Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Question about buying a used Tesla with a bad Li-ion battery

Maryland

Member
Jul 30, 2020
56
56
Maryland
Hi all,

I am currently looking at a 2015 Tesla Model S P90DL. Vehicle has ~37,500 miles. Title is clean. It is being sold by a Mercedes dealership, not a Tesla dealer.

When the dealership received the car as a trade-in, the car ran great. However, the dealership let the car sit for about a month without being charged. The li-ion battery was completely empty for at least 3 weeks. I assume the 12v battery is also either dead or in poor health.

After prolonged neglect, they finally charged the vehicle. However, now it will not charge past 16% capacity. Additionally, the LCD display does not power on (I assume because the 12v battery is dead...?).

They named a price to sell the car as-is, and even despite these red flags, I am still interested because it's about $10k under market value. However, it's only a really good price *IF* it can be fixed under warranty. The battery is still covered under warranty, and being unable to charge past 16% would certainly qualify for replacement. At least that's my thinking. However, I read that "abuse and neglect (including ignoring service notifications) can void this warranty." So I have to question if Tesla might be able to know through a diagnostic scan that the car was left uncharged for a long period of time and then judge this to be neglect, voiding the warranty.

In addition to all of this, I must also consider what would happen if the car was not fixed even after a battery replacement. Or, alternately, if the battery is fine and it's something else that's broken (Charger?). As long as any repairs total at/under $5k, I'd still be getting a good deal.

So I guess best-case scenario: I'm getting a car with a brand new Li-ion battery at a really, really great price. Worst-case scenario: I'm getting a car that needs a Li-Ion battery, and I'm going to lose a lot of money.

If money was no object, I would just buy a different vehicle, but I've got a budget, and if I can buy a $55k car for $45k, then that's really important to me. Plus, this model checks all of the boxes for everything I want—it's basically a dream car for me, and it's actually in my price range. I guess I just want to hear the community's opinion on whether or not this car is worth the gamble.

Questions:
  1. How safe is it for me to assume that replacing the battery will fix the issue?
  2. Do you think Tesla would cover the battery under warranty even despite the prolonged neglect? Would they even know that it sat forever? And is 3 weeks even really long enough to count as neglect?
  3. How much would it cost out-of-pocket to replace the li-ion battery (parts + labor)?
  4. Can I talk to Tesla and get a ruling on the battery being covered under warranty before buying the vehicle? (I doubt it because I'm not the owner and they're difficult to contact, it seems).
  5. How possible is it that there's something else wrong and the battery is not the issue?
Thanks for reading. There's a lot of useful information on this forum and a lot of knowledgeable users, so I figured this would be the place to ask.
 

serendipitous

Member
Sep 10, 2019
419
695
Maryland, USA
Tough to say without fixing the 12v battery first and addressing the other issues. Could be as simple as a 12v battery replacement and everything just starts working again. How do you know it's charged to 16% if the screens aren't turning on? Is the instrument cluster working but not the center screen? In that case I'd be nervous about MCU failure (not under warranty since it's >4 years) so that's $2500 to upgrade to an MCU2 or ~1500 to replace with another MCU1. Either way you should budget for that since it will happen at some point.
 

ucmndd

Well-Known Member
Mar 10, 2016
7,323
14,309
California
"The LCD display doesn't power on" leads me to believe that your actual problem is a MCU failure and not a bad battery.

Cars with dead MCUs have all sorts of weird issues, sometimes including the inability to charge past a fairly low level.

It's hard to tell from your post, but it sounds like the rest of the car's 12v systems are working and you're determining the state of charge from the instrument cluster, able to open the doors, etc. Does the car actually drive? If that's the case, then again, sounds like the MCU is the problem.

They're about $1800 to replace with the "old" version currently in the car, or $2500 to upgrade to the "new" MCU2 that has been present on Model S since early 2018.
 

David.85D

Active Member
Oct 29, 2016
1,515
1,290
USA
Just to stir the pot, who says that car is worth $55k in working condition?

you can buy a well optioned P90DL with 49k miles and two year warranty from Tesla for $54.4k. Dealer car with no warranty maybe $50k? 45k? Then the uncertainty of the bad batteries, MCU, etc puts you more like $30k if you’re willing to risk having to buy the new battery and MCU.
 

Maryland

Member
Jul 30, 2020
56
56
Maryland
I suppose I just needed to be talked out of a bad decision lol.

