Charging / Battery Health Question

[Owner4523]

I am a new Tesla owner and I'm trying to wrap my head around all of information out there surrounding the long term health of your battery. Is there any harm in driving your car under 20% of battery? It seems like you want to be on the low side (10% or lower) when you arrive at a Super Charger. I'm just curious if I arrive home at 10, 15, or 18% then plug up to my home charger, I'm risking any sort of adverse effects on the battery by doing so?

Thanks!

 

[Big Earl]

I am a new Tesla owner and I'm trying to wrap my head around all of information out there surrounding the long term health of your battery. Is there any harm in driving your car under 20% of battery? It seems like you want to be on the low side (10% or lower) when you arrive at a Super Charger. I'm just curious if I arrive home at 10, 15, or 18% then plug up to my home charger, I'm risking any sort of adverse effects on the battery by doing so?

Thanks!

There is no harm in running it down that low. You'll want to charge it right away, since the state of charge will drop as the battery cools down. Don't plan on leaving it parked below 20%, especially in cold weather.

 

[AAKEE]

The real SOC doesnt drop if the battery cools down, only the displayed SOC.
This is a active choice from Tesla, as the SOC measured still is the same when the battery cools.
Any big difference in displayed SOC only happens if its very cold outside, like well below freezing.

The high voltage battery itself is very safe at low SOC. No need to worry about that.
We only need to make sure that the high voltage battery dokt get completely discharged (thats well below 0% on the screen), as this means the low voltage battery does not get charged from the high voltage battery which it need to be about daily. If it do not get charged, the car ends up not possible to wake up and probably need a new low voltage (12V) battery. (If you have a 16V lithium batt it needs to be charged.)

I often leave my car at lower SOC, working weeks means arriving at ~ 10-20% SOC and the car stays there or I do some short drives to the store, so it stay around 10-15% mostly during these weeks.

My M3P ’21 had minimal degradation after 2.5 years / 66K km.
It had not ended up as the M3P on teslafi charts with the lowest degradation if low SOC had been bad. (It’s well known from science/research that low SOC is not bad at all, so the conclusion do not cone from my car only).

 

[Owner4523]

The real SOC doesnt drop if the battery cools down, only the displayed SOC.
This is a active choice from Tesla, as the SOC measured still is the same when the battery cools.
Any big difference in displayed SOC only happens if its very cold outside, like well below freezing.

The high voltage battery itself is very safe at low SOC. No need to worry about that.
We only need to make sure that the high voltage battery dokt get completely discharged (thats well below 0% on the screen), as this means the low voltage battery does not get charged from the high voltage battery which it need to be about daily. If it do not get charged, the car ends up not possible to wake up and probably need a new low voltage (12V) battery. (If you have a 16V lithium batt it needs to be charged.)

I often leave my car at lower SOC, working weeks means arriving at ~ 10-20% SOC and the car stays there or I do some short drives to the store, so it stay around 10-15% mostly during these weeks.

My M3P ’21 had minimal degradation after 2.5 years / 66K km.
It had not ended up as the M3P on teslafi charts with the lowest degradation if low SOC had been bad. (It’s well known from science/research that low SOC is not bad at all, so the conclusion do not cone from my car only).

On a bit of a different note, do you know how TeslaFi determines battery capacity? On Tessie it gives you a default value, but you can change it: I don't see that option on TeslaFi. How does it know what the capacity of your battery is? (My car is the 2023 MY AWD 4680 battery.) I just starting using the software around 2,000 miles on my car, and about 5 months old so I want to be sure it knows what the proper starting point of the battery is.

I'm trying to figure out which program I want to use long term to track the health of my battery.

 

[AAKEE]

On a bit of a different note, do you know how TeslaFi determines battery capacity?

Teslafi doesnt show the capacity, As far as I've seen. I have used it since my forst Tesla was new. >3 yrs back.
Teslafi shows the range, and you can compare to the average from other cars.

On Tessie it gives you a default value, but you can change it: I don't see that option on TeslaFi. How does it know what the capacity of your battery is?

Tessie tries to find the matching capacity, as it is OTA it mostly is not correct at least as far as I have seen. Most often Tessie shows a too low original capacity, thus showing a lower degradation than the real one. It is possible to change the original capacity though.

(My car is the 2023 MY AWD 4680 battery.) I just starting using the software around 2,000 miles on my car, and about 5 months old so I want to be sure it knows what the proper starting point of the battery is.

I'm trying to figure out which program I want to use long term to track the health of my battery.

I think both track about as well.
Tessie seem to make a good job calculating the capacity in kWh and Teslafi shows the range.
I think it is a matter of your choice. If you get Tessie, make sure to learn the real origin capacity and change to that number.

 

[Owner4523]

Thanks, it looks like TeslaFi doesn't any cars to compare to mine with close to the same mileage. I'm still learning, do you suggest changing some of these settings to get a more accurate picture of my battery?

 

[Owner4523]

@AAKEE - I have been following your advice though.

 

[AAKEE]

Thanks, it looks like TeslaFi doesn't any cars to compare to mine with close to the same mileage. I'm still learning, do you suggest changing some of these settings to get a more accurate picture of my battery?

Include fleet over 60% charge
Set the within xx miles higher.
If there are few cars, increase the ODO eange to get more cars within.

Theres also som kind of setting to only include cars at the same region, you could change that if there are dimilar cars in other places.

 

[Owner4523]

Include fleet over 60% charge
Set the within xx miles higher.
If there are few cars, increase the ODO eange to get more cars within.

Theres also som kind of setting to only include cars at the same region, you could change that if there are dimilar cars in other places.

Thanks. How does this look?