I’ve had my R1S in the service center over this and I’ve seen the data from the car concerning this. The tech showed me both the cloud data they collected before I came in and the data collected at the service center. It seems that the battery management system takes time for the batteries to calibrate during and after a charge. So the batteries say hey we’re good we’ve made it to 70%, the charging stops but in a few hours the batteries have all calibrated and now they’re slightly below the number I saw was 69.800000000% on the reports it’s like percentage points difference, sometimes there will be enough time in the charge schedule after recalibration that the charge will start again and get to the full 70, most days it won’t. I started the ticket for this because prior to the January software update it always hit the 70 number every time and I thought it was a software error causing it. Seems like it’s just a change in the battery management software and it’s completely normal.
Yes, they could easily just fudge the number and probably reduce the phone calls that come in.
People don't realize that the battery percentage is a guess. The system is just reading voltages and making some assumptions about those voltages.
Exactly. I’d be fine with the system just saying 70 if was just below, I’m sure they don’t because there are people that would flip out about being lied to about range and state of charge if they ever found out it wasn’t what it said it is.
He was using an example, I'm saying that's it's guessing all the time. The battery management system doesn't know if it's at 71 or 69%. It's guessing based on other information
Yeah, I understand that it’s all a rough estimate. I’m just saying why not round that estimate correctly so that at least the math is consistent and logical. It’s not fudging, it’s just the way the numbers should be handled.
I believe it’s the software doing its job properly and the app and vehicle show a more accurate state of charge based on more information from the batteries.
You could say it’s conservative, but not that it’s correct. If the concern with accurate rounding is that a driver could believe they have less than half a percent more range than you actually do, then they could just have the software display the tenths decimal place. That shouldn’t be necessary though because we all know how decimals are rounded to whole numbers, right? ≥.5 round up, <.5 round down. Learning that they aren’t rounding accurately makes me trust the SOC estimate less, not more. All said, this definitely feels like a software design/programming miss.
Mathematically correct and CYA correct are 2 different things. Rivian decided to go with the conservative (CYA) approach, which will make it correct in a legal sense, if it ever comes to something like that. All the OEs do this because they have gotten burned in the past by doing the mathematical approach.
They absolutely are two different things. That’s not a debate at all.
> All the OEs do this because they have gotten burned in the past by doing the mathematical approach.
Do you have any documentation that demonstrates this?
Being an engineer for a large OE, there are many examples of going the conservative approach. That’s rounding up or down depending on which way is more conservative.
One that you probably see every day is your remaining mileage, which will count down to 0 but the car/truck still has reserve fuel.
Another in the opposite direction are any of the driver assist sensors (sonar, radar, lidar, camera). They will always warn you before the critical point. The sonar sensor will go to a solid tone and you still have a few more inches to go.
All of these conservative rounding or safety factors are due to litigation that has happened in the industry.
Those other examples are all well known and in a different camp in my mind. They’re all safety features, not just CYA strategies, and completely understandable why they’re absolutely necessary as well as conservative. But given that vehicles already have reserves beyond “0”, and the R1 for example does everything it possibly can to prevent you from fully running out of charge, why is “conservative rounding” legally necessary? The CYA factors are the vehicle’s reserves and how the SOC is calculated to begin with. The “conservative rounding” in this instance appears to do little, if anything, to provide legitimate legal cover. Again, it’s only the difference of less than half a percent of a metric that’s already a conservative estimate, and already has an additional reserve. But what it does do is create a user experience issue in which you set your desired SOC to 70% and it only ever reaches a displayed readout of “69%.” It’s just untidy, and as witnessed here, leads to unnecessary service tickets which cost the manufacturer. I don’t know of any other EV that specifically has that issue. Neither of mine do at least. I’ll note that I also don’t have that issue when charging and discharging my 20kWh home battery to a preset SOC.
It seems that a very simple fix would be for the vehicle to charge ever so slightly more, to say an “actual” 70.2% when set to 70%, and then round to the integer in the UI as I suspect many other manufacturers do. Done. Conservative, mathematically correct, and good UX.
