A question about supercharging, full charging, and and battery health.

[Abstracter]

I have been wondering about the optimal way for me to charge my battery when going on long trips.

Scenario one: Slow charge to 100% before trip. start at 100%. Drive all the way, battery ends up at 10%.

Scenario two: start at 80%. Drive until battery at 40%. Supercharged to 70%. Drive until 20%.

The point is that both scenarios require 90% battery use. The problem is that both A: super charging And B: charging to 100% (or going below 20%) put some additional strain on the battery (it’s been stated from multiple sources, including from your Elon Musk himself).

The question is. Which one of these two scenarios is best for the battery in the long run, if I had to choose one as my daily routine?

This might be a extremely esoteric question, but I agonize over these kind of silly little things!

 

[Tam]

...The point is that both scenarios require 90% battery use...

I think you answered the question already. I would choose scenario 2: 80 - 40%, then 70% - 20%

 

[Veritas1980]

If this is daily driving I would take scenario 3:
Charge to 90% from start, supercharge somewhere between 50-20% to 70-80%.

Not for daily long trips but occasionally long trips, charge to 100% just before driving and aim for 10-20% at the supercharger (edit: or destination charger).

You really need to supercharge a lot before you get restricted charging speed (also depends on battery type), and all data so far does not point to excessive degradation of the battery.
People have been charging to 100% regularly and seen no significant degradation, as long as they don't overdo it.

What I wouldn't do, is keeping the battery at extended amount of time above 90% and below 20%.

 

[fmonera]

Simplifying a bit, batteries swell when they are charged and deflate when discharged. Big gaps is what degrades the battery most.

The smallest the gap, the better for the battery. If you were able to charge from 50% to 60% (+10%) nine times during your 90% travel, that would be even much better for battery health.

 

[Abstracter]

Thanks for good inputs! I wonder what that min-max battery longevity is, if you where to compare Supercharging from 0-100% every time. Vs Always staying between 40% and 70%, with trickle charge...

 

[Veritas1980]

Thanks for good inputs! I wonder what that min-max battery longevity is, if you where to compare Supercharging from 0-100% every time. Vs Always staying between 40% and 70%, with trickle charge...

You will for sure have more degradation on the 0-100% supercharging, batteries don't like extreme state of charge and heat (generated by fast charging).
But it also needs to be practical, which is why we have the BMS in the car. And so far, it seems to do a great job of keeping the packs healthy, even in extreme temperatures and with high charge rates.

 

[Shock-On-T]

Definitely start long trips with 100%.
It's better to arrive at a supercharger with 30% than 20%, if you need 50% to reach destination. You won't need to wait at supercharger as long.
For daily driving, keep it around the 50-60% mark (eg 80 down to 30, up to 70, down to 20, up to 80 ...)

 

[ewoodrick]

You really need to supercharge a lot before you get restricted charging speed (also depends on battery type), and all data so far does not point to excessive degradation of the battery..

FYI, the Model 3 pops up a nag reminder if Supercharging at 10% for more than a few days.
Not sure of the exact details, but I got the pop-up last week after being on the road for a few days.

 

[ewoodrick]

I have been wondering about the optimal way for me to charge my battery when going on long trips.

Scenario one: Slow charge to 100% before trip. start at 100%. Drive all the way, battery ends up at 10%.

Scenario two: start at 80%. Drive until battery at 40%. Supercharged to 70%. Drive until 20%.

First, stop thinking so much about the battery. In general things will often work themselves out the way they should be.

When going on long trips, think about the passengers as much as the battery. Also, think about the next segment that you have to drive as well.

If you use #1, then you are coasting in on a empty battery, what are you going to do next? If it is the morning leg, then do you just want to rest for an hour at the Supercharger? If it is an evening leg, then are you pulling up to a hotel empty? What about charging for tomorrow?

For a morning leg, choose a scenario that gets you to a point that makes it easy for lunch. Why wait for an hour at 10AM at a Supercharger and then drive for another hour and stop to eat lunch when you can stop and do bothat the same time?

When you listen to only the onboard routing and charge for only X minutes at each charger, generally you will arrive at your destination with only 10-20%. Don't you want to drive around after you get there? I always recommend adding more than the map tells you to.

For a singular, 270 mile trip where you have a charger at your destination, just use scenario 1. But for other distances, get smart about the tip, use the battery as you need to. Don't worry about it.