70% SOC/charge for "daily" vs. 80%

[Dark-Fx]

100% every charge and you should still be within the degradation warranty after 175k miles. Too many people overthink it IMO.

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[Friscorays]

How do either of those (refuel at home / minimize time fueling in public) address the issue of an unexpected event that would require more than 70% range? I own properties which take 70-80% range for a round trip. If I wake up in the morning and unexpectedly need or want to go then I want to be able to.

I have a functioning charging station in my garage and I like to minimize time spent at public charging stations on the road.

I do this by charging to 80% overnight.

Thought we were talking about best practice principles generally rather than recommended practices for all possible individual circumstances.

Obviously if one might need to cover near or more than 70% of range regularly and does not want to charge someplace other than home, they should pick a charge level that fits their needs.

In our case, round trip commute is 14 miles so 70% is more than enough and we would like to optimize battery life as much as possible with essentially zero downside in our use scenario.

I can't remember any personal emergency ever that would require a drive that would eat up more than 70% of Rivian range but if one were to come up, we would either charge on the way or if a real emergency drive something else......

 

[TipSpa]

Does anyone know why Rivian suggests 70% charge for daily use vs. 80% (which is what I have seen other manufactures recommend). Does Rivian have less buffer in their charging capacities? just seems odd to recommend a "normal daily charge" that is 70% of capacity. I have my R1S set at 80% because that is what I have done with my other EVs... but realized today that Rivian suggests only charging to 70%.

With 7,777 batteries in the vehicle, I think it’s only reasonable to set the daily home charge to 77%, using a 7-hour charging window.

 

[SoCal Rob]

Thought we were talking about best practice principles generally rather than recommended practices for all possible individual circumstances.

Obviously if one might need to cover near or more than 70% of range regularly and does not want to charge someplace other than home, they should pick a charge level that fits their needs.

In our case, round trip commute is 14 miles so 70% is more than enough and we would like to optimize battery life as much as possible with essentially zero downside in our use scenario.

I can't remember any personal emergency ever that would require a drive that would eat up more than 70% of Rivian range but if one were to come up, we would either charge on the way or if a real emergency drive something else......

You were responding to @Goose from https://www.rivianforums.com/forum/threads/70-soc-charge-for-daily-vs-80.16651/post-359079 who raised the issue of an unexpected event as rationale for needing 80%. Your response ignored his concern and I was pointing out that some people’s reality may override best practices. If someone has an elderly parent, kid at school, remote job site etc. that they may need to get to on short notice then they should charge to suit their life. Not yours.

 

[Electrified Outdoors]

I should say that I plug it in whenever its parked at home. The difference in charging to 70% vs 80% I would wager is negligible. Even 90% is considered safe for many other BEV. Its not worth worrying about. I too like to have 80% should I need to make a long trip...though I could probably charge daily to 70% or less and be fine.

Do what is convenient while doing your best to stay out of the top or bottom 10% of the battery and let the BMS do its job.

 

[gregtay]

How do either of those (refuel at home / minimize time fueling in public) address the issue of an unexpected event that would require more than 70% range? I own properties which take 70-80% range for a round trip. If I wake up in the morning and unexpectedly need or want to go then I want to be able to.

I have a functioning charging station in my garage and I like to minimize time spent at public charging stations on the road.

I do this by charging to 80% overnight.

This is exactly it. Does my wife need 80% range every day? No. Certainly not. But, what if she forgets to plug in at night (happens often). What if something unexpected pops up and she is needing to drive much further than often? dumb stuff like... the kids need something for a school project that is due tomorrow (and they procrastinated) and the only store with the thing they need in stock is a long way from home. The EV transition can't be "opps, I would have had the range, but I didn't charge enough last night). With our etron S (~150miles @ 80%SOC) my wife never ran it down to 0 miles around town... but she did come close.

 

[Friscorays]

You were responding to @Goose.....

I sure was.

Specifically this part: "Why fill up a fuel tank if you’re not going to need the full range?"