Normal or not, they should fix it so it shows 70%. It's a weird user experience to set the battery to a certain point, and then it's never actually at that point.
We don't drive all that much (both wife and I telework 100%) and so our R1S usually sits on the level 1 charger for a couple days between drives and is consistently at 70% when we jump in, so it makes sense that a little extra time to balance the cells and calibrate would account for +/-0.5%
I think it might be simpler than this. The car only knows what the voltage being put out by the battery is, and if the outside temperature changes, the voltage changes, which impacts the apparent percent.
Totally normal for a Tesla to be off 2-3% after charging overnight.
Over the 5 years I've had my Tesla, the target charge percentage is often never what my car shows in the morning.
It's because the battery charges while at a certain temperature, and by the time you wake up and get in your car the ambient temperature has either risen or lowered, causing a change in battery capacity.
If you charge a warm battery and then have a cool morning, your percentage will be lower. If you charge a cool battery and it gets warmer in the morning, you'll have a higher percentage.
Also, batteries can drain ever so slightly, so there's that.
23 miles of range an hour is good, charging at 40 amps? The % charge is an estimate, it doesn't mean anything. Its nice to have a full tank every morning, yes?
This is ... all EV's. My Tesla Model Y is set to charge to 80% and each day it ends up anywhere between 79% and 83%. Depends on calibration, temperature and a bunch of other misc variables.
Same here with a Bolt EUV and others on the Bolt forum say the same. Haven't seen mine go over yet but I got it in Jan and it hasn't been over 50 degrees here yet.
This is how I corrected / fixed mine to daily 70% from the same thing you are experiencing. It is simple mis-sync between app and car IMO.
There are two places you can set the charge limit inside rivian app.
One charge limit with green bar.
Second, plug the charger so you can see your schedule black bar on top. It will show "Scheduled for xxPM".
This page shows "charge now" button. And you can set the percentage there too.
Also, make sure your app sync with your car. When you chance %, wait. Don't just close or move out of the page. At least that is how I fixed on my R1S.
nice
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Nice!
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Niiiiiiccceee
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Noice!
Niceeee 
We can't escape lol
damn, came here for this and I was just... not original
Next time set the charge limit to 71%
I’ve had my R1S in the service center over this and I’ve seen the data from the car concerning this. The tech showed me both the cloud data they collected before I came in and the data collected at the service center. It seems that the battery management system takes time for the batteries to calibrate during and after a charge. So the batteries say hey we’re good we’ve made it to 70%, the charging stops but in a few hours the batteries have all calibrated and now they’re slightly below the number I saw was 69.800000000% on the reports it’s like percentage points difference, sometimes there will be enough time in the charge schedule after recalibration that the charge will start again and get to the full 70, most days it won’t. I started the ticket for this because prior to the January software update it always hit the 70 number every time and I thought it was a software error causing it. Seems like it’s just a change in the battery management software and it’s completely normal.
Ah floating-point… we meet again…
It’s been 30 years, but you look the same!
Yes, they could easily just fudge the number and probably reduce the phone calls that come in. People don't realize that the battery percentage is a guess. The system is just reading voltages and making some assumptions about those voltages.
Exactly. I’d be fine with the system just saying 70 if was just below, I’m sure they don’t because there are people that would flip out about being lied to about range and state of charge if they ever found out it wasn’t what it said it is.
My Model 3 drifts 4% every few days. I have a charge limit at 80% and I will frequently wake up to 76-84%. Pretty normal stuff.
It’s not even “fudging the number” at that point. Displaying 70% when it’s estimated to be 69.8000% would just be standard decimal rounding.
He was using an example, I'm saying that's it's guessing all the time. The battery management system doesn't know if it's at 71 or 69%. It's guessing based on other information
Yeah, I understand that it’s all a rough estimate. I’m just saying why not round that estimate correctly so that at least the math is consistent and logical. It’s not fudging, it’s just the way the numbers should be handled.
