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PappaBolt

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Apologies if this has been covered. I'm curious about everyone's charging strategy to optimize battery life. We are given the option to charge to 70%, 85%, 100% with the nudge to NOT charge to 100% unless needed. I'm curious about daily/weekly driving and charging habits. If average daily/weekly use is within the 70% range, it makes sense to stay in that range when charging. But is it better to let the battery (vampire) drain and charge less frequently, or is it better to "trickle" charge to always keep it topped up to 70%?
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Smithery

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Practice from Tesla ownership, with a 5 year old 100D that still has just above 90% original battery capacity, that we're carrying forward to R1T:
Keep your charge between 20% and 80%, and L2 charge unless you absolutely have to L3 charge.

With 80% not an option, we leave ours set at 85% but cut it off remotely based on the estimate when we plugged in.

L1 charging is *technically better* for the battery even than L2, at a purely theoretical level. But:
- Probably no change to battery health in practice
- L1 charging is less efficient than L2 WRT energy waste.
 

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I plug in daily for 70%. Thursday night I go to 85% to account for weekend trips. I only charge to 100% if I need the full range.

There is a long warranty on the battery, so I could care less if there is damage. Plus, I'm sure my R1T will be with another owner in 5 years (or less).
 

CharonPDX

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In general, it is best for a Lithium Ion battery to be "as close to 50% full as much as possible."

So in theory, if your daily commute used 10% of your vehicle's battery each way, the "best" solution would be to charge to 55% at home, drop to 45% when you get to work, charge at work to 55%, so that you get back home at 45% again.

But real world usability concerns pop up, so generally you don't do that. :p

If your usual daily use is such that charging to 70% each night, you won't drop below 30%, then 70% would be the "best" for battery longevity. If you occasionally need to drive further, and know ahead of time, just charge to 85% for that day. If you don't know in advance, just charge to 85%, it'll be fine.


Only charge to 100% if you are taking a long trip, and either you will *NEED* that full 100% to reach a charger, or 100% will let you reach your destination where you can L2 charge; when 85% wouldn't let you reach it. Otherwise, charge to 85% and rapid charge along the way.

Note that it's *sitting* at close-to-full or close-to-empty that is bad. So if you are going to charge to 100%, use the departure timer to have it reach 100% immediately before you leave. if you're leaving Sunday afternoon, don't plug in Friday evening and set to 100% and leave it sitting at 100% all day Saturday.

But realistically, modern battery management systems are good. Set it to 70 or 85 as makes sense for your usual use, 100% when you really need it, and don't worry about it.
 

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It'd be nice to be able to just set charge level directly as opposed to 3 buttons. If I go away for a while I'd rather just leave it set to charge to 30-40% which is technically better.
 

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In general, it is best for a Lithium Ion battery to be "as close to 50% full as much as possible."

So in theory, if your daily commute used 10% of your vehicle's battery each way, the "best" solution would be to charge to 55% at home, drop to 45% when you get to work, charge at work to 55%, so that you get back home at 45% again.

But real world usability concerns pop up, so generally you don't do that. :p

If your usual daily use is such that charging to 70% each night, you won't drop below 30%, then 70% would be the "best" for battery longevity. If you occasionally need to drive further, and know ahead of time, just charge to 85% for that day. If you don't know in advance, just charge to 85%, it'll be fine.


Only charge to 100% if you are taking a long trip, and either you will *NEED* that full 100% to reach a charger, or 100% will let you reach your destination where you can L2 charge; when 85% wouldn't let you reach it. Otherwise, charge to 85% and rapid charge along the way.

Note that it's *sitting* at close-to-full or close-to-empty that is bad. So if you are going to charge to 100%, use the departure timer to have it reach 100% immediately before you leave. if you're leaving Sunday afternoon, don't plug in Friday evening and set to 100% and leave it sitting at 100% all day Saturday.