The answer to that seems self-evident and not particularly controversial: people hate gas stations and want to minimize their valuable time spent there.

The difference between filling up a tank with gas (which does no harm to an engine unless we are going to argue that the increased fuel weight increases engine wear) and charging a battery above a level which is needed (which from my understanding does have actual real-world negative consequences) again seems as obvious as the fact that any individual that is worried that 70% isn't enough should charge to more than 70%.

I am not going to potentially degrade my battery life, no matter by how little, to account for what would at best be at most a once in a decade unexpected rationale for needing more; especially when I still an ICE option.

I should have just left it as this I guess:
Already discussed:
https://www.rivianforums.com/forum/...timize-battery-life-whats-your-strategy.9174/
etc, etc......

 

[SoCal Rob]

I sure was.

Specifically this part: "Why fill up a fuel tank if you’re not going to need the full range?"

The answer to that seems self-evident and not particularly controversial: people hate gas stations and want to minimize their valuable time spent there.

The difference between filling up a tank with gas (which does no harm to an engine unless we are going to argue that the increased fuel weight increases engine wear) and charging a battery above a level which is needed (which from my understanding does have actual real-world negative consequences) again seems as obvious as the fact that any individual that is worried that 70% isn't enough should charge to more than 70%.

I am not going to potentially degrade my battery life, no matter by how little, to account for what would at best be at most a once in a decade unexpected rationale for needing more; especially when I still an ICE option.

I should have just left it as this I guess:
Already discussed:
https://www.rivianforums.com/forum/...timize-battery-life-whats-your-strategy.9174/
etc, etc......

Okay, so in my opinion you’re addressing the gas part and I’m addressing the EV (most relevant) part of @Goose ’s post, “You don’t ever have unexpected events happen?”

My take away is that some people will prioritize battery life above all else and other people will prioritize their own needs and wants over the life of their EV battery. You’re in the former camp and I’m in the latter.

Knowing that they’ll be able to get to the places that their life can reasonably need them is why some folks own a vehicle. I’m not going to be delayed if something comes up which is reasonable to predict in my life just so my Rivian’s battery has an extra few percent of capacity on the day I sell it because I charged to 70% on overnight L2 charging instead of the 80% I needed.

Each of us needs to make our own decisions on these things, but if non-EV people are simply hearing, “You shouldn’t charge anything over 70% daily!” then we aren’t exactly helping EV adoption. I say that because that messaging, (mis)heard, (mis)read, or perceived makes it a bigger problem than it really is if they are still at or under the 85% mid-point of targeted charge setpoints originally specified by Rivian.

edit: phrasing

 

[deadparadise]

Slightly off-topic, but I wish we could set charge limits based on location. We have chargers at work, so I usually charge to 85% every other day (M,W,F) at the office, but sometimes I'll charge at home if I end up driving a lot during the weekend, in which case I only charge to 70%. It doesn't actually take that long to change it through the UI, but it would be nice to set that up automatically.

 

[Goose]

I sure was.

Specifically this part: "Why fill up a fuel tank if you’re not going to need the full range?"

The answer to that seems self-evident and not particularly controversial: people hate gas stations and want to minimize their valuable time spent there.

The difference between filling up a tank with gas (which does no harm to an engine unless we are going to argue that the increased fuel weight increases engine wear) and charging a battery above a level which is needed (which from my understanding does have actual real-world negative consequences) again seems as obvious as the fact that any individual that is worried that 70% isn't enough should charge to more than 70%.

I am not going to potentially degrade my battery life, no matter by how little, to account for what would at best be at most a once in a decade unexpected rationale for needing more; especially when I still an ICE option.

I should have just left it as this I guess:
Already discussed:
https://www.rivianforums.com/forum/...timize-battery-life-whats-your-strategy.9174/
etc, etc......

I wasn't trying to start an argument or be a jerk in anyway. It's hard to convey tone over text.