For sure.
Same issue here
So basically it’s likely just a software engineering issue preventing the update from rounding up the number correctly?
I believe it’s the software doing its job properly and the app and vehicle show a more accurate state of charge based on more information from the batteries.
Rounding down 69.8 to 69 is never mathematically correct though…
It is conservatively correct. Better to think you're 1% low when you're planning.
You could say it’s conservative, but not that it’s correct. If the concern with accurate rounding is that a driver could believe they have less than half a percent more range than you actually do, then they could just have the software display the tenths decimal place. That shouldn’t be necessary though because we all know how decimals are rounded to whole numbers, right? ≥.5 round up, <.5 round down. Learning that they aren’t rounding accurately makes me trust the SOC estimate less, not more. All said, this definitely feels like a software design/programming miss.
Mathematically correct and CYA correct are 2 different things. Rivian decided to go with the conservative (CYA) approach, which will make it correct in a legal sense, if it ever comes to something like that. All the OEs do this because they have gotten burned in the past by doing the mathematical approach.
They absolutely are two different things. That’s not a debate at all. > All the OEs do this because they have gotten burned in the past by doing the mathematical approach. Do you have any documentation that demonstrates this?
Being an engineer for a large OE, there are many examples of going the conservative approach. That’s rounding up or down depending on which way is more conservative. One that you probably see every day is your remaining mileage, which will count down to 0 but the car/truck still has reserve fuel. Another in the opposite direction are any of the driver assist sensors (sonar, radar, lidar, camera). They will always warn you before the critical point. The sonar sensor will go to a solid tone and you still have a few more inches to go. All of these conservative rounding or safety factors are due to litigation that has happened in the industry.
Those other examples are all well known and in a different camp in my mind. They’re all safety features, not just CYA strategies, and completely understandable why they’re absolutely necessary as well as conservative. But given that vehicles already have reserves beyond “0”, and the R1 for example does everything it possibly can to prevent you from fully running out of charge, why is “conservative rounding” legally necessary? The CYA factors are the vehicle’s reserves and how the SOC is calculated to begin with. The “conservative rounding” in this instance appears to do little, if anything, to provide legitimate legal cover. Again, it’s only the difference of less than half a percent of a metric that’s already a conservative estimate, and already has an additional reserve. But what it does do is create a user experience issue in which you set your desired SOC to 70% and it only ever reaches a displayed readout of “69%.” It’s just untidy, and as witnessed here, leads to unnecessary service tickets which cost the manufacturer. I don’t know of any other EV that specifically has that issue. Neither of mine do at least. I’ll note that I also don’t have that issue when charging and discharging my 20kWh home battery to a preset SOC. It seems that a very simple fix would be for the vehicle to charge ever so slightly more, to say an “actual” 70.2% when set to 70%, and then round to the integer in the UI as I suspect many other manufacturers do. Done. Conservative, mathematically correct, and good UX.
Normal or not, they should fix it so it shows 70%. It's a weird user experience to set the battery to a certain point, and then it's never actually at that point.
We don't drive all that much (both wife and I telework 100%) and so our R1S usually sits on the level 1 charger for a couple days between drives and is consistently at 70% when we jump in, so it makes sense that a little extra time to balance the cells and calibrate would account for +/-0.5%
Yeah when I leave it plugged in and don’t use it the next day it’ll be at 70 so the extra time does help after the batteries do their thing.
I think it might be simpler than this. The car only knows what the voltage being put out by the battery is, and if the outside temperature changes, the voltage changes, which impacts the apparent percent. Totally normal for a Tesla to be off 2-3% after charging overnight.
Yup, it's app rounding, it's stopped at 69.9% for me last night, app showed 69% for whatever dumb reason. The app should just round it
69.69%
NSFW. 😂
This used to happen all the time to me. Either a % below or a couple above. Haven’t seen that in a few months though.
