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

[Hopper]

Curious. How many times a year do you guys drive more than 250 miles in a day?

About 20 times, plus any road trips taken that tear.

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[ajdelange]

Wow. That is one way to make a simple math problem much too complex and with less accuracy.

As I said it is exquisitely simple and certainly as accurate as what you propose as it is the same. As I also said the innumerate aren't going to be able to grasp it but you don't have to be a Ramanujan to be able to.

Adding a 10% fudge factor plus a few percent here and there is a lot of wiggle room.

The accuracy depends on how well you are able to estimate the required English to be applied to your basic consumption. Both my X and the R1T require about .33 % per mile (rated). If I'm in terra incognita I just use that in determining how much charge to add. If my next leg is on a stretch of road where I know consumption is .36% per mile I use that. The ability to estimate this English comes with experience.

We also have to think about "meaningless precision". If I have 25% at arrival, a 180 mile leg ahead of me and would like to have 20% at destination then I know without even thinking about it that I will need to add about 180/3 - 5 = 55%. If, in fact, driving conditions on that piece of highway require 0.36% rather than .33% per mile then I should add an additional 5%. If I fail to do so I will arrive with 15% SoC. Do I care? That's well within my comfort zone. Note: I do care when I am playing mental games to see how close I can hit an estimate to pass the miles away but practically speaking 20 ± 5% is plenty good for me.

With my formula, we arrive at the next charger within a few miles of our target range every time.

I'm not trying to convince you to switch over. Continue to do what you like. I'm just trying to point out that there are simpler ways that don't require any formulas or calculators and that give results of more than sufficient accuracy. One doesn't really care about how many estimated miles one has at destination. What he cares about is destination SoC i.e. how much reserve is in the tank. Since with the Rivian a percent is about 3 miles it's pretty trivial to translate 15 percent reserve inot 45 miles. I encourage people to stop using miles as a proxy for state of charge and set vehicle displays to %. But I don't tell them they should or must do that because I know that while this is clearly the "natural" way to do it for techies that it isn't for the math phobic.

 

[ajdelange]

Start the day with 100% charge from charging overnight, pull into DCFC with 5-10%, charge to ~70% and get back on the road and repeat is generally ideal for EV road trips.

Er, no. One starts from home using the same philosophy he uses between chargers. Charge to the level required to get to the first charging stop with comfortable margin. Now if that happens to require going over 80% so be it and to do it from time to time is OK.

I'm speaking in terms of battery management here. As it costs me about 2¢ per mile to charge at home and nothing to charge at an SC one might think my strategy would be to add the minimum charge at home but let's not be too silly.

 

[ajdelange]

Curious. How many times a year do you guys drive more than 250 miles in a day?

At least 4 and probably 10.

Although I agree with your point, I don't want to spend 40 minutes at a charger on the days I do. At least from this video I know I can expect to.

Well 250 miles is 80% of the R1T Large battery and as the OEMS seem to like to charge their batteries at around 1C you can expect that it will take 80% of an hour (48 min) to take on that much charge. Charging rates are, of course, trending up as charging rate appears to be overtaking range as the parameter on which OEMs compete. Assuming a rate of 1.2C taking on 80% charge is going to require 2/3 hr.

This is one of the advantages of the Max pack that isn't at first obvious to many. 250 miles is only 61% of the Max Pack battery and thus can be loaded in 36 min at 1C.

This assumes, of course, that chargers supporting 1C are available. For the Large that's 135 kW but for the Max it's 180 kW.

 

[R1S Maineiac]

Well, let’s see. The Rivian is

• Better for the environment
• Better visibility
• Better storage
• Better power
• Better traction
• Better seats
• Better interior
• Better aerodynamics
• Better flexibility for on-road/off-road
• Better cost per mile

But take the outback if you prefer!

The interior of the R1S will be bigger than any Outback. As someone who has done VA to MA, or VA to ME round-trip, for over 25 years now....from the days when it was me, alone in a Neon, till now, when it's me, the wife, the toddler, and 2 dogs.........space is king.

