Is leaving Tesla plugged in while not charging really beneficial?

[heapmaster]

What if you only drive on the weekends for 100-150 miles, still leave it plugged in and charged to 50-55%?

 

[804son]

What if you only drive on the weekends for 100-150 miles, still leave it plugged in and charged to 50-55%?

Sure, leaving the battery sit at a low state of charge is fine. You can leave the battery at lower than 50% as low as you choose really. But there's nothing wrong with leaving it plugged in at a charge level of 50% either. That's what I do, I don't usually leave it sitting at very low states of charge, only because it's a car and it's not usefull if it has no charge.

 

[kavyboy]

What if you only drive on the weekends for 100-150 miles, still leave it plugged in and charged to 50-55%?

I used to do that until one weekend when I wanted to do a spontaneous day trip and didn't have the miles to do a round trip. It kinda kills the spontaneity to sit around waiting for a charge before leaving.

 

[DanDi58]

I used to do that until one weekend when I wanted to do a spontaneous day trip and didn't have the miles to do a round trip. It kinda kills the spontaneity to sit around waiting for a charge before leaving.

Exactly. I don't understand this whole 'leave it at 50%' thing. I mean, Tesla advises to leave it at 90% or lower, so I doubt there is any benefit to leaving it at 50% vs 90% and, as you note, there may be a disadvantage if you have an emergency or just spontaneously decide to drive somewhere beyond a 50% range.

 

[tangible1]

If that's in fact true that AC power is more efficient in maintaining voltage and temp than battery power, that's a great reason to leave it plugged in.

my area is subject to random power outages.
I'm not good with leaving my MYLR plugged in while away for extended periods.
the power fluctuations and their potential impact on the system are unknowns.
I just charge it up and leave it; and check the state of charge once in a while via the APP.
If it were to approach 20% or less, I'll remote the garage door and let my neighbor plug it in. Hasn't been necessary.

 

[jcanoe]

In the spring and summer there are frequent electrical storms. I don't leave my Tesla Model Y or my previous plug-in vehicle plugged in when there is a risk of a storm or when ground strike lightning is within ~5 miles. It it a small risk but why subject the Tesla Model Y to potential damage due to close by lightning strike.

I prefer to keep the battery between 70% and 80% with 60% and 90% being the occasional state of charge. I know that I can add 10% to the battery if needed in 1 hour with my home charging setup. In winter I charge for 90 minutes most days, approximately every other day in spring, summer and fall. These days I rarely charge at home but I can if needed.

I park my Model Y in my garage, I leave the car unlocked with no Sentry mode. After more than 2.5 years the original 12V lead-acid low voltage battery still tests as good.

 

[STS-134]

Exactly. I don't understand this whole 'leave it at 50%' thing.

Calendar degradation is worse when SoC is higher.

I mean, Tesla advises to leave it at 90% or lower, so I doubt there is any benefit to leaving it at 50% vs 90%

There is a HUGE benefit to keeping it at 50% vs 90%. The biggest benefit is going from 90% to 80%. There's a smaller benefit going from 80% to 70% and so on, and you're really getting into diminishing returns when you reduce the SoC from 60% to 50%. But there are still benefits in doing it. Tesla cares about not having to do warranty replacements. And they have a HUGE buffer to work with, as they only replace batteries with more than 30% degradation in less than 8 years/120,000 miles. And the chance that they will have to do this, if you charge to 90% and keep it sitting there, is minimal. So if you are fine with up to 30% degradation in 8 years/120,000 miles, go ahead and charge to 90%. I am not fine with that much degradation, therefore I charge to 50%.

and, as you note, there may be a disadvantage if you have an emergency or just spontaneously decide to drive somewhere beyond a 50% range.

I have never, ever just spontaneously decided to drive more than about 120 miles. And even that only happens about once a year. I easily get most of that even with 50% SoC. And by "spontaneously" I mean decided within an hour or two of departure. In 1-2 hours, I can gain about 15-25% SoC on my 48A EVSE, so I could easily be at 65-75% by departure on even the most spontaneous trip. It's not worth degrading my battery every other day of the year just because I might have to take a spontaneous trip somewhere.

 

[804son]

Calendar degradation is worse when SoC is higher.


There is a HUGE benefit to keeping it at 50% vs 90%. The biggest benefit is going from 90% to 80%. There's a smaller benefit going from 80% to 70% and so on, and you're really getting into diminishing returns when you reduce the SoC from 60% to 50%. But there are still benefits in doing it. Tesla cares about not having to do warranty replacements. And they have a HUGE buffer to work with, as they only replace batteries with more than 30% degradation in less than 8 years/120,000 miles. And the chance that they will have to do this, if you charge to 90% and keep it sitting there, is minimal. So if you are fine with 30% degradation, go ahead and charge to 90%. I am not fine with that much degradation, therefore I charge to 50%.

I have never, ever just spontaneously decided to drive more than about 120 miles. And even that only happens about once a year. I easily get most of that even with 50% SoC. And by "spontaneously" I mean decided within an hour or two of departure. In 1-2 hours, I can gain about 15-25% SoC on my 48A EVSE, so I could easily be at 65-75% by departure on even the most spontaneous trip. It's not worth degrading my battery every other day of the year just because I might have to take a spontaneous trip somewhere.

