Sheltering in Place - Charge or not

[hmgolds]

I haven't left my home in 9 days. I just have it plugged in and the charge limit set down to 50%. 50% is still plenty of miles if I need to venture out for food or supplies. I have a HPWC so if I do need to hit the road for whatever reason, I can up the charge limit and top it off pretty quickly.

I can't argue with that for you. But the OP charges on house current (I take that to mean 15a, 120v). And what would concern me (especially for a 75yo in California) is the possible need to drive 100 or even 200 miles to get to a hospital accepting patients. Since there is no material downside to charging to 80%, that's what I would do in his situation.

 

[erb2000]

I can't argue with that for you. But the OP charges on house current (I take that to mean 15a, 120v). And what would concern me (especially for a 75yo in California) is the possible need to drive 100 or even 200 miles to get to a hospital accepting patients. Since there is no material downside to charging to 80%, that's what I would do in his situation.

This is incorrect. See https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
tl;dr: Only charge to 50%.

 

[Zimo]

I am staying at home also but I do enjoy a ride everyday just to have a change of pace if not to see something new or forgotten.

 

[Vancan]

drive your tesla around. You don’t gotta get out the car..

Yup that's what I do: carry Lysol wipes, disinfect all the door handles and elevator buttons you touch going to and from your car, and don't get out of it during your drive. In my case I live alone and am the only driver, so no chance of picking up or passing on anything. And the option to get out and drive is so liberating during this self-isolation time!

 

[Nopantz]

I was charging often 50-80% and my battery was reporting low (~290 mi after about 10K miles). Despite what the manual said, the service center recommend charging 30%-70$ or 20%-80% for better calibration. They had me deep cycle the battery - I ran it down to 7mi and then charged it to 100% to recalibrate it, now maybe I'm 297-299 mi on M3D.

 

[davidg42]

What about turning the car off (Safety and Security > Vehicle Power > POWER OFF)? Does that do anything?

 

[marty143a]

Thanks to all I am 75 also M2P fast car I have ever had love it marty

 

[hmgolds]

This is incorrect. See https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
tl;dr: Only charge to 50%.

Note that I said "material" downside. Show of hands, how many of us only charge to 80%? How many of us would have bought a Tesla if you could only charge to 50% on a regular basis? Further, we don't necessarily know how Tesla's battery management comes into play. While putting a Tesla logo on a battery doesn't change the laws of physics or chemistry, we do know that there are controls in place to prolong life. So 80% as measured and reported by the charging circuit may not be the 4.05v per cell as tested in the article you referenced.

In fact, the article you referenced states "Industrial devices, such as the EV, typically limit the charge to 85% and discharge to 25%, or 60 percent energy usability, to prolong battery life.". Does that mean 100% as reported by the charging app is really 85% of battery voltage? I don't know.

So I don't disagree with your comment that charging to an actual cell level of 50% might be best, I just question whether doing so in our Teslas - as reported by the Tesla charging system - leads to the same benefit. And whether that benefit is significant enough to worry about.

 

[smatthew]

If you only charge to 80% your batteries will become imbalanced over time. The only way to fix this is to leave the car above 85% SOC for days. People who have only been charging to 80% have seen reported capacity drop.

 

[erb2000]

Note that I said "material" downside. Show of hands, how many of us only charge to 80%? How many of us would have bought a Tesla if you could only charge to 50% on a regular basis? Further, we don't necessarily know how Tesla's battery management comes into play. While putting a Tesla logo on a battery doesn't change the laws of physics or chemistry, we do know that there are controls in place to prolong life. So 80% as measured and reported by the charging circuit may not be the 4.05v per cell as tested in the article you referenced.

In fact, the article you referenced states "Industrial devices, such as the EV, typically limit the charge to 85% and discharge to 25%, or 60 percent energy usability, to prolong battery life.". Does that mean 100% as reported by the charging app is really 85% of battery voltage? I don't know.

So I don't disagree with your comment that charging to an actual cell level of 50% might be best, I just question whether doing so in our Teslas - as reported by the Tesla charging system - leads to the same benefit. And whether that benefit is significant enough to worry about.

Thank you for the elaboration and I agree with you. Note that we're talking about storing the car for an indefinite period to time. The generally accepted best practice is to set it to 50% and leave it plugged in. But the advantages of having 80% charge for emergencies or just peace of mind could easily outweigh the minor benefit of 50%.

 

[Regulator]

This is incorrect. See https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
tl;dr: Only charge to 50%.

That is a really old article - 10 years old with some updates.

Based on that article, every 5-7 year old Model S would have enough battery failure to require a warranty replacement.

 

[brucet999]

I am 75 years old and am sheltering in place with no plans to drive for weeks, maybe a month. Should I charge my Model 3 every few nights or just wait until I plan to drive.

How is your electricity billed?

If you are billed on tiered rates, then you can leave it plugged in because it makes no difference when you charge.

If you are billed at time of use (TOU) rates, then you want to plug in at night when rates are low and charge to 80% or so. Let it run down to no less than 50% before charging again to be sure you have enough range for unforeseen eventualities.

 

[Uncle Paul]

Technical people might give you other calculated answers, but I imagine a prudent person, in your circumstances, might just set your charge around 75% and not over think it. Of course, if you are planning a longer outing, perhaps charge up to 90% the night before.

 

[erb2000]

You don't mention the SOC best for long term storage. There are dozens of articles and they all say 30% to 50% actual, with 40% being best. Since actual and displayed are different, you have to guess. 50% is a good guess for the Tesla.

 

[Sans-gas]

I am 75 years old and am sheltering in place with no plans to drive for weeks, maybe a month. Should I charge my Model 3 every few nights or just wait until I plan to drive.

Drive around, enjoy the scenery and sound system and charge it when it’s under 40%. That’s what I’m doing. I avoid contact with people, but enjoy the car too much to stay at home all the time.

I’m still “sheltering in place” but the place is sometimes my M3.

Be safe.

 

[Dondix]

Thanks everyone for this info. I'm heading to the garage to plug in the car.

 

[normd]

I read here that chemistry is chemistry, which is true, but from what I read the chemical com[position of the Tesla battery is different than that of an iPhone. So, how you manage our batteries is different than for an iPhone. Conditioning the battery is important every few months as described above but I am planning on charging when it get below 50% up to 80% for my convenience.

 

[sceptic]

The idea of leaving the car plugged in all the times doesn't work so well for people living in places where they can't do that

 

[Amp Dup]

Here in Southern Cal, the traffic is so much better that going for a ride is actually pleasant! A small silver lining to corona virus.

 

[vickh]

If you only charge to 80% your batteries will become imbalanced over time. The only way to fix this is to leave the car above 85% SOC for days. People who have only been charging to 80% have seen reported capacity drop.

that imbalance is reversible though right?

50% is easy for those of us who don't have long commutes (a lot of people these days!)