Audi A7 vs Tesla S Comparison

Is the Tesla S a Good Buy?

Some friends of mine have recently been touting the incredible deal that is the Tesla S. At hearing my general skepticism of “leaps” in engineering, and debating for a solid hour during my younger son’s birthday party, they asked me to run a rudimentary cost assessment. Fair enough.

I decided to do this in the form of a comparison. I don’t see the whole EV thing as meaningful unless it offers results. Emissions, after all, don’t have to come from the pipe; and dollar costs, no matter how arrived at, usually have proportionately large resource impacts. After all, an $8,500 incentive substitutes others’ purchases, which aren’t limited to cars.

I like to pretend the Tesla S is a really efficient gas-powered car, with a tiny fuel nozzle; so you can only really trickle the gas in, and only at home because doing this at a gas station would be really really rude. You could also go to special, designated, “super” gas stations, where they have equipment that opens the nozzle more fully, but you have to buy a special nozzle for that… but I digress..

Here is my not-so-back-of-napkin assessment, based on 4-year ownership and re-sale. Why 4 years? Because, let’s face it, someone in the market for Tesla isn’t going to be keeping her for very long. It’s not how much you spend, after all, it’s how much you save.

I’ve decided to run a comparison against an Audi A7; mostly because it’s also a bit of a vanity car, and the price is comparable, but also due to comparable power and acceleration; something prospective Tesla owners seem to value rather highly. I suppose that’s because Priuses are also an option they’ve discounted.

I also don’t really consider insurance costs. I’m not sure what they would be on a Tesla. Speaking of which, I’m also not sure how long that company will exist, but we’ll just assume it’s going to be around for a while.

Genaral assumptions:

  • Ownership term: 4 years
  • Gas [$/L]: 1.30 Assuming current trends
  • Electricity [$/kWh]: 0.09 Assuming current trends
  • KM driven/year: 10,000
  • Charger efficiency: 85%
  • Battery 4-year capacity: 90%
  • Gas 4-yr efficiency: 97%

I’m assuming a smaller than average mileage because a Tesla can’t be used to travel large distances, so it would be excluded from those trips. One could claim this as a benefit, but, really, this just means the Tesla can only be a second (or third) car, with another (gasoline car) serving as the long distance mule.

I’ve also chosen to add leather, bells and whistles because 1) they’re standard with the Audi, and 2) because I can’t think of a single person who’s in the market for a Tesla that wouldn’t buy them. I could have chosen a more expensive Audi to compare to, but the A8 is monstrously powerful, it wouldn’t be fair.


A large determinant of resale is going to be the known unknown that is the battery. I have a laptop, and I use it often. It’s powered by a lithium battery which tends to follow a predictable degradation pattern. It’s ok for the first year, kind of ok for the second, and then I have to replace it because it suddenly ceases to function. I’m going to assume here that Tesla engineers aren’t miracle workers, and that they haven’t invented a new kind of lithium battery that never needs replacing. Instead, I’ll pretend like they have extended the life a little, which is the best I can imagine them doing. They claim 10 years, I’ll give them 8, which is all they’re willing to guarantee anyway — a propos, I think this warranty will sink the company.

With that, there’s the battery replacement cost. Friends and forums tell me that it’s around 12k, maybe 20. That’s a big hit, and I’d expect nobody to buy a used Tesla unless the battery had been recently replaced, or they’re compensated for having to do it sooner. Used car buyers usually care about things like reliability and longevity a lot more than new car buyers. Tesla owners will have a really hard time pawning those things off, especially with no engine to mitigate the risk. I’ve therefore assigned a battery amortization value, rather conservatively, at 5,000 dollars for the four-year ownership period.

I suppose you could quibble with my resale values. But it’s all guesswork now; this is a new car with new technology. History isn’t kind under those circumstances, and there’s no guessing about what will happen to those batteries with time and use. Besides, if that’s the basis of rebuttal, then what are we really considering? Because it’s certainly not EVs.

The Numbers:

Audi A7 Tesla S 85 Tesla S 60 Comments
Seconds 0-60 5.6 5.6 5.9
EPA Range [km] 650 424 335
Fuel Tank [L,KWh] 65 85 60
Consumption [L,kWh/100km] 10 20 18
Cost [$/100km] 13 2.4 2.1
Base Price 74,800 57,400 57,400
Charger + Capacity 0 22,700 12,700
NAV, Cameras, Lights Included 3,750 3,750
Premium Sound 850 950 950 Similar cost, why not.
Leather? Included 1,500 1,500
Not Black or White? 0 750 750 Really, This is extra?
Supercharging 0 0 2,000 All gas cars “supercharge”
Incentives 0 (8,500) (8,500)
Purchase Price 75,650 78,550 70,550
House Electrical 0 3,500 3,500 Can’t see anyone skipping this.
Regular Resale value 37,000 38,418 34,506 Similar depreciation assumed
Battery Value Adjustment 0 (5,000) (5,000)
Adjusted Resale Value 37,000 33,418 29,506
4-Year Totals
Capital Cost 38,650 45,132 41,044
Fuel 5,200 960 840 Not one of the big numbers …
Renovations 0 3,500 3,500
Net 43,850 49,592 45,384
Cost Per Day 30.03 33.97 31.09

Note: Seeing here how much cars actually cost to own, I’m beginning to doubt my own decision-making.

Anyway, the outcome seems to be a bit of a wash. For me, the clincher is below, in the relative convenience.

Read on ..

Qualitative Comparison:

Audi A7 Tesla S 85 Tesla S 60 Comments
Time to fill 5 minutes Variable, 30 minutes to overnight Supercharging seems moot. I can’t see myself scheduling a fill at some specific location. I’d rather go home where the nachos are.
Can take to cottage Yes Probably not, unless you live there
Can take overnight Yes If < 180km If < 130km Otherwise depends if there’s a charger available
Pessimistic Range 650 212 168 Most destinations don’t have a charger, so you have to come back
Convenience Great, charge stations everywhere! Horrible, have to schedule if not charging at home
Reliability Excellent Unknown, new product.
Wintering Reduced mileage in very cold winters Unknown, new product.
Salt + Humidity I haven’t seen anything written on this. It makes me nervous given the layout of the drivetrain. Electrical systems, moisture and salt don’t play nicely together.
Parts Cost Med – High High – Very High


I dunno, I’d rather get the Audi.

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