December 2018. California.
I drive my Model 3 about 50 miles (80 km) a day during the week, and a bit less on weekends. I charge 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 RWD Long Range Model 3 was 310 miles when we bought the car, a later software update increased the range to 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 charge the car above 90% when you may need extra 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 quickly add more to the pack if I head out of town in any direction.
Most days I get home in the evening with 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.
I scheduled the car to start charging at 3AM each night. I plug the mobile charging cord into the 240V 30 amp clothes dryer circuit in my garage during the week. This provides 240V / 24 amps to the car, ~5.7 kW. 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 mobile 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 sent to 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).
Over the first nine months I charged my Model 3 to 60% on a daily basis. In December 2018 I fully charged the car to 100% State of Charge and got exactly 310 miles, which was full capacity of the pack at that time. Our Model 3 had 12,500 miles on the odometer at that time. Update: ten months later in October 2019 a full charge gave me 325 miles after a software update increased the Model 3 range – our car was 18 months old with 24,500 miles. So at 18 months any battery degradation occurring in the cells has not yet impacted our range estimates. 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 has stated that the Model 3 battery pack should last between 300,000 – 500,000 miles. I doubt I’ll put that many miles on my car, but I do expect the Model 3 battery pack to last a long time. I’ve talked with 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 several road trips including a 1400 mile trip to San Diego, and a 2700 mile trip to Albuquerque. 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 works for me. Others may want to set a higher SOC if 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 each morning. Whatever the case, my example shows that if you did adopt this charging strategy your battery pack will be just fine.