiency of their choices. It is a new field for Audi (and Jaguar and Mercedes-Benz) and they will learn as they get more experience. I’m sure their second EV designs will be better, just like Tesla’s successive EV designs will also get better and as the technology advances to allow better EV designs. I’m very glad that several major automobile manufacturers have moved towards new EV designs giving the consumer more choices and advancing the state of the art of EVs offered for sale.

The design affects efficiency. They may well have known very well that x design feature will reduce the efficiency (they seem to have a reasonable handle on that considering the camera mirrors), but decided that the specific style/design was more important than the reduction in efficiency.

Audi have a design language, removing all that language and producing something totally different because it’s more aerodynamic may not go down well with Audi customers or the Audi brand in the first place.

It provides a more consistent charging experience for the customer. It’s what more automakers need to start doing with their battery configurations.

Very valid point. It reduces or eliminates the needs to explain the taper.

Friend: How fast does your EV charge?
EV Driver: Well, you see, it depends. If the battery is low it charges up to 120kW, but then it slowly tapers off as the battery fills until about 80%, when it is only charging at 50kW.
Friend: … I’ll just stick with my ICE …

The same is true for setting maximum charge levels. You are basically making the people feel bad whenever they fully charge their EV. They shouldn’t have to think about such things.

Exactly. It’s all about perception. Yes the 80% is the the battery usage but when charging the optics we make it’s seem that you are charging in less time then a sub premium ev

But, that 80% buffer means they’ll be pulling in to charge at 60% with a 20% buffer in their head. Meaning More Charging.

Depends on the person buying it. The first adopter may well still be considering eeking out the maximum life from their battery and only charging to 80%. The mainstream buyer is far more likely to just plug in and leave it.

No, it does not depend, it means more charging.

Arguing with yourself? That’s rarely a good sign… 😉

Would you go on a long distance trip in an EV that has a range of 200 miles between charges? No, they will take their ICE vehicle for long trips. Which is why Tesla targeted 300 miles range for the Model 3. I can testify from real world experience that it works very well for long distance trips.

So presumably Tesla should not sell it’s SR and MR versions then?

And all the other manufacturers with vehicles in the 220-260 range are also doing it wrong?

95kWh gross
-8% at the lower end
-4% on top
= 83 kWh net

probably MEB from Volkswagen will do the same
48kWh-12%=43kWh

I wouldn’t be very surprised if they are being very conservative with the battery – they don’t know what to expect and they don’t want to lose a tone of money with warranty costs.
That or they are using one of those cheap (fake) Chinese cells that announce 8000mAh but are indeed 600mAh :).

“I wouldn’t be very surprised if they are being very conservative with the battery – they don’t know what to expect and they don’t want to lose a tone of money with warranty costs.”

A valid argument!!!!

Possible! They don’t want another lawsuit.

Actually if you go on the Audi.de website and configure an E-Tron, you will see in the specs, exactly 83.6Kwh usable.

afaik Audi are using NMC whereas Tesla use NCA batteries. Whilst exact formulation dependent, NMC is typically capable of supporting higher charge rates than NCA however high charge rates typcially introduce degradation. Audi may well have felt it necessary to chose fast charge rates at the expense of degration in order to “better” Tesla in one aspect of EV design; and one way to mask this is to have a large buffer initially that is reduced over time so the degration does not appear as bad. So perhaps 10KWH of degradation over time might be compensated by reducing the buffer by 5KWH making it appear that there is only 5KWH reductioon of usable capacity. This might seem a little odd, but increasingly it apears that actually Tesla covered the vast majortiy of EV design really very well, hence 6 years later major manufacturers are struggling to better Tesla’s fundamental EV design and are parhaps having to resort to imaginative ways to beat them. Fast charging is an easy win, but high degradation would be a killer for resale values and this would quickly bite back to new sales. So Audi have an early “win” for charge rate, but there remains… Read more »

I suspect that Audi provisioned a large buffer for three reasons.
1. The extra buffer at the top of the battery will make the fast charging performance appear better than competitors like Tesla.
2. They can maintain the usable energy available to the driver over the full period of the warranty. It makes it look like zero degradation. However, it will be visible as the car ages with the fast charging slowing down more as it gets full because the true SOC will be higher.
3. When the battery is cold it is susceptible to errors in estimating the energy remaining at low SOC. By having more of a buffer at low SOC, the car will not randomly shut down with range still showing as available.

Or you could just wait until EPA estimated range gets finalized.

one simple explanation could be that they rather prefer to minimize the risk of having to replace a relative high number of batteries under warranty with consequent loss of profits

loss of profits? they will never make any profit with the e-tron.

Very probably correct. Auto makers don’t make a profit on compliance cars, or even try to design them for lowest unit cost and thus good profit margin. For low volume models such as compliance cars, auto makers aim to minimize development costs at the expense of higher unit costs.

“They are claiming 150-kWh charging power good all the way to 80%. ”

kW, not kWh.

I imagine that’s just a typo. Given all his articles about EV engineering, I’m sure George Bower knows the difference between power and energy!

It’s ridiculous that a SUV with a cd of .27 (with camera mirrors) is considered inefficient now. The E Tron is a lot more efficient than it’s given credit for.