I Plan To Keep My Tesla Model 3 Until I Die: How Can I Make My Battery Last That Long?

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I will be 84 this year. Except for several corrected orthopedic issues, I’m still healthy, and based on family history, I could last another 10 years until age 94 or longer. By that point my kids will probably take away my smartphone/key, or at least remove the Tesla App from my phone. Even then, my wife, kids, or grandkids will probably be willing to drive me, so we may be using our Tesla even longer than that.

Figure 1: My Tesla Model 3 and ebike at a 98-stall Tesla Supercharger in Baker, California. February 16, 2022. Fritz Hasler photos.

My Tesla Model 3 Long Range was purchased on October 19, 2019, which means that as I write this article today, I have reached the 41/2-year anniversary of owning my Tesla. My odometer now reads 124,337 miles. How can I best ensure that my Model 3 will reach its 141/2-year anniversary? I will be at ~400,000 miles if I keep driving at my current rate. We commute 3000 miles round trip from our winter home in Northern Utah to our summer home in Northern Wisconsin and back every year. Our Tesla will probably still be making that trip as we get older even if we need to have a child or grandchild do the driving for us. We also commute regularly from Northern Utah to our daughter’s home in Southern Utah in the winter. Therefore, our annual mileage will probably not reduce much as we get older.

In the next 10 years, I would expect to have normal service expenses as we go from ~125,000 to ~400,000 miles on the car. With a simple electric motor and single-speed transmission, my expenses should be much less than the expenses for a car with a complex internal combustion engine, complex automatic transmission, complex exhaust and emissions control system, cooling system, brakes, etc., etc.

However, I don’t want to have to spend ~$15,000 to replace the expensive battery on my EV. We have been instructed by Tesla to not charge the battery above 80% or let it go below 20% if we want maximum battery life. I’ve done this religiously at home. Also, I rarely charge above 80% on cross-country trips because charging above 80% is so slow. Before I leave for a long first leg on a cross-country trip, and rarely when the distance between chargers is above 120 miles, I will charge to 90%. However, I have never charged to 100%. Rarely, on long stretches between Superchargers, I will arrive at 10% or below. Since arriving below 20% state of charge is also stressful on the battery, that should also be part of your calculation about your state of charge when you start a travel leg. My top speed is never over 75 mph. If I see that my estimated state of charge on arrival is less, I reduce my speed.

When my car is charging, if I set the charge limit to 100%, my car will compute the maximum battery mileage range. It now gives me 280 miles. Since the original EPA range for my vehicle was 310 miles, a rough estimate of the state of the battery is 280/310 miles, or ~90%. According to Battery University, 90% is the optimum end of life for a lithium-ion battery. Am I done? I don’t think so! I have read reports that battery degradation goes slower in later battery years. Also, I purchased the Long-Range version of the Model 3 and I will still have enough range for cross country driving when my battery reaches 50% of its original capacity. However, I will need to ditch the two big aerodynamics-destroying ebikes that I always carry on a tray type carrier on back during long trips.

Am I doing everything I can to prolong the life of my battery? According to Battery University: The optimum state of charge for lithium-ion batteries is 50%. That means that if your driving distance for a given day is low, you should be operating between 60% and 40%. On a Tesla, it’s easy to set the maximum state of charge. I just reduced mine from 80% to 60%. This should give me plenty of range on days when I have no long trips planned. However, that means that I will need to plan ahead and raise my maximum charge to 80% on days that I expect to drive further. That can usually be done with the app when I wake up on the morning of the day when I need more charge.

Figure 2: L2 charging my Tesla Model 3. April 20, 2024. Fritz Hasler photo.

We’ve all heard that fast charging (Supercharging) your battery is more stressful than trickle charging. However, I’ve seen the results of recent studies that say that supercharging your battery regularly will not shorten its life significantly. Still, according to the Battery University, rapid charging is much more stressful to your battery. I have a L2 charger in my garage in northern Utah. I have NEMA 14-50 outlets with 240V power in my garages in southern Utah and northern Wisconsin. I use the mobile connector charging cable which came with my car in those locations. In all of those locations, I am charging at a rate of ~24 miles/hour or ~6 kW. This ensures that I can recover from a long outing or the last day of a long trip overnight.

However, if my mileage driven on a given day is only 40 miles or less, I could recover that charge overnight at a rate of 4 miles/hour on a 110V trickle charge. Would that increase the life of my battery? I’ve seen some reports that say that would actually decrease the life of the battery. However, that would go against the Battery University guidance. In northern Utah where I have an L2 charger, I could plug my Tesla Mobile Connector into 110 V. I could then use the 220 V L2 charger on long trip days and the Mobile Connector attached to 110V on those short driving days.

Does anyone have data comparing battery degradation at 220V versus 110V? If so, please let me know in the comments section.

What about the case of extended storage (not driving your car for an extended period of time)? According to Battery University, storing your battery at 100% state of charge would be very stressful. If you store your car at 25°C (77°F) you would reduce the capacity of the battery to 80% after one year. However, if you reduce the battery state of charge to 40%, you would only reduce the capacity of the battery to 96% after one year.

Referral Program: Tesla has reactivated its referral program. If you find any of my articles helpful to you, please use my referral link: https://ts.la/arthur73734 (be sure to use it when you make your order). If you are buying a new Tesla and use my link, you’ll receive $1000 off your purchase price for a Model S or X, or you will get $500 off for a Model 3 or Model Y). You will also get 3 months of Full Self Driving (Supervised).

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Arthur Frederick (Fritz) Hasler

Arthur Frederick (Fritz) Hasler, PhD, former leader of NASA Goddard Space Flight Center Scientific Visualization & Analysis Laboratory (creator of this iconic image), and avid CleanTechnica reader. Also: Research Meteorologist (Emeritus) at NASA GSFC, Adjunct Professor at Viterbo University On-Line Studies, PSIA L2 Certified Alpine Ski Instructor at Brighton Utah Ski School.

Arthur Frederick (Fritz) Hasler has 123 posts and counting. See all posts by Arthur Frederick (Fritz) Hasler