Rivian R1T charging curve test 20-80% [by TFL]

[SeaGeo]

They don't actually allow charging to 100%. The 100% mark on your display is chosen by the engineers to correspond to a particular voltage but that voltage can be set arbitrarily.

No shit AJ. We all realize that. The 100% everyone is referring to is the max charge allowed by the software. Which is there for a use case similar to what @branden has described.

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[branden]

They don't actually allow charging to 100%. The 100% mark on your display is chosen by the engineers to correspond to a particular voltage but that voltage can be set arbitrarily. Rivian has done lots of cycle testing on their batteries (back in the early days most of their promotional stuff emphasized that). Their batteries, like everyone elses, show an inverse relationship between level of charge and number of cycles before a certain level of degradation is reached. That curve is monotonic. But of course neither you nor I or our resident expert knows what that curve looks like exactly but Rivian has probably got a pretty good idea. Their goal is to chose a voltage to assign to 100% and there are several factors to consider. They obviously want it to be as big as possible to maximize range at the same time they want it to be small enough that only a very small number of owners will show up with warranty claims for battery degradation. They can reduce that number by discouraging charging to high SoC.

The best analogy I can think of is skin cancer. If you go out in tropical sun once in a while you probably won't get it. But if you run around the tropic of Capricorn in shorts and a singlet every day you will achieve the highest skin cancer rate in the world (as the Aussies have done). Another important thing to understand is that this is very much a random thing. There are other factors at play (European Aussies are by and large of Northern European descent - the TLOs don't get it).

You can't change the battery chemistry in the car you own. The facts are that the higher and faster you charge the less your EXPECTED battery longevity. It is really up to you to decide the level of "risk" you want to accept. Perhaps you don't care a whit if your range goes down to 80% after 5 years. Perhaps you don't plan to keep the car that long. Perhaps you feel you are a lucky guy and can run rough and get away with it. But everyone should understand that the rougher he treats his battery the faster it will degrade.

The other point is that there is absolutely no benefit to leaving the house at high SoC in most cases as the SCs are now pretty dense. There was a day when that wasn't true but it's past. Yes, it may sometimes be necessary and in that case, Rivian and Tesla give you the option of charging to the mark. But it's pretty clear they prefer that you don't. You'd be wise to take their advice.

You might technically be correct, but on EVs with advanced BMS and thermal management (Tesla, Lucid, Rivian, etc) - like you said, 100% isn’t truly 100%. If anything, Tesla is quite aggressive in allowing cells to reach 4.2V and even with my practically worse case scenario usage (1000x DCFC sessions in 2 years, 100% almost daily), there was no accelerated degradation compared to a nearly identical car with mostly AC charging. Both were at about 13% degradation at 200k miles. That’s perfectly acceptable.
DCFC density is not the point - charging to 100% overnight on L2 charging when you’re not waiting for your car is more time efficient for a travel day.
Don’t let the battery sit at low or high extreme SoC (under 15%, over 90%) for extended periods and drive the damn thing. Drive more, worry less.

 

[ajdelange]

I will take Branden’s experience which mirrors mine and many other high mileage EV owners over what you seem to be trying to push on everyone.

Have at it. It's your battery after all.

What I am trying to push is called "common sense" but it is clearly mislabeled as I find it quite rare. Now this common sense is based on engineering perspective. I don't expect the average reader here to be sophisticated enough to understand that "Bullshit - my Uncle Louis had one he charged hard every day and after 5 years his battery was only degraded 2%" is meaningless becuase yes, that can happen just as my uncle Harry smoked 3 packs a day and died ot 97 at the hand of an enraged husband doesn't mean that it's OK to smoke 3 packs a day. This gets into the statistica nature of the thing,

The recommendation to not charge to 100% is there for warranty purposes of battery longevity.

Someone with common sense would be able to use that information to make his decision.

If that is a concern it is actually better to charge the car to 100% on level 2 vs having to charge more on level 3 DCFC.

You obviously know, or think you know, something about batteries that I don't.

 

[ajdelange]

No shit AJ. We all realize that. The 100% everyone is referring to is the max charge allowed by the software. Which is there for a use case similar to what @branden has described.

I give up. I think I'll go explain it to my wife.

 

[branden]

Have at it. It's your battery after all.

What I am trying to push is called "common sense" but it is clearly mislabeled as I find it quite rare. Now this common sense is based on engineering perspective. I don't expect the average reader here to be sophisticated enough to understand that "Bullshit - my Uncle Louis had one he charged hard every day and after 5 years his battery was only degraded 2%" is meaningless becuase yes, that can happen just as my uncle Harry smoked 3 packs a day and died ot 97 at the hand of an enraged husband doesn't mean that it's OK to smoke 3 packs a day. This gets into the statistica nature of the thing,

Someone with common sense would be able to use that information to make his decision.

You obviously know, or think you know, something about batteries that I don't.

