Which way is better for the battery?

[Candleflame]

We don't know that. If you regularly charge to 90% the rated range is higher, but that's not equal to battery life, and may just be the way the algorithm works.

yeah we do. The car uses the same lithium ion cells everyone else uses and batteries of lithium ion type undergo the least reaction while being half charged. However, in a car like a Tesla there are lots of factors which affect longlivity...

 

[jerry33]

yeah we do. The car uses the same lithium ion cells everyone else uses and batteries of lithium ion type undergo the least reaction while being half charged. However, in a car like a Tesla there are lots of factors which affect longlivity...

Except for the chemistry which Tesla helped develop. I'd suggest they are not exactly the same as what everyone else uses.

 

[David99]

Except for the chemistry which Tesla helped develop. I'd suggest they are not exactly the same as what everyone else uses.

They don't have some magic ingredient making these cells fundamentally different from every other Lithium battery. The fact that Tesla recommends to only charge as much as needed and provides a slider all the way down to 50% shows that. Every Lithium battery expert agrees that high voltage (= high state of charge) has a negative effect on longevity of the battery. Tesla definitely has top quality cells that last longer than cheapo cells. Tesla also has excellent thermal management. It all helps, but the cells are fundamentally the same and the effects of aging are the same.

 

[TexasEV]

They don't have some magic ingredient making these cells fundamentally different from every other Lithium battery. The fact that Tesla recommends to only charge as much as needed and provides a slider all the way down to 50% shows that. Every Lithium battery expert agrees that high voltage (= high state of charge) has a negative effect on longevity of the battery. Tesla definitely has top quality cells that last longer than cheapo cells. Tesla also has excellent thermal management. It all helps, but the cells are fundamentally the same and the effects of aging are the same.

It may be a statistically significant difference from 50 to 90% but no one has shown that it's a clinically meaningful difference, as we say in the clinical trials business. The Roadster has a standard charge of 90% and the Plug-in America battery survey showed 80-85% capacity at 100,000 miles. The Model S battery technology has improved since then. How much better could a lower setting of 50% possibly be, and for most owners would that slight improvement in capacity after many years be worth crippling the car's range like that?

 

[djp]

It may be a statistically significant difference from 50 to 90% but no one has shown that it's a clinically meaningful difference, as we say in the clinical trials business. The Roadster has a standard charge of 90% and the Plug-in America battery survey showed 80-85% capacity at 100,000 miles. The Model S battery technology has improved since then. How much better could a lower setting of 50% possibly be, and for most owners would that slight improvement in capacity after many years be worth crippling the car's range like that?

It's not crippling if you don't need the range. My Roadster is a daily driver and I generally keep the SOC between 40%-60%. The battery is approaching six years old and so far I have zero range loss. I'm liking my clinical trial so far.

 

[ReddyLeaf]

...How much better could a lower setting of 50% possibly be, and for most owners would that slight improvement in capacity after many years be worth crippling the car's range like that?

Ha, even at 50% the 70D has nearly 2x the range of my 2011 Leaf. I find the 70D has sufficient range, even charging on L1 and leaving it at 50% (except on road trips). I guess that's the beauty of having two EVs, drive the smaller and more nimble Leaf in town, and the luxury largess road tripping.

 

[MileHighMotoring]

Ha, even at 50% the 70D has nearly 2x the range of my 2011 Leaf. I find the 70D has sufficient range, even charging on L1 and leaving it at 50% (except on road trips). I guess that's the beauty of having two EVs, drive the smaller and more nimble Leaf in town, and the luxury largess road tripping.

That's my mindset too - I charge to about 165 miles, so I guess that's 60%, and it's double the Leaf's range. I plug it in when I see it go double-digits (99 miles or less)

 

[Canuck]

It's not crippling if you don't need the range. My Roadster is a daily driver and I generally keep the SOC between 40%-60%. The battery is approaching six years old and so far I have zero range loss. I'm liking my clinical trial so far.

Interesting. Thanks for that information. It accords with what we know from research:

How to Prolong Lithium-based Batteries - Battery University

I also find it odd to say that's "crippling" in a Tesla. It's not for most people on a daily basis unless you have a really long commute. When you need more range, just charge more, rather than keep it at a high state of charge when it's not needed on a daily basis.

However, it really is crippling in a Leaf which is why battery degradation is so much worse in a Leaf. That and the lack of a TMS really hurts the poor Leaf. Still it's a great car for teenage kids to keep them close to home, and for errands around your neighbourhood.