 

[branden]

Er, no. One starts from home using the same philosophy he uses between chargers. Charge to the level required to get to the first charging stop with comfortable margin. Now if that happens to require going over 80% so be it and to do it from time to time is OK.

I'm speaking in terms of battery management here. As it costs me about 2¢ per mile to charge at home and nothing to charge at an SC one might think my strategy would be to add the minimum charge at home but let's not be too silly.

I've done over 100k miles in EVs just in the last 2 years - there is no reason to start with any less charge at the beginning of the day. Leg 1 of a travel day is to go to the farthest DCFC I can, and then generally hopping between the next DCFCs.

 

[R1S Maineiac]

No CCS (or any non-Tesla) vehicle can use Superchargers outside 10 stations in The Netherlands.

Part of the requirement to get money from the Feds from the infrastructure package (and yes, Tesla is applying for that money), is that your charging network is not a "walled garden".

They'll be opened soon. There may be time limits, definitely a different pricing scale, and maybe only certain locations, but there will be non-Teslas charging at Superchargers by the end of 2022.

 

[branden]

Part of the requirement to get money from the Feds from the infrastructure package (and yes, Tesla is applying for that money), is that your charging network is not a "walled garden".

They'll be opened soon. There may be time limits, definitely a different pricing scale, and maybe only certain locations, but there will be non-Teslas charging at Superchargers by the end of 2022.

I hope that's the case, but I'm incredibly skeptical until it happens.

 

[ajdelange]

I've done over 100k miles in EVs just in the last 2 years - there is no reason to start with any less charge at the beginning of the day.

There is and everyone seems to be aware of it except you. it's documented in the Owner's manuals. Please stop assuming you are smarter than Elon and RJ.

 

[ajdelange]

I wonder if they is a battery life "tax" to be paid for these quick charging times? I know it's a balancing act but I don't understand all the ins and outs.

Yes, there is which some of our self appointed experts here don't seem to appreciate. Tesla's manuals direct owners to avoid fast DC charging to the extent possible and Rivian clearly advocates charging to the lowest practicable level in daily use.

At the same time Tesla, and the other OEMs pus for faster charging times. There is "breaking news" today that Tesla V3 SC are being upgraded 324 kW later this year. That may be more furphy than news at this point but the implications are interesting. That's a 3.24C charge rate for a 100 kWh battery (of course that's a peak rate which would not be sustained). Also, assuming the load line slope of the vehicles stay the same that implies that the V3s will deliver 774A (they are currently limited to 600) at 537V to a 385 V battery!

The further implication is that Tesla will be putting vehicles on the road that will accept that level of charge. Or perhaps not - maybe it is in order to be able to serve Lucid and Hummer, Or perhaps the reason the CT is taking so long is that it will have 800V architecture.

 

[SeaGeo]

There is and everyone seems to be aware of it except you. it's documented in the Owner's manuals. Please stop assuming you are smarter than Elon and RJ.

There's also three predefined charging limits listed in the owner's manual. If Rivian was concerned about infrequently charging to 100% for a short period of time significantly damaging the battery they wouldn't provide the option.

 

[branden]

There is and everyone seems to be aware of it except you. it's documented in the Owner's manuals. Please stop assuming you are smarter than Elon and RJ.

I’m not saying to charge to 100% everyday - I’m saying to charge to 100% on road trips. There’s a big difference.
I’m not saying that I’m smarter than Elon and RJ, but their recommendations are also to reduce warranty claims. Having owned 2 ~200k Tesla Model S, one with over 35MWh DCFC and one with under 10MWh DCFC, there was no difference in degradation.

 

[ajdelange]

There's also three predefined charging limits listed in the owner's manual. If Rivian was concerned about infrequently charging to 100% for a short period of time significantly damaging the battery they wouldn't provide the option.

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.

 

[Joints4Sale]

There is and everyone seems to be aware of it except you. it's documented in the Owner's manuals. Please stop assuming you are smarter than Elon and RJ.

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.

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

 

[Joints4Sale]

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.

You seem to have proprietary information about what Rivian has done. Which is strange, since they don’t seem to share a lot of info about their batteries.

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