Strange battery behaviour

[AmphySuperTram]

Hi guys. Model 3 from September 2020.
I always charge my car every night up to 75%. I usually drive 40 km a day and use 6% of battery. Then I bring the charge back to 75% at night. Sentry always disabled. Whenever I use the car more and get to 66% approximately, if I park it without charging it and I use it again after a few hours, i find It at 63% (in the image attached from 64% to 61%). There's a 3% of charge that goes disappear...

How come there is such sudden and unjustified consumption? The car regularly goes in deep sleep.
Does it make sense to calibrate the battery? What do you normally do to prevent any damage?

Thanks!

 

[GtiMart]

There's no damage and there's no "unjustified consumption". The battery percentage is just an estimate, not a fully precise value. After you stop driving, the car might consume a bit of energy for the 15-30 minutes it stays awake before sleeping. Maybe that crosses the rounding into one lower percent. After that, as the car sleeps the BMS might recalculate and come up with a different estimate, for various reasons. Nothing to worry about and nothing to do.

 

[jdcollins5]

If the temperature of the battery decreases, so will the BMS estimate. Normal.

 

[AmphySuperTram]

The percentage that dissapear now is like 5% ... from 65% to 60% ...

 

[jjrandorin]

Its colder than it was in October when you first posted this.

 

[AmphySuperTram]

But if I'm planning a long trip, I can't rely on the battery estimation if it decreases by 5% all of a sudden..
The battery has this behaviour also with you?

Thanks.

 

[jjrandorin]

But if I'm planning a long trip, I can't rely on the battery estimation if it decreases by 5% all of a sudden..
The battery has this behaviour also with you?

Thanks.

If you were planning a long trip, you would be setting it to a higher percentage, not 75% Cold can make the estimation drift more when it sits, from battery temperature.

 

[AmphySuperTram]

Ok.. so I can assume that is everything normal... Thank you so much.

 

[jjrandorin]

Ok.. so I can assume that is everything normal... Thank you so much.

I have read probably more than a thousand posts on "the battery" and have yet to see one where there was an actual issue, that wasnt reported as an error by the cars information, so yeah I feel everything is normal.

 

[AAKEE]

If the BMS is overestimating the capacity, the displayed SOC might be to high. This gets adjusted quite soon when in Park with low load on the battery. This is of course more easy to see after longer drives.

And the other way around, if the BMS underestimates the capacity it will increase after the drive.

On a longer term, when the battery cools off after a drive (takes several hours, and it need to be quite cold outside) the displayed SOC will be lower because the battery is cold.