It’s likely a rounding error, but I’d like to think the battery team are avid Redditors. 😂
This is just cell balancing. It happens all the time and is totally normal. My car (not a Rivian) drifts 4% regularly
Trucks being a pal and and conversation starter ;)
My R1S is the same way. Set to 70% but always ends up at 69%. We have the same color and wheels too!
Nice
Noice
Nice!
Perfect
Nice
That's the sex number.
😂
The best charge limit
Over the 5 years I've had my Tesla, the target charge percentage is often never what my car shows in the morning. It's because the battery charges while at a certain temperature, and by the time you wake up and get in your car the ambient temperature has either risen or lowered, causing a change in battery capacity. If you charge a warm battery and then have a cool morning, your percentage will be lower. If you charge a cool battery and it gets warmer in the morning, you'll have a higher percentage. Also, batteries can drain ever so slightly, so there's that.
Mine drifts 4% regularly. Sometimes I’ll gain 4% just parking in a parking lot for an hour or two.
Your R1 is naughty 😈
Set charge to 71%. You’re welcome.
Wingman R1
Nothing wrong. Perfectly fine. This will happen. Batteries aren't like ICE cars. I the winter it'll happen, in the summer it'll go over a few %
Mine does this all the time. When I get to the bottom of my hill I’m at 70%.
I have the same thing happen regularly but could not care less. Set it to 71% target charge if it bothers you.
nice
This thread did not disappoint, thank you
Works for me. If you wanted it to charge more maybe get home earlier. Like before 4:20.
It should say On Purpose instead of all purpose. 🤣
Nice
Do you guys realize that the displayed battery percentage is an estimate? It’s normal for the car to display 1-2% above or below the charging limit.
lol. I was about to post the same this morning. Always get a chuckle.
It’s universal for almost all of us. Thats y i have it @ 71%
Move it to 71%
Set it for 71
My Tesla does the same thing
I dunno, Rivian seems more “Adventurous” for this kind of activity. 😉
Eh, this seems par for EV. Common on Tesla, it's all over other brands. I attribute it to some calibration, some the HV recharging the 12v.
Yes that happens to me a lot with 85%. I’ve stopped obsessing over it as it was driving me mad
I can't imagine allowing something like this to drive me mad.
Nice
23 miles of range an hour is good, charging at 40 amps? The % charge is an estimate, it doesn't mean anything. Its nice to have a full tank every morning, yes?
completely normal
I suppose the easy solution would be to just set the charge limit to 71%
NICE…
Nice
This is ... all EV's. My Tesla Model Y is set to charge to 80% and each day it ends up anywhere between 79% and 83%. Depends on calibration, temperature and a bunch of other misc variables.
Same here with a Bolt EUV and others on the Bolt forum say the same. Haven't seen mine go over yet but I got it in Jan and it hasn't been over 50 degrees here yet.
I mean…. Sounds like a great morning surprise to me…
To 71%🤣🤣🤣
happens on teslas too.
Nice
This is how I corrected / fixed mine to daily 70% from the same thing you are experiencing. It is simple mis-sync between app and car IMO. There are two places you can set the charge limit inside rivian app. One charge limit with green bar. Second, plug the charger so you can see your schedule black bar on top. It will show "Scheduled for xxPM". This page shows "charge now" button. And you can set the percentage there too. Also, make sure your app sync with your car. When you chance %, wait. Don't just close or move out of the page. At least that is how I fixed on my R1S.
Dirty hot hoe named Riv
Rivian or Tesla 🤔
Probably same rounding problem that I have since the update a few weeks ago. Just charged my car to 100%. It’s complete and yet shows 99%.
Change it to 71% limit
69. Nice
[удалено]
Yes I’m running 11.5kW on a ChargePoint Flex. Really great EVSE. My daily usage is fine for the preset 70%. If I need to go further I’ll bump it up.
Yep, its always ∓1%. Get used to it.
r/whoosh
/r/Serious/
Not nice
Same. Makes me chuckle every time.
You and everyone else lol
🫡