20-80%. Who really does it? Is it a myth?
I've had my 2022 M3 DM for 3 years now, bought on a 4yr finance agreement at 1yr old. My intention is to return is at the end of the agreement, if I can find something suitable to replace it with.
This was my first EV. Despite having owned a PHEV, I thought this would be a very different experience. So I did research. Lots of it.
Everything I read about the battery seemed to point to the 20-80% rule, to guarantee longevity. Well, as selfish as it may be, this car goes back in 4 years. I don't really care about "longevity". How bad can it be?
Well, for the last 3 years and ~40K miles, I've treated my M3 like a petrol car. Almost all of my charging is done at home, and I always charge to 100%. I regularly use the car for a 250+ mile round trip, and return home with <5% charge (an artform in itself).
As the end of the warranty is up before it goes back to the finance company, I thought I'd get Cleevely out to give it a quick once-over. They were really helpful, and spotted a few snags that I got Tesla to sort.
The thing that surprised me most was their assessment of the battery health. They performed the Service Mode health check, and concluded than the battery is still at 94% of original health at 45K miles.
This made me question how much benefit I'd have gained by following the 20-80% guidance.