Rivian is doing itself a disservice by not publishing a charging curve

fbitz777

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I don't know but for example on my old '17 Tesla X I use SOC+CHARGE_RATE=110KW

Most batterie start with high charge rate and end up close to L2 levels when full.

And yes outside 'cold" temperature (with cold battery) can lower the initial charge rate; that's why Tesla will precondition the battery before you arrive at supercharger. And cold for a Tesla is 60F!
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The reason they don't is because there isn't one. The vehicle manages the charge rate taper according to the conditions that pertain during the particular charging session based on SoC, temperatures etc. As the battery becomes fuller the charge rate will taper.
Sure there is. At least for most manufacturers, there is a backbone curve that a car will not exceed in reasonably ideal conditions.

There are a few cars I can think of that have unique curves that are either preprogrammed for time (Mach e) somewhat regardless of where you plug in within a range of SOCs, and some the shape of the curve for and individal session will drop off the backbone curve because of thermal limitations (ioniq5 seems to be this way, as does Lucid). However, if you plug a warm car in at an ambient temp of say... 75F, most car models will generate a fairly consistent curve between charges and cars.

And to your point that plugging in at different SOC is going to have the car behave differently. And the degree to which that occurs varies *a lot* between make and model. The EQS has a significantly different charging curve than the Etron GT or the Mach e, or the Model S.
 
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I don't know but for example on my old '17 Tesla X I use SOC+CHARGE_RATE=110KW

Most batterie start with high charge rate and end up close to L2 levels when full.

And yes outside 'cold" temperature (with cold battery) can lower the initial charge rate; that's why Tesla will precondition the battery before you arrive at supercharger. And cold for a Tesla is 60F!
That's an interesting little formula you have for you X! Definitely wouldn't work for a etron though. Granred the etron just sits at ~150kw until 80 or 85% or whatever. Lol.
 

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That's an interesting little formula you have for you X! Definitely wouldn't work for a etron though. Granred the etron just sits at ~150kw until 80 or 85% or whatever. Lol.
yes but Etron has a built in reserve at the top end so they can afford to be more aggressive
 
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yes but Etron has a built in reserve at the top end so they can afford to be more aggressive
Oh, I know. Just noting the difference. I'm kind of expecting the R1T to be similar to the EQS curve. But at the same time I've heard from a couple of owners thst it's holding 150kw+ up to around 80 to 85%. I haven't actually seen it though, so who knows how reliable their memories are.
 

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Charging curve is not some click bait topic, but rather, it is the most important fact BEV owners need to understand and educate themselves about charging instead of focusing on peak charging rate.
BEVs rarely achieve its peaking charging rate and when it did, it would be under ideal conditions (warm temperature, A perfect BMS, fully functioning DCFC, preconditioned/warmed battery), and that too for a brief period of its charging time.

Here are two videos that highlight the importance of charging curve VS peak charging rate.

1. Here is one with the eTron charging test at -10C.
This video shows how the eTron can maintain a flat 150KW rate all the way up to 80%,
Audi E-Tron 55 10-80% SOC Charging Speed & Time Test! - YouTube

2. Here is one where the charging rate of 4 EVs are compared (eTron Gt, Taycan, eTron 55 and Model 3).
You can see despite two vehicles having an 800V system (eTron GT and Taycan), the eTron 55 which has a flatter charging curve finished first to 90%.
Audi e-tron GT charging on 350 kW Ionity - YouTube

If anyone wants to learn about charging curve and charging rates, I highly recommend watching these two YT channels along with Inside EVs charging test videos to understand charging curves.



.
 

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Sure there is. At least for most manufacturers, there is a backbone curve that a car will not exceed in reasonably ideal conditions.
Yes, there is an envelope (what you call a "backbone curve") out side of which the BMS will not venture but where it goes withing the constraints of the envelope can be quite variable. That's why it's called an "envelope" - it bounds the set of possible charging curves.
 

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I like Bjorns for the EQS. It's just an interesting comparison between it and a couple of other reference cars (like the E-tron GT).

Kris' is a good example of the curve for it when the battery is relatively cold as well, as he noted. I'd really like it more manufacturers started showing battery temp to the driver.

That being said, combining this with Bjorn's curve is a good example of the "standard curve." Once the battery warmed up for Kris, it's basically the same curve as what Bjorn logged. Give or take a few kw.
 