I'm not trying to get people to charge to 100% every day or anything. I was just saying that in my family I OFTEN have random errands to run, I can imagine others probably are similar. My point is why limit yourself to such low % charge just because your current schedule indicates you do not need it, especially if it's still in the "safe" range? I really doubt any meaningful battery degradation would be experienced charging to 80% over 70% every day.

Here's an example; I met a buddy at a lake recently to go fishing, the lake is 25 miles from my house. I had about 1/3 of tank in my 4Runner, I thought that would be plenty for me to get there and back. Well I'm out at the lake and my wife makes plans to get together with some friends and I should meet them (my wife and daughter) at the friends house. Sounds like fun, thing is, the friends live 30 minutes north of my house and is 20 miles from the lake I was fishing. I had to stop and get fuel on the way, in an EV I would have had to stop for 10-15 min to DCFC (which is a lot more stressful on the battery than 240v charging). Neither of which is a big deal, it's just a random event that changed my plans, and could be the difference in 70% and 80%.

 

[Sevn86]

I charge daily to 80%. I commute a 137 miles round trip for work 5 days out of the week. My mornings start out at 239 mile range and by the time I get home I have between 66-73 miles of range left. I drive mostly highway in all purpose mode with regen and ride height set to standard. Speeds between 75 - 85mph. I don’t think it would be wise for me to charge to 70% as that would freak me out.

Like yesterday on my way to work all lanes closed due do a major accident. I had to reverse off the highway down the exit ramp I passed up just to get around it all.

 

[Fozzymandius]

I think this conversation is hilarious. Obviously no one is telling others to put themselves at risk of being stranded. 137 miles commuting is well outside the norm, so your charging behavior will likely be outside the norm too.

Maybe I'm just lucky but I live in a moderately rural area and even my longest "oops" errand is 20 miles away. We've made do with my wife's C40 that we charge to 80% once every few days when it drops below 30%. Even at 30% I can make it to Costco and back in the dead of winter. My R1S will probably stay at 70% because I should realistically have a few hours warning of needing to drive over 100 miles in a sitting.

Adjust your own life accordingly, no one is saying strand yourself. And if you somehow find yourself doing 100 miles in errands than charge that sucker to 100%

 

[Sevn86]

I think this conversation is hilarious. Obviously no one is telling others to put themselves at risk of being stranded. 137 miles commuting is well outside the norm, so your charging behavior will likely be outside the norm too.

Maybe I'm just lucky but I live in a moderately rural area and even my longest "oops" errand is 20 miles away. We've made do with my wife's C40 that we charge to 80% once every few days when it drops below 30%. Even at 30% I can make it to Costco and back in the dead of winter. My R1S will probably stay at 70% because I should realistically have a few hours warning of needing to drive over 100 miles in a sitting.

Adjust your own life accordingly, no one is saying strand yourself. And if you somehow find yourself doing 100 miles in errands than charge that sucker to 100%

I know it’s not the norm. I just commented on this thread to make a point that I personally wouldn’t feel comfortable charging to 70% with my daily commute. I will continue to charge daily to 80% whether recommended or not. That’s what works for me. There is no right or wrong way. It’s based off your own situation.

Also how many plan to keep their cars past 8 years? With my driving I’ll be at 175k miles in 5.83 years. I typically don’t keep my cars for more than a couple years anyways, so I’m not worried.

 

[Friscorays]

......Also how many plan to keep their cars past 8 years? With my driving I’ll be at 175k miles in 5.83 years. I typically don’t keep my cars for more than a couple years anyways, so I’m not worried.

I don't view cars as disposable items. I'm in my mid 50s and still have every car I've ever purchased besides one which I gave to a family member in need and which was frankly a piece of shit even when new.

My G35 just passed legal drinking age. My wife's daily driver is not far behind and is approaching 200k miles. So for us, preserving battery life as best we can is actually a quite important consideration.

 

[Mark_AZR1T]

You don’t ever have unexpected events happen? Why fill up a fuel tank if you’re not going to need the full range?

Bingo! This is why I fluctuate between 75-80%.

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