I drive my Model 3 about 50 miles (80 km) a day during the week, and a bit less on weekends. I charge my car every night in the garage. At the end of each day I pull into the garage, plug in, and don’t have to think about it again.
The EPA-rated range of a fully charged Model 3 is
310 325 miles (520 km). When charging the Model 3 you can set the car to charge to a specific state of charge (SOC) at any value between 50% and 100%. In this way, the car stops charging when it reaches the % SOC you’ve set. Tesla recommends charging between 50-90% for daily driving – depending on your needs – and to fully charge the car up to 100% when you think you’ll need the range on a longer trip.
I don’t fully charge my car. I set my daily charging level to 60%, which gives me about
185 195 miles / 313 km of rated range to start each day. After driving Toyota’s Rav4 EV for 5+ years (113 miles EPA rated range), I know that 195 miles is way more than I need on a typical weekday. And with Tesla’s Supercharging network I know that I can always quickly add more to the pack if I head out of town in any direction.
Most days I get home in the evening with 135-145 miles / 230 km in the pack, depending on how far and how fast I drove that day – and a few other variables. The 40-50 miles of rated range that I use on a typical day consumes about 15% of the battery’s full charge. So I’m usually cycling between ~45% and 60% SOC on a daily basis.
In terms of kWh, my daily 50 mile commute in the Model 3 uses, on average, 9 or 10 kWh from the pack each day. Somedays less, somedays more, depending mostly on weather and where I drive that particular day.
I scheduled the car to start charging at 3AM each night. I plug the mobil charging cord into the 240V 30 amp clothes dryer circuit in my garage during the week. This provides 240V / 24 amps, or about 5.7 kW, to the car. That rate of charging stores 23 miles of rated range in the pack each hour. Charging usually takes 2 hours.
Level 2 charging is about 85-90% efficient. So to replace the 9 or 10 kWh consumed each day, the mobil charging cord sends about 12 kWh to the car from the wall. I can download hour by hour electricity usage data from my utility, and this shows the amount of electricity consumed by the car during charging. The image below shows that from 3AM to 5AM over 11 kWh was sent to the car to return the pack to 60% SOC (see yellow highlighting below). You’ll also notice that our solar system made more electricity than we used that day from about 9AM to 5PM (See Solar Power Part 1 & Part 2 for more info on the solar system).
I drove 13,000 miles over the first nine months and charge my Model 3 to 60% on a daily basis. Last month I finally charged my car to 100% to see how many miles of rated range I’d get. The car reached exactly 310 miles, which was full capacity of the pack at that time. My example shows that charging the Model 3’s lithium ion battery pack to 60% on a daily basis does not affect your ability to fully charge when needed.
So why only charge to 60%? The Model 3 battery pack uses new 2170 lithium ion cells that are different from the 18650 lithium ion cells that power the Model S and X. Tesla CEO Elon Musk recently stated that the Model 3 battery pack should last between 300,000 – 500,000 miles. And given the amount of data showing Model S/X battery pack durability, I do expect the Model 3 battery pack to last a long time. But I’ve talked with a couple of people who work in this field, and for longevity the best state of charge for lithium ion cells is close to 50%. I realize these cells were designed and built to last, but I am hoping to get as many miles as possible out of my pack, and since the 60% SOC works for my daily needs I’ve adopted this approach.
We’ve taken our Model 3 on five road trips, including a recent 1400 mile trip to San Diego. During those trips I set the SOC higher and usually operate between 80% and 30% SOC while driving from one Supercharger to the next.
Summary: Charging to 60% SOC may not work for others, because they may drive more each day, or like to be prepared in case of unplanned trips, or maybe just prefer seeing over 250 miles of range in the pack each morning. So I don’t recommend that you adopt my approach. But my case shows that if you did adopt this charging strategy your battery pack should be just fine.