Battery issues on a used car I'm looking at. Any advice?

[Ashriot]

Hi everyone! I have an interesting quandary. I used to own a 2017 i3 Rex and really enjoyed it. I've decided to get another one, and found a 2019 i3s BEV for a good price. I have already started to move forward on the buying process, but noticed in a photo of the odometer that the battery was about 2/3 full and only showing a range of 73 miles. Reversing the math that's a little over 100 mi total range, which seems very low (since the car is rated for 153).

I know a lot of factors contribute to projected range, but I actually ended up stumbling across the previous owner of the car (who returned it after about 3 months) who said that the range was calculated to be exactly 70% and the dealer said they can't honor the battery warranty until it is less than 70%.

He said he returned the car because while driving on the highway, he accelerated from 65 to 75 when the car reported a drivetrain fault and forced him to pull over and have the car towed. (A scary situation..)

Apparently, the BMW dealer mechanics couldn't reproduce the issue and said it was most likely due to the reduced capacity and that when it drops below 70%, the battery could be replaced for free.

Now I don't know what to do as I've already placed a down payment on the car. Part of me wants to just get out of the deal out of fear, but the other part would be OK accepting it and just trying to get the battery replaced when it inevitably drops below 70%.

Does anyone have experience having their battery replaced under warranty? Does anyone have any other feedback or advice? I know BMW is a solid company, but the car suddenly being disabled on the highway is worrisome.

This car would mostly be for getting around down as we have a second car for longer trips. I could really use some advice. Thanks!

 

[EvanstonI3]

That makes no sense. Also you can't judge battery capacity by looking at the Guess-O-Meter. Never heard of a 2019+ model have battery degradation like this and being replaced. Why don't you look at the BATT.KAPPA.MAX reading in the Hidden Service Menu on the dash and see what it says? That's also a rough guess, but better than relying on what the Range Display says.
Also- where you in the world and how cold is it? Previous owner could have been trying to push the car over the limits of what the battery would allow in very cold weather. That could have produced the "Drivetrain Error".

 

[Ashriot]

That makes no sense. Also you can't judge battery capacity by looking at the Guess-O-Meter. Never heard of a 2019+ model have battery degradation like this and being replaced. Why don't you look at the BATT.KAPPA.MAX reading in the Hidden Service Menu on the dash and see what it says? That's also a rough guess, but better than relying on what the Range Display says.
Also- were you in the world and how cold is it? Previous owner could have been trying to push the car over the limits of what the battery would allow in very cold weather. That could have produced the "Drivetrain Error".

I meant to clarify that the previous owner had it tested at the BMW dealer, he didn’t just guess. The dealer told him it was 70% through their own testing and not eligible to be replaced yet.

It’s in Arizona, which can get cold at night in the winter especially, but not snowy cold. I actually live in Florida so I don’t have direct access to the vehicle.

It is a strange story. I’m just concerned the car is a lemon and don’t want to get stuck with it.

 

[EvanstonI3]

The previous owner had it tested at the BMW dealer, he didn’t just guess. The dealer told him it was 70% through their own testing and not eligible to be replaced yet.

I have seen others who have relied on a Dealer's "testing" and they never actually did the proper test. They just plugged into the diagnostic port and read the battery levels which was useless. Dealers generally do NOT want to do the HV Battery test because it involves a lot of their TIME, plus many don't seem to know how to actually perform it. If you can, ask the previous owner how much he paid for the "test".
Even if the HV battery was degraded to 70%, I don't see how that could cause the "Drivetrain issues" that the previous owner experienced. It just means your range is reduced. You should still be able to go 65-75mph.

 

[Ashriot]

I have seen others who have relied on a Dealer's "testing" and they never actually did the proper test. They just plugged into the diagnostic port and read the battery levels which was useless. Dealers generally do NOT want to do the HV Battery test because it involves a lot of their TIME, plus many don't seem to know how to actually perform it. If you can, ask the previous owner how much he paid for the "test".
Even if the HV battery was degraded to 70%, I don't see how that could cause the "Drivetrain issues" that the previous owner experienced. It just means your range is reduced. You should still be able to go 65-75mph.

I see. I reached back out to him and he said that he just took it to the dealer to determine what caused the drivetrain error and they came back and told him that it was likely due to the battery degradation and that it was currently at 70%. But they said they did their own internal testing and driving and couldn’t reproduce the drivetrain error.
If you don’t think it could be related to the HV battery then it seems like the car might just be faulty, which is worse. Thank you for the insight! I’ll probably pass on this car

 

[EvanstonI3]

I see. I reached back out to him and he said that he just took it to the dealer to determine what caused the drivetrain error and they came back and told him that it was likely due to the battery degradation and that it was currently at 70%. But they said they did their own internal testing and driving and couldn’t reproduce the drivetrain error.
If you don’t think it could be related to the HV battery then it seems like the car might just be faulty, which is worse. Thank you for the insight! I’ll probably pass on this car

If you take the car in for the Test, you pay $250-$800 to the Dealer for that test if the car does not fail. I would think if he paid that only for the car to "Pass" he would have mentioned it.

 

[Ashriot]

If you take the car in for the Test, you pay $250-$800 to the Dealer for that test if the car does not fail. I would think if he paid that only for the car to "Pass" he would have mentioned it.

Do you have any advice about passing on buying the car? Would you be concerned about the range or the drivetrain error forcing him to have to tow the car?
I appreciate your opinion

 

[EvanstonI3]

Do you have any advice about passing on buying the car? Would you be concerned about the range or the drivetrain error forcing him to have to tow the car?
I appreciate your opinion

I think you should pass on this if possible as there are too many unknowns here.

 

[alohart]

I think you should pass on this if possible as there are too many unknowns here.

I agree.

The HV battery pack's state of health can be displayed by BMW's ISTA diagnostic software. This is just an estimate like the Batt. Kapa. max value displayed by the i3's service menu. I assume that this is the 70% value that this dealer quoted. That's what I'd expect from a 60 Ah battery pack (2014-2016 i3) but not from a 120 Ah battery pack which is typically very slow to degrade.

However, this is an Arizona car which could mean that its battery pack has spent a lot of time way too hot. Battery pack cooling doesn't occur unless an i3 is on, being actively charged, or its battery pack is being preconditioned. So if an i3 is parked in a hot garage or over hot asphalt, the battery pack could overheat. If this happens repeatedly, cell degradation would accelerate. I have always steered clear of used i3's from Arizona and Las Vegas because of this.

 

[Ashriot]

Interestingly, I just got off the phone with the manager who said they checked all the logs and never saw anything like that. They believe that the client just had buyer’s remorse and didn’t want the car.

They said their techs never saw any serious battery degradation either but he was hesitant to straight up tell me what the capacity was. He just kind of went with “All EVs have natural battery degradation, but this one isn’t out of spec” that type of response.

They also said they never saw or could find any record that the car was ever towed.

They said if I’m not comfortable I can back out. They don’t want to sell me a car that I’m not comfortable with.

Not sure what to do yet but they said I have some time to think it over. No hurry.

I appreciate everyone’s advice!

 

[Mondomensch]

If you haven’t already, I would obtain (purchase if necessary) both Carfax reports and the BMW internal system service record for any car you are considering buying. You’ll need the VIN and Carfax ordering is easy.

After I bought my used i3 I learned about online/ebay vendors who will sell you the PDF report of all dealer service visits from the BMW servers, typically for $6-8. I found the reports on my cars interesting and reassuring.