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ajdelange

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Charging curve is not some click bait topic, but rather, it is the most important fact BEV owners need to understand and educate themselves about charging instead of focusing on peak charging rate.
BEVs rarely achieve its peaking charging rate
Since there really isn't a standard "charging curve" that applies to any given vehicle the charging curve envelope isn't that important. If one plays with the actually observed "charging curves" obtained from a car he is likely to find that the BMS is actually shooting for a fixed overall charge rate. At least that appears to be the case from the data I have looked at. As I mentioned in an earlier post for my Tesla X it's a bit more than 1.0C. Newer models seem to be shooting for 1.2 - 1.4C. We needen't concern ourselves about actual Rivian profiles (though they may be interesting). What we need to know is the number that goes in front of C.
 
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Yes, there is an envelope (what you call a "backbone curve") out side of which the BMS will not venture but where it goes withing the constraints of the envelope can be quite variable. That's why it's called an "envelope" - it bounds the set of possible charging curves.
And some cars run along that envelope routinely (for example, the ID.4 is very consistent with a warm battery). Some cars have to drop off based on various factors. In both cases, knowing what a reasonable representative curve is when plugged in low is useful. If the car doesn't follow the envelope when plugged in at a low SOC for various reasons (like managing heat), then it obviously takes more data to set expectations. I suspect the Lucid is like this personally, but we'll see with some more data.
 
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Since there really isn't a standard "charging curve" that applies to any given vehicle the charging curve envelope isn't that important. If one plays with the actually observed "charging curves" obtained from a car he is likely to find that the BMS is actually shooting for a fixed overall charge rate. At least that appears to be the case from the data I have looked at. As I mentioned in an earlier post for my Tesla X it's a bit more than 1.0C. Newer models seem to be shooting for 1.2 - 1.4C. We needen't concern ourselves about actual Rivian profiles (though they may be interesting). What we need to know is the number that goes in front of C.
Sorry, but you're wrong. That's true with some cars, but not all. Below is an example of the ID.4 curve. When warm, it very consistently follows this no matter what SOC you plug in. It's just a scaled up shape of the ID.3 curve (smaller battery) for c-rate. I've plugged in at several different SOC and it almost always follows it exactly (temperature issues aside).
https://insideevs.com/news/495561/volkswagen-id4-dc-fast-charging-consistency-amazes/

https://insideevs.com/news/492606/volkswagen-id4-82kwh-dc-fast-charging-analysis/

Will the BMS manage it lower if conditions don't allow the car to hit full charging speeds? Yes, but there are a good number of cars where the car reliably follows the envelope that the manufacturer programs into their BMS.

Editing again: you can also see this with the Taycan and e-tron GT. Assuming they talk to the charger correctly.
 

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Since there really isn't a standard "charging curve" that applies to any given vehicle the charging curve envelope isn't that important. If one plays with the actually observed "charging curves" obtained from a car he is likely to find that the BMS is actually shooting for a fixed overall charge rate. At least that appears to be the case from the data I have looked at. As I mentioned in an earlier post for my Tesla X it's a bit more than 1.0C. Newer models seem to be shooting for 1.2 - 1.4C. We needen't concern ourselves about actual Rivian profiles (though they may be interesting). What we need to know is the number that goes in front of C.
There absolutely is a standard charging curve. It's based off of the cell design. Manufacturers of the cells release the specifications that need to be followed.
 

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A timely post:
"We’ve done 900+ miles, IL, Iowa, Nebraska and this morning Colorado. We haven’t had a problem finding chargers. Walmart/Electrify America are all along the route. This is the first EVgo we’ve used and we are pulling 172 kw right now."
 
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A timely post:
"We’ve done 900+ miles, IL, Iowa, Nebraska and this morning Colorado. We haven’t had a problem finding chargers. Walmart/Electrify America are all along the route. This is the first EVgo we’ve used and we are pulling 172 kw right now."
They were the one that pulled 185 yesterday, but also had their charging limit set to 100%. So it said time to charge was 1 hour and 12 minutes to finish charging from 20%. Which, as most of us no, you'll almost never do. But at the same time, most people don't know that they have it set to charge to 100%, and think it's very slow charging.

Another employee pulled 191 kw peak on a road trip from, I believe, Normal to CA. He said he thought it was pulling more than 150kw up to around 80%.

edit: I wonder if that's a 200kw charger, or a 350kw charger from EVGO.
 
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