Here is an interesting battery degradation test of a two-year-old 2019 Tesla Model 3 Long Range, conducted by Bjørn Nyland.
The car has covered some 88,000 km (55,000 miles), but the key thing is that it was charged mostly using the AC on-board charger:
- DC charging total: 7,409 kWh (37%)
- AC charging total: 12,482 kWh (63%)
- Total: 19,891 kWh
That's opposite to Bjørn's former Tesla Model 3 Performance, which in about two years and 80,000 km (50,000 miles) lost about 8%, charging mostly (60% of energy) from DC fast chargers.
The question here is then whether this Model 3 LR, with similar mileage and age, will have significantly different results because of less DC charging?
Well, after applying the standard test procedure of charging, driving and interpretation of the results, Bjørn estimates the current battery capacity at 67.2 kWh (420.2 km covered times energy consumption of 159 Wh/km, plus remaining 0.4 kWh).
That's about 92% (8% battery degradation) out of 73 kWh when the car was new. That's basically the same result as in the case of Bjørn's former Model 3!
Two data points are of course not enough to draw any conclusions, but there are no significant differences. Maybe Bjørn's former Model 3 would have 8.5% with a couple more thousand miles on the odometer, but nothing really special for a noticeably different use case.
The main factor for battery, in this case, seems to be the mileage and age, probably also the time of sitting idle at high state-of-charge.
The average is close to 1% per 10,000 km (6,200 miles) and 4% per year within the first two years of both cars tested.
Depending on the rate of battery degradation over time (it might slow down), the drop after 200,000 km (124,300 miles) or within 5 years should be lower than 20% (80% of the range of a new car).