Published on December 7th, 2018 | by Kyle Field0
How Much Should You Charge Your Tesla Overnight To Keep Your Battery Healthy & Software Sane?
December 7th, 2018 by Kyle Field
Tesla’s stance on how to charge its vehicles overnight continues to evolve as it processes volumes of real-world data from its fleet of Model 3s and their 2170 cells. Kim, from the Like Tesla YouTube channel, had been charging her Model 3 up to 70% for the 11,000 miles she had owned it. She found that in that time, the stated range of the car with a full charge had dropped from 310 miles to 260 miles.
That is a staggering loss of capacity and far beyond what we have come to expect from hundreds of thousands of miles on individual Tesla Model S and X vehicles. Even more shocking, Kim’s Tesla had been babied from a charging standpoint, only being charged up to 70% every night, per Tesla guidance. Kim used her platform to make a video about her findings and took the car in to Tesla to figure out what was going on. Tesla shared some instructions, which Kim summarized in her video.
- Charge to 90% nightly. Leave vehicle plugged in after reaching 90%. Range should increase within several weeks.
- If unsuccessful, charge to 100%. Leave plugged in until charging stops.
- Drive down to under 10% and repeat 100% charge 2–3 times until full recalibration occurs.
What she learned was that the gauge that displays the mileage of the car essentially gets trained and that the new recommendation is to charge the car up to 90% overnight and to leave it plugged in after it is charged. This starts what is essentially a re-training process that reminds the car how much battery pack it has, resulting in the displayed range increasing over a few weeks.
In other words, the car’s battery didn’t actually lose a dramatic amount of energy storage capacity. Rather, because Kim kept the charge at 70% or lower, some portion of the car’s software became convinced the car had less range than it really had.
To raise awareness of the issue, Kim tweeted it out to Elon, asking the same question. In typical Elon fashion, he shared that it’s not worth it to keep the car’s charge below 80% each night, and that even 90% is fine.
Not worth going below 80% imo. Even 90% is still fine. Also, no issue going to 5% or lower SoC.
— Elon Musk (@elonmusk) December 1, 2018
The new insights are helpful lessons for those who are new to electric cars and good updates to the guidance on overnight charging for those who have already established a normal charging routine.
— LikeTesla (@LikeTeslaKim) December 5, 2018
Check out the video below for a more thorough unpacking of the whole experience with the Like Tesla Model 3, but be warned: It starts off with a healthy dose of “family business” as Like Tesla just launched its official website and store, so the video opens with a few minutes of that.
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