Model Y Battery Calibration

[SFNM Jack]

I have a new MY with 600 miles on it. Have yet to charge it past 70% and always at 13a on my 14/50 outlet. Low and slow. Is there any real science behind this “calibration” from Tesla or anyone else? I’ve read in multiple places and seen studies that show low and slow to be the best way to preserve battery capacity. Should we really be pushing 100% and almost complete discharge to change a number on the screen? I’m skeptical but if this really helps the battery then I’d do it. What does Tesla say about “calibration”. don’t recall seeing it in the manual…

 

[jcanoe]

I have a new MY with 600 miles on it. Have yet to charge it past 70% and always at 13a on my 14/50 outlet. Low and slow. Is there any real science behind this “calibration” from Tesla or anyone else? I’ve read in multiple places and seen studies that show low and slow to be the best way to preserve battery capacity. Should we really be pushing 100% and almost complete discharge to change a number on the screen? I’m skeptical but if this really helps the battery then I’d do it. What does Tesla say about “calibration”. don’t recall seeing it in the manual…

By charging at 13A each charging session takes longer and is less efficient than if you charged at 32A using the Tesla Mobile Connector and the 14-50 adapter. There is fixed overhead whenever the Tesla is powered on. The faster you complete the charging session the less the overhead is a factor in the overall charging efficiency. Low and slow does not matter when charging at home as even the highest charging rate (48A) on a 60A circuit is 1/7th the capacity of the Tesla battery and not an issue.

When new the Tesla vehicle battery management system (BMS) has limited available data about the battery pack. Over time the BMS collects data on state of charge of the cells in the battery and refines the upper and lower bounds of the battery when fully charged and discharged. There are several things as a Tesla owner you can do to let the BMS continue to collect data and refine the algorithm that establish the state of the battery. Periodically charge above 95%, then operate the Tesla vehicle so the battery charge is depleted down to 30% or lower over several days if needed. This helps the BMS refine the upper and lower bounds of the battery. Another thing that Tesla owners can do is set Sentry mode to be off when parked at your home location (at least some of the time.) Periodically the BMS will measure the open cell voltage (OCV) of the cells within the battery. This can only be performed when the Tesla vehicle is in a sleep state and the high voltage battery is disconnected from the Tesla vehicle. Sentry mode and Summon standby prevent the Tesla vehicle from entering a sleep state.

 

[SFNM Jack]

By charging at 13A each charging session takes longer and is less efficient than if you charged at 32A using the Tesla Mobile Connector and the 14-50 adapter. There is fixed overhead whenever the Tesla is powered on. The faster you complete the charging session the less the overhead is a factor in the overall charging efficiency. Low and slow does not matter when charging at home as even the highest charging rate (48A) on a 60A circuit is 1/7th the capacity of the Tesla battery and not an issue.

When new the Tesla vehicle battery management system (BMS) has limited available data about the battery pack. Over time the BMS collects data on state of charge of the cells in the battery and refines the upper and lower bounds of the battery when fully charged and discharged. There are several things as a Tesla owner you can do to let the BMS continue to collect data and refine the algorithm that establish the state of the battery. Periodically charge above 95%, then operate the Tesla vehicle so the battery charge is depleted down to 30% or lower over several days if needed. This helps the BMS refine the upper and lower bounds of the battery. Another thing that Tesla owners can do is set Sentry mode to be off when parked at your home location (at least some of the time.) Periodically the BMS will measure the open cell voltage (OCV) of the cells within the battery. This can only be performed when the Tesla vehicle is in a sleep state and the high voltage battery is disconnected from the Tesla vehicle. Sentry mode and Summon standby prevent the Tesla vehicle from entering a sleep state.

I’m getting 95% efficiency at 13amps on the 14/50…. I’ll try 32amps and see if it’s any better…. Thx for the tip on sentry mode. Mine is in the garage so really not need for it anyway…. I’ll make that change tonight. Road trip tomorrow…. 130 round so I’ll crank her up to 95%…. I’m reading 327 miles capacity today so I assume that’s good.

 

[jcanoe]

I’m getting 95% efficiency at 13amps on the 14/50…. I’ll try 32amps and see if it’s any better…. Thx for the tip on sentry mode. Mine is in the garage so really not need for it anyway…. I’ll make that change tonight. Road trip tomorrow…. 130 round so I’ll crank her up to 95%…. I’m reading 327 miles capacity today so I assume that’s good.

Yes, 327 mile estimate is what you would expect for a new Long Range Tesla Model Y; the 330 miles is the EPA estimate, not based on temperature, wind, road conditions or your driving history. Don't be disappointed when the actual range is lower (15% to 25% lower depending on temperature and other factors.)

Become acquainted with A Better Route Planner (ABRP) as a trip planning tool. Available for your computer as a web based application or for your phone ABRP enables more accurate estimate of range and any needed charging stops.

Besides those factors the biggest obstacle to achieving good driving efficiency is speed. Try and limit your speed to a maximum of 70 MPH even though it is tempting to drive at much higher speeds in the Model Y.

 

[Rocky_H]

Should we really be pushing 100% and almost complete discharge to change a number on the screen? I’m skeptical but if this really helps the battery then I’d do it.

Well no, definitely not. Those are two completely opposite things. Trying to tune in the estimation algorithm is for the owner. That's to give people a warm fuzzy feeling about seeing the number on the screen look closer to what they want to see. But it's certainly doesn't "help the battery". In fact it's the opposite. As you correctly assumed, running the battery to the extreme high and low ends is a tiny bit hard on the battery life. So it's trading off a little bit of harm to the battery just to make people feel better.

 

[rjpjnk]

^^^ Exactly! Thanks for clearing this up Rocky_H.
The calibration process has nothing to do with battery health or getting the most range from your battery. It's just about fine tuning the estimator itself. I'm not sure why anyone would want to perform this.

 

[SFNM Jack]

Just want to report in on moving to 32 amp vs 13 amp charge rate. It did produce 1% better efficiency from 95% to 96%…. Think I’m sticking with the low and slow method and completely ignoring the “calibration” bunk.