Is my battery toast?

[AAKEE]

But it's still better to have it sitting at 50% than 100% right? I know there is no concern having the car sit at a lower state of charge but I had thought you said a while back that higher states of charge reduces battery health faster.

It increases calendar aging vs, say, 50% fairly substantially, does it not? Isn't that the whole thing?

Yes, you are both correct, as @AlanSubie4Life also is, as always

We need to keep the answer in the context.
This was the statement I answered to:

It degrades pretty badly if left at 100%.

Compared to low SOC, 100% causes increased calendar aging/ degradation.

When comparing 100% to the usual “80%” theres most often not a big difference.
Look at 80% vs 100% on the blue 25C line.

There’s normally not a reason to leave the battery at 100%, but if it somehow happens its no reason to panic.

 

[MYoohMY]

My car has been at the body shop for months. This weekend the temperatures are in the negatives. I called the shop Friday to ask if they were going to charge up the car before the cold front hit. They said they’ll leave it inside and plugged in. They didn’t. Now it’s completely dead, won’t let me connect or anything. It will be sitting in 0 to -15 degree weather all weekend with a totally dead battery. Is this going to permanently damage my battery and negatively impact my range?

 

[jjrandorin]

My car has been at the body shop for months. This weekend the temperatures are in the negatives. I called the shop Friday to ask if they were going to charge up the car before the cold front hit. They said they’ll leave it inside and plugged in. They didn’t. Now it’s completely dead, won’t let me connect or anything. It will be sitting in 0 to -15 degree weather all weekend with a totally dead battery. Is this going to permanently damage my battery and negatively impact my range?

(moderator note)

I merged your new thread into this one because its the same general topic, and its already discussed in this thread.

 

[AAKEE]

My car has been at the body shop for months. This weekend the temperatures are in the negatives. I called the shop Friday to ask if they were going to charge up the car before the cold front hit. They said they’ll leave it inside and plugged in. They didn’t. Now it’s completely dead, won’t let me connect or anything. It will be sitting in 0 to -15 degree weather all weekend with a totally dead battery. Is this going to permanently damage my battery and negatively impact my range?

Cold is better for the lithium battery. The degradation from time is lower in cold, low state of charge is also good.

If the state of charge is low enough the lithium battery stops charging the low volt battery. The low volt battery will not like that and at least if it is a lead acid 12V batt, it need replacement after that.

The lithium battery will normally be safe for long time even if it was shut down and low temperatures are not bad. The low temp that makes the car display a lower SOC is artificially made up, so the real SOC will not droop from low temperatures.

I do not know if you refer to C or F. Tesla tell us in the manual to not leave the car for more than a day at below -30C (-22F), for the sake of the battery.

I would be very determined to set high requirements for that lower temp limit and be clear that any issue (even future issyes that can be couoled to low temperatures ) would be paid by the body shop if they handle the car outside the limits in the manual.
I would show them this and per mail or likewise make sure it can be proved in court that they did know about the limits.

The above would most probably make the body shop very interested in not have tge car outside in too cold.
(Same for letting the car go so low in SOC that the low voltage batt goes bad).

 

[MYoohMY]

Cold is better for the lithium battery. The degradation from time is lower in cold, low state of charge is also good.

If the state of charge is low enough the lithium battery stops charging the low volt battery. The low volt battery will not like that and at least if it is a lead acid 12V batt, it need replacement after that.

The lithium battery will normally be safe for long time even if it was shut down and low temperatures are not bad. The low temp that makes the car display a lower SOC is artificially made up, so the real SOC will not droop from low temperatures.

I do not know if you refer to C or F. Tesla tell us in the manual to not leave the car for more than a day at below -30C (-22F), for the sake of the battery.

I would be very determined to set high requirements for that lower temp limit and be clear that any issue (even future issyes that can be couoled to low temperatures ) would be paid by the body shop if they handle the car outside the limits in the manual.
I would show them this and per mail or likewise make sure it can be proved in court that they did know about the limits.

The above would most probably make the body shop very interested in not have tge car outside in too cold.
(Same for letting the car go so low in SOC that the low voltage batt goes bad).

Thank you for the very informative reply! My insurance company got involved and said they pay the shop to keep the car charged. So they also got on the shops case. I’m pretty sure the shop did replace the 12v battery. The HV pack seems to be fine and charged back up. Do you know if there is a way for me to get the HV battery tested? I do not have the car back yet despite them saying it’s been done for weeks. My insurance company said they’re still just waiting for the paperwork from the shop.

 

[AAKEE]

Thank you for the very informative reply! My insurance company got involved and said they pay the shop to keep the car charged. So they also got on the shops case. I’m pretty sure the shop did replace the 12v battery. The HV pack seems to be fine and charged back up.

Do you know if there is a way for me to get the HV battery tested?

There is a few ways, but first indication would be the displayed range at 100%.

I would say that it is not needed to check.
If you still would like to check I would not recommend leave the car away to someone else*.
I would use scan my tesla to check all interresting values. I guess you do not have any references from before but we can help with that.
Tha capacity, imbalance and CAC values could be checked to make sure all is within the normal values.

*) From what Ive seen from battery test certificates starting to be used by companies selling used EV’s they do not show you anything that would help you with your specifik case.