The common sense approach is to drive more, worry less and use the preset charge limits (with both Tesla and Rivian labeling 100% as “Trip”). The cars are smarter than you give them credit for and if you had to be an EE to maintain battery life on an EV, we’d be seeing Tesla battery failures left and right, but we’re not.

 

[SeaGeo]

I give up. I think I'll go explain it to my wife.

Just take 5 minutes to actually listen to and think about the context that people are talking about rather than assuming everyone except you is a moron. What context would make you think that Branden or myself are referring to the theoretical capacity of the battery and not the software defined limit when we are referring to charging it to 100%?

 

[Joints4Sale]

Have at it. It's your battery after all.

What I am trying to push is called "common sense" but it is clearly mislabeled as I find it quite rare. Now this common sense is based on engineering perspective. I don't expect the average reader here to be sophisticated enough to understand that "Bullshit - my Uncle Louis had one he charged hard every day and after 5 years his battery was only degraded 2%" is meaningless becuase yes, that can happen just as my uncle Harry smoked 3 packs a day and died ot 97 at the hand of an enraged husband doesn't mean that it's OK to smoke 3 packs a day. This gets into the statistica nature of the thing,

Someone with common sense would be able to use that information to make his decision.

You obviously know, or think you know, something about batteries that I don't.

I don’t know a lot about current batteries.

I do know what has been recommended by five different car manufacturers that I have had the fortune of owning. They are also concerned about warranty claims as much as they are the user experience.

For my use case, I don’t keep cars long enough to worry about battery degradation.

 

[Trandall]

Don't think AJ is purporting to know proprietary info. I think he made some safe assumptions.
I am curious if the statement about charging to 100% briefly is better than fast charging for degredation. Seems it would depend on battery chemistry and even cell construction. Can anyone cite examples of where this is coming from? Or is it anecdotal from personal experience, not that personal experience can't have value.

 

[ajdelange]

What context would make you think that Branden or myself are referring to the theoretical capacity of the battery and not the software defined limit when we are referring to charging it to 100%?

None which is why I didn't think that. The discussion of what 100% means was part of my attempt to explain to you guys how things work at which attempt I am obviously failing miserably.

When this happens I tend to get snarky so let me apologize for that and exit the discussion.

 

[COdogman]

Is it also possible now that BEVs from multiple manufacturers have several years out there on the roads for "regular" use, that manufacturers are just now discovering the limits and true durability of their batteries? My assumption is they started out with a cautious approach and made recommendations to customers based on that. Now they have years of real data to go off of and possibly have relaxed those recommendations somewhat with regards to real world charging behavior and how it affects the battery life? I understand there is a big difference between hard science and anecdotal evidence, but we don't necessarily get to see all the data these manufacturers collect.

I don't know this to be true - the R1T will be my first true BEV (we had a Volt for years but I don't count that). Just a thought...

 

[Attesan997]

Is it also possible now that BEVs from multiple manufacturers have several years out there on the roads for "regular" use, that manufacturers are just now discovering the limits and true durability of their batteries? My assumption is they started out with a cautious approach and made recommendations to customers based on that. Now they have years of real data to go off of and possibly have relaxed those recommendations somewhat with regards to real world charging behavior and how it affects the battery life? I understand there is a big difference between hard science and anecdotal evidence, but we don't necessarily get to see all the data these manufacturers collect.

I don't know this to be true - the R1T will be my first true BEV (we had a Volt for years but I don't count that). Just a thought...

BMW has done this with the new series of BEV vehicles. From what I remember on OOS Kyle mentioned the daily charge recommendation was in the 90s and it was based on BMW internal data gathered by customers.

 

[SeaGeo]

https://www.instagram.com/r1t_of_ma/p/CXqpgNLOAfZ/?utm_medium=copy_link

I had forgotten about this post, but here's a screenshot of an R1T pulling the max speed from a 150kw charger ( 171kw on this one ?) at 31%. Just another datapoint suggesting an unfortunate charger or software limitation for the TFL guys.

 

[branden]

https://www.instagram.com/r1t_of_ma/p/CXqpgNLOAfZ/?utm_medium=copy_link

I had forgotten about this post, but here's a screenshot of an R1T pulling the max speed from a 150kw charger ( 171kw on this one ?) at 31%. Just another datapoint suggesting an unfortunate charger or software limitation for the TFL guys.

Most EA 150kW stations are actually 175kW

 

[SeaGeo]

Most EA 150kW stations are actually 175kW

Yep! That's why I had asked Tommy if he could try a 150kw charger. ?

 

[acacia1602]

I appreciate the feedback (i’ve seen lots of it on this forum) and say what you want but we DO have tons of experience in towing and off-road environments.

On our rocky mountain towing test quickest rate was 150kW as well from 15%.

If you can make your data available via Google sheets that would be amazing. Doing so unlocks analysis from the community. Really like your channel BTW.

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