Actual risk to charge everyday at 100%?

[sakabaro]

I wonder what's the expected risks, battery degradation, and extra costs for charging at 100% almost everyday?

The Cybetruck is my first Tesla, and I am trying to wrap around battery charging decision tradeoffs. I like the idea of having it 100% ready whenever for a long back-and-forth trip and to not have to plan around home charging or superchargers. Like later today, I may have to do 2-3h round trip after some driving for the day, or maybe not depending on a few things. But, my Cybetruck has a warning to discard when you keep charging it at 100% a few times which made me reconsider my current setup.

From my understanding and my Google-ing, it's mostly to preserve battery life, the lithium-ion batteries are expected to degrade 10% in 3 years if you do 100% instead of 5% if you do 20-80%.

Also, the extra electricity costs seem to be around $1-2 to charge from 80% to 100%.

If my numbers are correct and you okay with both the extra costs for charging and the faster battery degradation, why not doing this? It's hard to find actual graph, estimations, and actual IRL battery degradations online to make a more informed decision.

I am also in Texas. Which get super hot; 100-110F for several months is common. I am worried if there are risks of the battery expanding like phone ones if left outside, charged at 100%, when super hot.

Thanks for the inputs!

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[scohen2002]

It was explained to me when I got my model 3 in 2019 that the battery could charge 1000 times to 100% or 10,000 times to 80% before degradation of performance. I don’t know how accurate this was but I almost never go all the way to 100%.

 

[tmeyer3]

Charging to 100% isn't the problem, leaving it at 100% while not driving is.
In short:
You're holding a lot of potential chemical energy around the cathode of the battery. It WANTS to oxidize and move toward the anode. The higher the state of charge, the greater the "pull". Leaving it at max state of charge will accelerate the physical deformation from this "pull" of the anode material towards the cathode material, called dendrites. The longer dendrites gets, the less power it can store. If the dendrites reach the cathode, that cell is effectively shorted.
Tesla batteries are highly resistant to dendrite formation, but no rechargeable battery chemistry is immune.

 

[sakabaro]

Is there a way to quantify that pull between a 80% and a 100% charge? Is it just around 20% worse or like exponentially worse?

The thing that is confusing is that we never have to worry about this for laptops and phones. Despite being the same lithium-ion technology. You charge it up to 100% and accept the battery degradation.

 

[Travis64]

Is there a way to quantify that pull between a 80% and a 100% charge? Is it just around 20% worse or like exponentially worse?

The thing that is confusing is that we never have to worry about this for laptops and phones. Despite being the same lithium-ion technology. You charge it up to 100% and accept the battery degradation.

My iPhone 15 max charges to 80%

not worth going over if you need more go to a supercharger for 5mins

 

[sakabaro]

I think something might be wrong with your iphone. My Iphone 15 is still at 100% battery health despite driving from 100% to 10% almost every day.

The thing is not 5 minutes at the supercharger. More like a good 20min to go from 80% to 100% and you still have to drive there back and forth like 10min. So minimum 40min before you can start a long trip.

 

[Travis64]

I think something might be wrong with your iphone. My Iphone 15 is still at 100% battery health despite driving from 100% to 10% almost every day.

The thing is not 5 minutes at the supercharger. More like a good 20min to go from 80% to 100% and you still have to drive there back and forth like 10min. So minimum 40min before you can start a long trip.

5mins at 0%

 

[chaosmarine92]

Is there a way to quantify that pull between a 80% and a 100% charge? Is it just around 20% worse or like exponentially worse?

The thing that is confusing is that we never have to worry about this for laptops and phones. Despite being the same lithium-ion technology. You charge it up to 100% and accept the battery degradation.

You do have to worry about it but most people replace their device after a year or two before the degradation gets really noticeable. Because of that the manufacturers haven't bothered to allow stopping charging at 80%. My last phone I kept for 3 years and charged it to 100% every night. The last 6 months I had it it was very noticable that the battery didn't last as long and got a lot hotter under use.