Tough to say without fixing the 12v battery first and addressing the other issues. Could be as simple as a 12v battery replacement and everything just starts working again. How do you know it's charged to 16% if the screens aren't turning on? Is the instrument cluster working but not the center screen? In that case I'd be nervous about MCU failure (not under warranty since it's >4 years) so that's $2500 to upgrade to an MCU2 or ~1500 to replace with another MCU1. Either way you should budget for that since it will happen at some point.
Honestly I'm just going by what the dealer is saying. Didn't occur to me it could be MCU failure.

"The LCD display doesn't power on" leads me to believe that your actual problem is a MCU failure and not a bad battery.

Cars with dead MCUs have all sorts of weird issues, sometimes including the inability to charge past a fairly low level.

It's hard to tell from your post, but it sounds like the rest of the car's 12v systems are working and you're determining the state of charge from the instrument cluster, able to open the doors, etc. Does the car actually drive? If that's the case, then again, sounds like the MCU is the problem.

They're about $1800 to replace with the "old" version currently in the car, or $2500 to upgrade to the "new" MCU2 that has been present on Model S since early 2018.
The car does drive, and the doors do unlock. Maybe it is the MCU like you're saying.

It does seem weird that sitting for 3+ weeks uncharged would make it unable to charge past 16%.

But also weird the MCU would die just for sitting unpowered.

Just to stir the pot, who says that car is worth $55k in working condition?

you can buy a well optioned P90DL with 49k miles and two year warranty from Tesla for $54.4k. Dealer car with no warranty maybe $50k? 45k? Then the uncertainty of the bad batteries, MCU, etc puts you more like $30k if you’re willing to risk having to buy the new battery and MCU.
Yeah, maybe I am overvaluing it a bit. I guess the thought of it having a new li-ion battery upped it a bit in my mind. Also I might be overvaluing the difference between 37500 miles and 4x,xxx miles. I mean the warranty is expired either way, and we're only talking about a dozen charge cycles added to the vehicle, if that.
 

PWlakewood

Active Member
Jan 9, 2019
1,800
1,122
US
The Mercedes dealer won’t know anything about Teslas. I’d go look at the car, play up how they’ve damaged it (bad MCU and batteries) then offer them $30k.
Id go lower. 25k. Its not just the expenses for replacement parts its also the added risk and headaches that you will get dealing with tesla service. I would have them throw in a bottle of excedrin migraine just to be ready.
 
  • Like
Reactions: maximizese

domodan

Member
Jul 15, 2020
436
202
UT, United States
Id go lower. 25k. Its not just the expenses for replacement parts its also the added risk and headaches that you will get dealing with tesla service. I would have them throw in a bottle of excedrin migraine just to be ready.

You guys are out of control. $25k. The dealer might not know a ton about Teslas but they’re not idiots. They see these cars on a regular basis. They’ll recondition the car before taking a massive loss, and they’d get more than that at auction. Wrecked cars with salvage titles (still wrecked) bring more than that.
 
  • Like
Reactions: DCEV

Maryland

Member
Jul 30, 2020
56
56
Maryland
I suppose I'll low-ball them on Monday instead of simply saying I'm not interested lol.

But yeah, 25k is definitely too low. Fact is they could put this car to auction and receive way more, even as a parts car (which it is not).
 

David.85D

Active Member
Oct 29, 2016
1,515
1,290
USA
What does an otherwise operable Model S sell for without a battery? That would help set a value (minus risk premium, set aside for unknowns, value of time, 2.5k for MCU, etc). I don’t recall seeing one for sale. The used packs sell for $16k to $20k on eBay.

I’m someone that has bought a used BMW with the engine in a box in the trunk. It was worth the price I paid. It’s always worse than you hope. I also look for a price that rewards me for the risk and some padding for unknown issues.

But I don’t believe for a second when a dealer says something is easily/cheaply fixed. If it was, they would have! It’s likely they already tried and either made it worse or got a crazy high estimate.
 
  • Like
Reactions: whitex

PWlakewood

Active Member
Jan 9, 2019
1,800
1,122
US
You guys are out of control. $25k. The dealer might not know a ton about Teslas but they’re not idiots. They see these cars on a regular basis. They’ll recondition the car before taking a massive loss, and they’d get more than that at auction. Wrecked cars with salvage titles (still wrecked) bring more than that.
Have you checked how much tesla wants for a replacement battery lately.....i will wait



....anyways...if you purchase this S as is you might be stuck with a defective battery and if tesla determines negligence on the part of whoever then the new owner is stuck with full replacement cost of the battery.
 