In my location there are also DC Fast Chargers in every direction from my house, easily within a 50 - 75 mile range. I can reach any of them with <50% battery range. Of course this is location specific and may not be the case for everyone, but it's worth looking to see how much range you really need in the off chance you need to take an immediate long range trip.

 

[STS-134]

In my location there are also DC Fast Chargers in every direction from my house, easily within a 50 - 75 mile range. I can reach any of them with <50% battery range. Of course this is location specific and may not be the case for everyone, but it's worth looking to see how much range you really need in the off chance you need to take an immediate long range trip.

Exactly. Say I do decide to take a spontaneous trip and I need 205 miles of range but only have 180 miles of range in the car and I have zero advance notice, i.e. drop everything and leave and for some reason I don't want to take the PHEV (at this point we're almost info fantasy land as far as concocting a scenario where this makes a difference but whatever)...well I'll get back to within 30 miles of home and then plug in to a DCFC for 3 minutes to get the remaining range to make it back. It's not a big deal and it's much easier on the battery to do this once every 1-2 years than constantly keep it charged up more than necessary.

 

[Rocky_H]

I mean, Tesla advises to leave it at 90% or lower, so I doubt there is any benefit to leaving it at 50% vs 90%

You have to think about the purpose of the advice. What people are discussing here, about using very low states of charge is being stated as for the purpose of preserving the lifetime for as long as possible in an undamaged state. That is the advice you give for artifacts in a museum. A car is not an artifact in a museum. Tesla is having to give advice for people to use the car practically as a car.

So the part about not going over 90% a lot is to avoid the worst, most damaging thing, as @STS-134 mentioned. But Tesla still has to give advice that is balanced for car owners to still practically use the car with enough range, even if there is some gradual degradation--degradation that technically could be avoided but make the car annoying and impractical to use.

 

[GtiMart]

This, exactly this. You can optimize for many variables but you can't optimize them all at the same time. The bunch of nerds we are here optimize life of the battery (and live with the trade-offs), Tesla optimize customer satisfaction with the car (without the battery dropping under 70% capacity during the warranty period)

 

[arichard2401]

I'm in the leave it at 50% camp. But I'm also a weirdo that enjoys being exact about the charge limit so that the car always sits at 50% overnight. I go as far as to set it to charge to 57% and precondition by the time I leave for work, then it sits at work at about 53-ish percent before making it home right around 50% to start the whole thing over the next day.

I think if you want to charge to 90% all the time and aren't really worried about the potential consequences, or not convinced there are any, go for it. Part of what's great about these cars is you can totally nerd out on it, or you can just have it charge up so you're always ready to go and not think too much about it. Do what makes you happy.

 

[father_of_6]

I've been charging to 150%, but after reading the advice from this thread I'm going to drop to 90%.

 

[CaseyL]

I've been charging to 150%, but after reading the advice from this thread I'm going to drop to 90%.

I'm wondering how long it takes to charge to 150% ....

 

[Rocky_H]

I'm wondering how long it takes to charge to 150% ....

"Two weeks"

 

[gt2690b]

I'm wondering how long it takes to charge to 150% ....

Only a couple seconds of explosive fire should get you there

 

[zoomer0056]

I've been charging to 150%, but after reading the advice from this thread I'm going to drop to 90%.

Your range is 50% better too ... almost.

 

[DanDi58]

You have to think about the purpose of the advice. What people are discussing here, about using very low states of charge is being stated as for the purpose of preserving the lifetime for as long as possible in an undamaged state. That is the advice you give for artifacts in a museum. A car is not an artifact in a museum. Tesla is having to give advice for people to use the car practically as a car.

So the part about not going over 90% a lot is to avoid the worst, most damaging thing, as @STS-134 mentioned. But Tesla still has to give advice that is balanced for car owners to still practically use the car with enough range, even if there is some gradual degradation--degradation that technically could be avoided but make the car annoying and impractical to use.

I see your point. I use my MY as a real car - I take it through a car wash when it's dirty (heavens!), I typically keep it charged to 85% or 90% in case of emergency (elderly parents live 3 hours away) - I have even had bags of mulch in the back. I'm not too worried about degradation as that won't affect my around-town driving and minimally affect my road trips.

 

[STS-134]

I see your point. I use my MY as a real car - I take it through a car wash when it's dirty (heavens!), I typically keep it charged to 85% or 90% in case of emergency (elderly parents live 3 hours away) - I have even had bags of mulch in the back. I'm not too worried about degradation as that won't affect my around-town driving and minimally affect my road trips.

I mean, I use my M3 as a real car too. I'm not afraid to charge all the way to 100% if I really need to (like the time I drove all the way to Walnut Grove and back without charging and I needed about 91-95% of the battery to do so, or before any road trip where I'll need to charge along the way). That's definitely not something you'd do with any museum artifact. However, when I charge above 50%, I do so in a manner that minimizes battery degradation (set charge limit to what I need to get to my destination and set departure time to 1 hour before I intend to leave) because there's no point in making the car less useful more quickly than it has to happen if it's not necessary. But the way I see it, I paid for a larger battery and there's no point in actually paying for it if I'm never going to use it.

 

[Rocky_H]

I balance those conditions in some ways. I have my limit set to around 70 or 80 % I think. But then I go a few days before plugging in again, where it's getting down to a bit less than half full, so it's not staying near 70 or 80 % most of the time.