So when it comes to reselling...

So when it comes to reselling...

Seems like a big point of selling would be the state of the battery. Ie, is it holding 99% of the original charge, or 90% or what? So, how does one measure and/or express that value?

shawns | August 24, 2013

I wonder if that will be an issue as long as the car is under the battery warranty period? I also am what degradation level will Tesla replace the battery under warranty? 10%, 20%, 30%? Or only on complete failure?

TommyBoy | August 24, 2013

Less than 70% of original charge remaining and they will replace.

I would imagine that before selling a Tesla you would need to advertise using maximum standard charge and range charge numbers.

So if you have a 3 year old Model S you could say:

Maximum Standard Charge - 227 miles
Maximum Range Charge - 257 miles

Oddly it's really an arbitrary number but there really isn't another way to compare all vehicles since they're all driven differently and their batteries become less efficient differently.

cloroxbb | August 24, 2013

I would imagine you would actually measure the Kilowatt hours that the Tesla will take in when charging, instead of relying on the miles algorithm. If the Model S is down to 90% battery capacity, then it would only take 77kwh for a "full" battery...

SCOOBY | August 24, 2013

I think you are right we need a reliable measure of battery health. I'm not convinced the rated range reading at max charge is a particularly good indicator of battery health. Perhaps Tesls will introduce a battery health indicator in a future software release. Or perhaps testing shops will appear who will measure and certify energy delivered from a full charge to empty.

Brian H | August 24, 2013

Over 8 or 10 yrs, my guess is 30%, because the engineers privately only expect about 10%!

stimeygee | August 25, 2013

Is there a way to directly look at the KWH capacity? As far as I know there isn't. So it seems that so far the best measure is "rated range" at a full charge. However - are we sure even THAT represents the actual health of the battery? Ie, when the battery holds less charge as it ages, does it indeed show a lower top "rated range" when charged? Ive seen people here assume that, but based on what? I could imagine that they might have programmed it to calculate the rated range based on the fact that its 100% charged or 90% or whatever, without actually telling you what current capacity that represents.

gooshjkc | August 25, 2013

I think for many Model S owners unless other manufacturers jump on the bang wagon and start making 100% electric cars, they would choose to trade it in for another Tesla.

stimeygee | August 25, 2013

Maybe. But still, there will be some cars sold as used, by private owners.

stimeygee | August 25, 2013

Personlly I think it will be an exciting time when used Teslas really hit the market, opening up ownership at a lower price point.

jat | August 25, 2013

Ultimately, I think used EVs are going to be sold like airplanes -- ie, the age isn't the important part, but rather how many hours of operation and what maintenance has been done. I don't know that we have the information that you need to properly determine the state of the battery, but once Tesla starts offering battery swaps and upgrading your battery, they are going to have to have a way to determine the battery "score" so they can charge your for the delta.

chrisdl | August 25, 2013

Bang wagon... Hehe ;-) (Sorry, couldn't help it. Very funny.)

unclegeek | August 25, 2013

@TommyBoy Did you find that in writing anywhere? (70% figure). I've asked my inside sales rep about this before and she said flat out that Tesla makes NO claim as to capacity retention guarantee over the warranty period.

lolachampcar | August 25, 2013

I agree to a point but planes hold value better due to the lack of new production. I think Tesla is going to pump these puppies out which may depress the secondary market a small amount. On the other hand, every time they have raised the retail they have increased the value of my used car. I could not have sold the P85 and gotten the + for what I did without those price increases :)

Vicelike | August 25, 2013

I would assume that Tesla will make new innovations in batteries available to current owners at a price.

So rather than buy a new Tesla and sell your old one, just trade in your old battery for a new one giving your car less weight, more range and better performance.

They can afford to sell the car frame and electronics at cost and make all their money on battery upgrades / replacements.

Sort of like Gillette.

If I could do that, I would tend to hold on to my 2013 for as long as it looked as nice as it does now.

This would impact supply and demand for the used cars in a most beneficial way as it would limit supply and support higher prices for the newer and older models.....

Just speculation on my part but it fits Elon's concept for getting a mass market for his cars.

stimeygee | August 25, 2013

Back to my OP -

So is "range" the only indicator of the state of the battery? And are we sure it does even that (as per my previous post)?

Brian H | August 25, 2013

It's really the same thing, just expressed in miles rather than kWh.

jat | August 25, 2013

@BrianH - The question is does the current charge capacity of the battery encode all the history of its aging, or could two batteries with the same current capacity have different later capacity slopes because of how they were used earlier.

mdemetri | August 25, 2013


Currently, the best indicator for the state of the battery would be 'ideal range' rather than 'rated range'. There have been many threads questioning the meaning of 'rated range' and whether or not it may be impacted by driving style (eg see posts by Tikiman). While this remains a controversy, 'ideal range' is most certainly not impacted by driving style and therefore should be the best gauge of battery health over time. Of course, tesla providing us with a direct measure of kwh capacity would be much better.

Fred O | August 25, 2013

@unclegeek I checked the limited guarantee document that Tesla put on the MyTesla page. No percentage is mentioned. I'm in Europe and thought there may be a difference between the States vs Europe. It is probably at the discretion of Tesla but I have not asked a DS yet.

Brian H | August 25, 2013

What present-time diagnostic could reveal that?

Jolanda | August 26, 2013

The battery pack seems to have a build in meter for battery quality. Tesla is able to read this, so when you want to sell the car you go to the dealer and ask him for a printout.

Zero EV | August 26, 2013

If Tesla starts offering battery swap at the Tesla Stations (Superchargers), doesn't this become a moot point? You'll be able to swap out your battery for ~$60 (about the price of a 15-gallon fill-up, according to Mr. Musk)

@stimeygee - I think you can switch from "Miles" to "kWH" for your battery capacity display ... I think it's in the Driving settings.

eAdopter | August 26, 2013

TM has documented a few facts we can currently verify.
(contact their legal department for documentation)

New batteries will cost $10k-$12k, for 60/85 kWh respectively.
New batteries will have a 1-year warranty.

An Extended Battery Warranty will be available.
Warranties range in length from one to three years
Costs range up to $7500 for the 3-year warranty
(I don't recall prices for the 1-year and 2-year warranties, but remember they're not cheap)

I wonder how many people will:
1. pay $10k-$12k for a new battery with only a 1-year warranty?
2. be willing to purchase an extended battery warranty at those prices?

My first battery was replaced after only three weeks. For me, the option to purchase a new $10k/$12k battery with such a short warranty will be a deal killer. I would want another 8-year/100k warranty.

I also don't think a 3-year extended battery warranty is a good value for $7500.

What do others think? Maybe it comes down to how much people love/want their cars when the current warranties expire?

Brian H | August 27, 2013

the $60 is for the electricity only, and assumes you come back for your own battery. If you opt to keep the swap, you pay for the upgrade in capacity, if any. Nobuddy nose what that cost will be.

J.T. | August 27, 2013

@BH That stinks.