Possible main battery failure?

[camthehombre]

I've done a lot of looking around but I think I'm having main battery issues and want some other opinions before I bother Tesla.

-Preheated car and drove 50 miles (mostly flat) around 40 degrees outside and it used 30% (75 miles range) of my battery. Normally I make this same drive around 50-80 degrees and use less than 50 miles range.

-Supercharging takes a long time to start. I plug in and it takes upwards of 2 minutes to start charging when it used to be a few seconds. With this, I used to see 118 kW charging at low SoC, but lately the highest I've seen in right around 60 kW.

-My car normally charges to 250 miles at 100% with the 5% degredation that I have. Lately when it get's past 90% the charge time varies wildly ((will jump from 50 minutes to 20 minutes) and then at the end just says charging. It still adds a bit of range but there is no time shown, and sometimes the charge stops at 240 miles, and others at 247.

-Lastly, I feel like I've lost some "umph". I know lower SoC can mean less power, but I don't feel like I get anywhere near what I used to. I'll try and video it and see if it's the same as the past.



Any signs that people know of that a main battery is going out? I've read a lot of threads of people having issues, but no real mention of the warning signs except the MCU stating something. No alerts show on my MCU. Had the car about a year (it's a used 2014, now has 111k miles on it), never had issues like this in the cold last year (and I was running 21's then). Thanks.

 

[Tam]

...Supercharging takes a long time to start...

Super slow to start does happen in cold weather.

...It still adds a bit of range but there is no time shown, and sometimes the charge stops at 240 miles, and others at 247....

That sounds normal. Charging is fast when it's empty and it is super slow when it reaches its fullness.

...Any signs that people know of that a main battery is going out?...

Model S and X do not have degradation warranty while Model 3 does at 70%.

There's no warranty on charging speed or slowness either.

You know your main battery is bad when it is unable to hold a charge.

There's some tools such as

Using TM-Spy to see Model S data.

that can tell you whether each individual brick (composed of 74 cells) out of 96 (=7,104 cells) can hold a charge or not.

 

[camthehombre]

Is 2ish minutes normal to start? Mine has been taking a while to start since this summer, but it's getting worse which could be due to the cold.

I understand that it get's slower, but it used to say 50 minutes and would actually take that long. Now it says 20 minutes and will continue (basically trickle) charging for another 1-2 hours. It will randomly stop with a different charge percentage which is what I find weird.

I just wondered if this was part of the warning signs to it going out.

I'll try that TM Spy, but I scheduled an appointment since I have a couple other things I want them to look at. She said the 12v was getting a low warning even though I wasn't seeing it. She said she was more concerned that I wasn't getting an error on my end than anything else. Not sure if it's from my dash cam, as I can't imagine the draw off of that is enough to change my driving range that much. Either way I unplugged it to see if that might be the case. *shrug*

-Cam

 

[tga]

Super slow to start does happen in cold weather.

Only if the battery is cold. I've SC'ed in 0F weather after an hour of highway driving and it starts charging normally. Something sounds fishy with the OP's car.

 

[camthehombre]

Only if the battery is cold. I've SC'ed in 0F weather after an hour of highway driving and it starts charging normally. Something sounds fishy with the OP's car.

Thank you! I only supercharge after the car is warmed up because the nearest supercharger is half hour away, and the one I normally use is 50 minutes away. Just this morning I had an error pop up about car unexpectedly shutting down. I I didn’t see anything else as it disappear near instantly. Glad I have an appointment on Monday!

 

[N..8]

Sounds like the main battery is cold and that you are also about to loose the 12v battery. If the 12v battery is going out then you will have the main battery online more often when the car is at rest because of the drop in voltage on the 12v that it keeps closing the HV contacts to charge. Also if you only have been charging in up to 70 / 80% for a long time the BMS calculation could be a little off. I think that it's just the cold on the battery and during this time of year everyone gets taken by surprise on how a cold soaked battery effects range. If you had TM-spy you can see that the battery needs to be at about 56 degrees to have 4 ticks on reduced regen and the ticks don't go away until the battery hits 60 degrees. That's a lot of heater action if the car has been sitting outside or in a 30 degree garage.

 

[ucmndd]

All that sounds like "it's cold".

 

[BerTX]

All that sounds like "it's cold".

Yeah, my reply was going to be "Welcome to your first winter in a Tesla".

 

[camthehombre]

Yeah, my reply was going to be "Welcome to your first winter in a Tesla".

This isn't my first winter with a Tesla, and none of these problems existed last year. Sure usage was up, but not 50% after I've preheated the battery. Same with supercharging, I never supercharge cold and it never used to take more than a few seconds, but now minutes sometimes? And my charging (even last winter) would say 15 minutes remaining and would end after 15 minutes, not continue for 2+ hours at times. I get that there are issues that arise with the cold, but none of this seems normal from last year or like other things I've read about... just trying to cover my bases, just seems "off".

 

[BerTX]

This isn't my first winter with a Tesla, and none of these problems existed last year. Sure usage was up, but not 50% after I've preheated the battery. Same with supercharging, I never supercharge cold and it never used to take more than a few seconds, but now minutes sometimes? And my charging (even last winter) would say 15 minutes remaining and would end after 15 minutes, not continue for 2+ hours at times. I get that there are issues that arise with the cold, but none of this seems normal from last year or like other things I've read about... just trying to cover my bases, just seems "off".

It is probably worth getting it checked. Now that I think of it, each of those symptoms is not abnormal, but maybe ALL of them could be. 99% sure that the answer will be that everything is "within normal parameters", but there is always that 1%...

 

[camthehombre]

It is probably worth getting it checked. Now that I think of it, each of those symptoms is not abnormal, but maybe ALL of them could be. 99% sure that the answer will be that everything is "within normal parameters", but there is always that 1%...

I am hoping all is well. When she told me on the phone that my 12v was showing low on her end but not my end I wondered if that could be causing issues too. I have no idea what the symptoms of a failing 12v are on a Tesla as I've never had it before...except possibly now.

 

[camthehombre]

Follow up - It was the 12v battery. They told me it was draining the HV battery because it was constantly trying to recharge the 12v. Or at least that's how I understood it. I got it replaced for $210 ($150 for the battery and $60 for labor) and the problem is now gone. I drove back home at about 20 degrees outside, used 55 miles of range on a 50 mile drive, but the Wh/mi were at 330. Calculates to the exact amount I expect to be used. This was with the battery being cold, and subsequent drives with the battery warm have all been where they used to be. Thanks again for the help everyone.
-Cam

 

[TMeister]

Nice of you to follow up with your solution. Yet another symptom that leads to 12v battery problems.

 

[camthehombre]

Nice of you to follow up with your solution. Yet another symptom that leads to 12v battery problems.

I wanted to follow up because I honestly hate when people have issues and others pitch in with possible solutions and there is no follow up. How else are we supposed to learn what the fix was to certain problems?