But realistically, modern battery management systems are good. Set it to 70 or 85 as makes sense for your usual use, 100% when you really need it, and don't worry about it.
This!!!!!
 

Blueassassin

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what's the low that matters? i go down to about 20% or more then charge to 70% I only charge like once a week. is that too low? I did notice the other day it starts cutting full power away once you are below 25%
 
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PappaBolt

PappaBolt

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In general, it is best for a Lithium Ion battery to be "as close to 50% full as much as possible."

So in theory, if your daily commute used 10% of your vehicle's battery each way, the "best" solution would be to charge to 55% at home, drop to 45% when you get to work, charge at work to 55%, so that you get back home at 45% again.

But real world usability concerns pop up, so generally you don't do that. :p

If your usual daily use is such that charging to 70% each night, you won't drop below 30%, then 70% would be the "best" for battery longevity. If you occasionally need to drive further, and know ahead of time, just charge to 85% for that day. If you don't know in advance, just charge to 85%, it'll be fine.


Only charge to 100% if you are taking a long trip, and either you will *NEED* that full 100% to reach a charger, or 100% will let you reach your destination where you can L2 charge; when 85% wouldn't let you reach it. Otherwise, charge to 85% and rapid charge along the way.

Note that it's *sitting* at close-to-full or close-to-empty that is bad. So if you are going to charge to 100%, use the departure timer to have it reach 100% immediately before you leave. if you're leaving Sunday afternoon, don't plug in Friday evening and set to 100% and leave it sitting at 100% all day Saturday.

But realistically, modern battery management systems are good. Set it to 70 or 85 as makes sense for your usual use, 100% when you really need it, and don't worry about it.
Something new for us to obsess about :rolleyes:: The battery goldilocks zone (45%-55%)
 

CharonPDX

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Something new for us to obsess about :rolleyes:: The battery goldilocks zone (45%-55%)
Yeah, I don't bother. I do 70%. Mostly because I plan on keeping this truck for at least a decade, so want to minimize wear; but don't care enough to try to keep it in "the goldilocks zone".
 

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A battery engineer coworker of mine who previously worked for one of the big EV-producing OEMs religiously plugs his EV in to allow the BMS to do everything it wants to do to optimize battery health. I think a lot of the guidance from actual battery engineers is to do just that.

I think trusting the BMS (and the guidance from the manufacturer to keep 'er easy, and use 70% when you can) is your best bet. Trusting people on the internet is probably not the right call. Even trusting people on the internet who claim to be EEs (like me!) is probably not a good idea. Electrical Engineering is a broad discipline. Battery science is a complicated thing (and only partially overlapping with EE). Trust the people who are paid six figure salaries to optimize the performance and lifetime of the battery.

And I'm some random guy on the internet. So don't listen to me either.
 

atebit

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Trusting people on the internet is probably not the right call.
.
.
.
And I'm some random guy on the internet. So don't listen to me either.
Uh oh…

Stack Ovęrf owe§₩
[root]#
 

Prime

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Ive always tried to maintain charge between 20% and 80% on my Tesla, unless we were road tripping and required some L3 charging. Is there any info if Rivian will allow for finer adjustments in the charge limit vs the 70, 85, 100?
 

evguy

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Apologies if this has been covered. I'm curious about everyone's charging strategy to optimize battery life. We are given the option to charge to 70%, 85%, 100% with the nudge to NOT charge to 100% unless needed. I'm curious about daily/weekly driving and charging habits. If average daily/weekly use is within the 70% range, it makes sense to stay in that range when charging. But is it better to let the battery (vampire) drain and charge less frequently, or is it better to "trickle" charge to always keep it topped up to 70%?
We cap it at 70% for daily driving and plug it in every night (L2 charger, 48A), regardless of what the state of charge is at the end of the day. That way, we always have 200+ miles of (nominal) range to start the day (we're on the 20" AT's). The only time we'll charge to 100% is when we're leaving for a long road trip (which is usually once every 2-3 months).
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