Does leaving a battery at low state of charge cause degradation or just inconvenience?

[Jonnymack74]

So I have a model s 2019. Just got back from a long drive from Scotland. I arrived home with 8% Battery this evening. Plugged in ready for the charge with usually starts during me off peak..from 11:30. Checked the app 3 hours later and battery % had gone down to 3%

Is this normal?

 

[AAKEE]

So I have a model s 2019. Just got back from a long drive from Scotland. I arrived home with 8% Battery this evening. Plugged in ready for the charge with usually starts during me off peak..from 11:30. Checked the app 3 hours later and battery % had gone down to 3%

Is this normal?

After a drive, the displayed /calculated SOC will be updated with the measured (real) SOC*.

If the SOC seems to ”drain” after a drive when the car is sleeping (not using Sentry or heat etc.) the reason is that the real SOC was lower than the calculated SOC, and the reason is most often due to the BMS overestimating the battery capacity.

You might wanna perform a BMS calibration (to ”show” the battery capacity to the BMS).
How doyou charge normally, and how much do you drive?

*) State of charge can not be measured during a drive. The State of charge is defined as the cell resting (OCV) voltage. During a drive, the car use the calculated energy in the battery (SOC x capacity), and calculates the current SOC by reducing the last known SOC with the used energy. After the drive the calculated SOC is adjusted when the SOC can be measured.

 

[Jonnymack74]

After a drive, the displayed /calculated SOC will be updated with the measured (real) SOC*.

If the SOC seems to ”drain” after a drive when the car is sleeping (not using Sentry or heat etc.) the reason is that the real SOC was lower than the calculated SOC, and the reason is most often due to the BMS overestimating the battery capacity.

You might wanna perform a BMS calibration (to ”show” the battery capacity to the BMS).
How doyou charge normally, and how much do you drive?

*) State of charge can not be measured during a drive. The State of charge is defined as the cell resting (OCV) voltage. During a drive, the car use the calculated energy in the battery (SOC x capacity), and calculates the current SOC by reducing the last known SOC with the used energy. After the drive the calculated SOC is adjusted when the SOC can be measured.

How do I do a bms calibration?

I set off with 85% from a trickle charge and needed 3 supercharge stops in Perth, Abington and Tebay. Driving was a mixture of Scottish Highland roads to a max of 60 and mway. Mway was between 70 and 80 mostly with a little at 50 for roadworks.

I've just remembered it did something similar when I had 14% in Essex, went for a suit fitting for about hour and half, came out it was 8% so no chance to get to south Mimms.. needed a slow charge at tesco for an hour to get enough to get to a supercharger.