I must say that I am not on board with the idea that OCCASIONAL deep discharging is bad for my battery life.
There is a tweet from Elon saying that going to 5% or less is not a problem. More importantly there are many people claiming that deep discharging is bad without any data. Although I admit data is difficult to find, what I do find seems to show that Elon is correct as long as you plug in after deep discharging.
I believe the incorrect information may just be misinterpretation of data. Here is one graph of Dod (depth of discharge) vs life:
Long Cycle Life Lithium Iron Magnesium Phosphate Battery
Although on first glance it appears "obvious" that deep discharging is bad, this doesn't consider that a deeper discharge delivers more energy per cycle. For instance, these Lithium batteries have 15k cycles at 40% Dod and 5k cycles at 80% Dod. So 80% Dod delivers equivalent of 10k cycles at 40% Dod.
I think the takeaway point is that doubling the Dod for any one discharge is similar to using three small discharges instead of two. This is very different than saying even an occasional deep discharge is very bad for your battery.
So if I have a 300 mile range battery that I typically cycle 70%-30% (120 miles), I might expect about 3000 of these cycles for >300k miles of use. If I happen to use a 90% - 10% cycle for a 240 mile trip, I would use three of my 3000 cycles instead of two.
I believe this is important because when we go on a trip that requires 80% of capacity, we need to decide whether to go 100% - 20%, 90% - 10%, or 70% - 30% with a SC stop. I believe that the first two of these choices is significantly better than SC. We know that frequent SC is discouraged and that SC speed is limited by Tesla after ~300 SC to prevent battery damage. (2x/month for 15 years = 300).
So in my opinion it is best to save those few 300 SCs for long trips (> 80% range), deep cycle for moderate range trips, and keep it plugged in to short cycle whenever possible. Most importantly just enjoy our amazing Tesla's!!
There is a tweet from Elon saying that going to 5% or less is not a problem. More importantly there are many people claiming that deep discharging is bad without any data. Although I admit data is difficult to find, what I do find seems to show that Elon is correct as long as you plug in after deep discharging.
I believe the incorrect information may just be misinterpretation of data. Here is one graph of Dod (depth of discharge) vs life:
Long Cycle Life Lithium Iron Magnesium Phosphate Battery
Although on first glance it appears "obvious" that deep discharging is bad, this doesn't consider that a deeper discharge delivers more energy per cycle. For instance, these Lithium batteries have 15k cycles at 40% Dod and 5k cycles at 80% Dod. So 80% Dod delivers equivalent of 10k cycles at 40% Dod.
I think the takeaway point is that doubling the Dod for any one discharge is similar to using three small discharges instead of two. This is very different than saying even an occasional deep discharge is very bad for your battery.
So if I have a 300 mile range battery that I typically cycle 70%-30% (120 miles), I might expect about 3000 of these cycles for >300k miles of use. If I happen to use a 90% - 10% cycle for a 240 mile trip, I would use three of my 3000 cycles instead of two.
I believe this is important because when we go on a trip that requires 80% of capacity, we need to decide whether to go 100% - 20%, 90% - 10%, or 70% - 30% with a SC stop. I believe that the first two of these choices is significantly better than SC. We know that frequent SC is discouraged and that SC speed is limited by Tesla after ~300 SC to prevent battery damage. (2x/month for 15 years = 300).
So in my opinion it is best to save those few 300 SCs for long trips (> 80% range), deep cycle for moderate range trips, and keep it plugged in to short cycle whenever possible. Most importantly just enjoy our amazing Tesla's!!