PWlakewood

Active Member
Jan 9, 2019
1,800
1,122
US
I suppose I'll low-ball them on Monday instead of simply saying I'm not interested lol.

But yeah, 25k is definitely too low. Fact is they could put this car to auction and receive way more, even as a parts car (which it is not).
How do you figure. First off the selling price is too high second a model s battery can cost 20k so 25k is a good price if you are stuck with the cost of a replacement battery. Good luck either way and keep us posted on outcome.
 

domodan

Member
Jul 15, 2020
436
202
UT, United States
Have you checked how much tesla wants for a replacement battery lately.....i will wait



....anyways...if you purchase this S as is you might be stuck with a defective battery and if tesla determines negligence on the part of whoever then the new owner is stuck with full replacement cost of the battery.
Obviously you get it checked out before you buy it.
 

domodan

Member
Jul 15, 2020
436
202
UT, United States
How do you figure. First off the selling price is too high second a model s battery can cost 20k so 25k is a good price if you are stuck with the cost of a replacement battery. Good luck either way and keep us posted on outcome.
You think $45k is too much for a loaded 2015 with 37k miles and Ludicrous? That’s a steal here.
 

murphyS90D

Member
Jul 2, 2016
709
509
Horsham, PA
The Li-Ion battery was not completely empty. When it shows zero miles the battery protection charge is still there. It would take way longer than a month for that charge to bleed off because in that situation the car is in deep sleep with everything turned off. The 12 volt battery would be dead.
 

whitex

Well-Known Member
Sep 30, 2015
6,791
8,626
Seattle area, WA
You guys are out of control. $25k. The dealer might not know a ton about Teslas but they’re not idiots. They see these cars on a regular basis. They’ll recondition the car before taking a massive loss, and they’d get more than that at auction. Wrecked cars with salvage titles (still wrecked) bring more than that.
Not necessarily. If it's one of those "cat in a bag" deals, why not? Tesla trade-in value is probably just south of $40K (fully working one with twice the miles with 2 year warranty sells for $46K, so Tesla probably values the trade-in at $36K), which is likely to be an auction price for a fully working car. A non-working condition car out of warranty is always a risk, and fixing Tesla's is not cheap (or fast). Remember, as I understand it "as is" means you have no guarantees whatsoever, so what if the car was flooded for example (all battery warranty is void in such a case)? How much is that risk worth? That of course depends on "worth to whom". If there are actual money back guarantees attached to the car, such as for example "the seller will cover any costs above $5K to return the car to full operational condition", then of course the price should be higher than $25K. But with no guarantees and buying a question mark, there has to be some upside (possibility of coming up ahead) for the buyer who takes all the risk.

Bottom line, we cannot tell if $25K is a good price or not, unless we have more details. If the deal is "non-operational 2015 P90DL, looks intact but no other information", $25K could be a good gamble, but still a gamble.

One good way to take out of of gambling price rage, is take it to Tesla and get a quote how much to fix, then you can negotiate with less risk.
 
Last edited:
  • Like
Reactions: PWlakewood

whitex

Well-Known Member
Sep 30, 2015
6,791
8,626
Seattle area, WA
The Li-Ion battery was not completely empty. When it shows zero miles the battery protection charge is still there. It would take way longer than a month for that charge to bleed off because in that situation the car is in deep sleep with everything turned off. The 12 volt battery would be dead.
12V battery would be dead if the battery went into hibernation mode. Hibernation mode would make the battery survive more than a month. The fact that 12V battery is not dead (doors open according to OP) it could be because the dealer charged it up, or put in a new one, or maybe the main battery was recharged by someone at the dealership.
 

PWlakewood

Active Member
Jan 9, 2019
1,800
1,122
US
You think $45k is too much for a loaded 2015 with 37k miles and Ludicrous? That’s a steal here.
It's obviously been neglected and why didn't the dealership get it checked out? Something could be wrong with it and they are just trying to punt it to someone who will take their word that nothing else is wrong. Can you really trust a dealer that neglects its cars? I know I wouldn't. Its also 5 years old and is still depreciating so if they are selling it for 45k they must only have 35 to 38 k into it.
 
  • Helpful
Reactions: Sergeiest

PWlakewood

Active Member
Jan 9, 2019
1,800
1,122
US
Obviously you get it checked out before you buy it.
How? If the battery has any issues and won't charge enough then it would have to be towed at whos expense? I would have the dealership get it to tesla and have them cover all expenses until the person decides to buy it.
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top