 

[Obie_fl]

I think you may be over thinking it. Unless you have a lot of the unexpected long trips just charge to 80%. If you know you you are going to need more battery the next day you can program the truck to charge in the middle of the night to go to 100% just don't leave it sit. Usage of the Supercharger would not be for topping off but to get you back home which could take any where from 5 to 30 minutes unless you run really low.

I've had much worse battery degradation on my various laptops, phones and iPads then either of my Tesla's. Range anxiety is a thing but you will adjust pretty quickly.

 

[MyFirstElectricTesla]

I was thinking about posting a thread about charging but this one is similar.

My understanding is batteries are limited to re-charge times. Let's say:

- Batteries are limited to 1,000 times of charging.
- 100% would drive 100 miles.

By the end of life of the batteries:

- If you charge 0% - 100% after 1,000 charging times you would get 100,000 miles.
- If you charge 20% - 80% you would have only 60,000 miles.

So you've driven a little over half of mileage if you charge 20 - 80, why not 0 - 100 have almost double mileage before changing a new batteries pack?

Just my $0.0000002.

 

[tmeyer3]

Is there a way to quantify that pull between a 80% and a 100% charge? Is it just around 20% worse or like exponentially worse?

The thing that is confusing is that we never have to worry about this for laptops and phones. Despite being the same lithium-ion technology. You charge it up to 100% and accept the battery degradation.

The expected life of these devices, or a replacement battery, is significantly shorter and cheaper. No one bothers, but it's still happening.

 

[chaosmarine92]

I was thinking about posting a thread about charging but this one is similar.

My understanding is batteries are limited to re-charge times. Let's say:

- Batteries are limited to 1,000 times of charging.
- 100% would drive 100 miles.

By the end of life of the batteries:

- If you charge 0% - 100% after 1,000 charging times you would get 100,000 miles.
- If you charge 20% - 80% you would have only 60,000 miles.

So you've driven a little over half of mileage if you charge 20 - 80, why not 0 - 100 have almost double mileage before changing a new batteries pack?

Just my $0.0000002.

That's not how the math works out. It's more that going 0-100% is one cycle, but going 20-80% is 0.6 cycles. But it's worse than that because as you approach either 0% or 100% each percent change effectively is more than 0.01 cycles. So going 80% to 81% is like 0.01 cycles but going 99% to 100% is like .02 cycles. Obviously these numbers are made up but that is the trend.

 

[Obie_fl]

I was thinking about posting a thread about charging but this one is similar.

My understanding is batteries are limited to re-charge times. Let's say:

- Batteries are limited to 1,000 times of charging.
- 100% would drive 100 miles.

By the end of life of the batteries:

- If you charge 0% - 100% after 1,000 charging times you would get 100,000 miles.
- If you charge 20% - 80% you would have only 60,000 miles.

So you've driven a little over half of mileage if you charge 20 - 80, why not 0 - 100 have almost double mileage before changing a new batteries pack?

Just my $0.0000002.

Nice math but not true. It is 100 times per full cycle charges. The 20% to 80% is only 60% of a full recycle charge so the math cancels out but you don't get the degradation that tmeyer3 explained above.

Typed too slow David beat me to it.

 

[Fleetwood75]

Meh. I split the difference and I charge to 90% every night at home

 

[GatorCyber]

Batteries do not like to be at 100%, unless they are LFP. Don't do it unless absolutely necessary. Set your limit to 80% and plug in every night.
There is a chart from a study done on degradation based on max charge %. Google Jeff Dahn, who Tesla hires for battery chemistry research. There are lots of articles and videos discussing these topice.
Keep your daily charge limited to 80%-90%. 70% is even better. Keeping your battery close to 50% at all times is best.
I would only go to 100% if absolutely necessary (round trip with no SuC), and don't let it sit at 100%, charge it and go.
Also keeping your truck outside in a hot desert climate will degrade your battery.

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