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Do you have a source? That is really interesting if so! I'll plug my car in more often then. I remember seeing Elon Musk say that our Model 3 was rated for 150

by mdeeks 3y ago

Do you have a source? That is really interesting if so! I'll plug my car in more often then. I remember seeing Elon Musk say that our Model 3 was rated for 1500 recharge cycles. Our warranty is for 70% capacity after 8 years or 120k miles. That hints to me that cycling is the main cause of degradation. https://www.tesla.com/support/vehicle-warranty https://www.tesla.com/support/vehicle-warranty

throwaway5959 3y ago
Cycle count is the issue, not age. Think about laptops that are heavily used on battery vs not. There are taxis that have more degradation from fast charging and massive cycle counts than cars that are many years older.
lolc 3y ago
From what I remember, a li-ion cycle means a full range charge and discharge. Charging 10 percent is just 10 percent of a cycle. And discharging at low charge state causes more wear. Also fully charging is worse than just going to 70 percent charge. So ideally you hover around the middle with small cycles. Whether this is all true for Tesla's batteries I don't know. But I would assume that they do count a partial charge as a partial cycle and you shouldn't be penalized for intermittent charging. I'd certainly try to stay above 30 percent charge as much as possible. And use slow charging, because that's less wear too. So plugging it in every night at home should be less wear than the eventual quick charge from low. Even if the warranty doesn't distinguish these nuances, it's probably easier to manage regular home charging with better results too.
conjecTech 3y ago
If you do the math on that cycle count, you'll see its several times the warrantied amount. 1500 charges at 80% for a standard range M3 is over 300k miles. I think they probably picked that value to align with norms of other warranties rather than reflect any kind of real risk. They released some charts as part of their impact report showing 12% degradation at 200k miles, which lines up pretty well w/ the 1500 charges. [1] Most people drive about 10k miles/year, which would maybe be 50 cycles/year, and obviously the batter is unlikely to last 30 years. [1] https://electrek.co/2023/04/25/tesla-update-battery-degradation/ https://electrek.co/2023/04/25/tesla-update-battery-degradat...

by mdeeks 3y ago

throwaway5959 3y ago

Cycle count is the issue, not age. Think about laptops that are heavily used on battery vs not. There are taxis that have more degradation from fast charging and massive cycle counts than cars that are many years older.

lolc 3y ago

From what I remember, a li-ion cycle means a full range charge and discharge. Charging 10 percent is just 10 percent of a cycle. And discharging at low charge state causes more wear. Also fully charging is worse than just going to 70 percent charge. So ideally you hover around the middle with small cycles. Whether this is all true for Tesla's batteries I don't know. But I would assume that they do count a partial charge as a partial cycle and you shouldn't be penalized for intermittent charging. I'd certainly try to stay above 30 percent charge as much as possible. And use slow charging, because that's less wear too. So plugging it in every night at home should be less wear than the eventual quick charge from low. Even if the warranty doesn't distinguish these nuances, it's probably easier to manage regular home charging with better results too.

conjecTech 3y ago

If you do the math on that cycle count, you'll see its several times the warrantied amount. 1500 charges at 80% for a standard range M3 is over 300k miles. I think they probably picked that value to align with norms of other warranties rather than reflect any kind of real risk. They released some charts as part of their impact report showing 12% degradation at 200k miles, which lines up pretty well w/ the 1500 charges. [1] Most people drive about 10k miles/year, which would maybe be 50 cycles/year, and obviously the batter is unlikely to last 30 years. [1] https://electrek.co/2023/04/25/tesla-update-battery-degradation/ https://electrek.co/2023/04/25/tesla-update-battery-degradat...