Sheltering in Place - Charge or not

[Rottenapplr]

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.

I set mine 60-70%. You know just in case....

 

[Rottenapplr]

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.

Ya I know I’m gonna go out in a drive to the mountains tomorrow. Mulholland drive. I won’t talk to anyone just go out to the mountain.

 

[smatthew]

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!)

It's reversible, but can be anxiety inducing.

 

[Msjulie]

Don't forget, the battery pack is only able to balance itself if the charge is greater than 85%

I see this a lot (or more often stated as 90%) but I can't recall finding an actual technical link that backs this up - anyone have one? I feel like what I've read is anecdotal but eager to be proven wrong.

 

[vickh]

It's reversible, but can be anxiety inducing.

Agreed, I'm thinking of switching to %, now that I have a good idea what my range is.

It will cut down on range anxiety and envy Will switch to miles if I take a trip

 

[KenC]

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.

In the article they cite, "the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses". There's a long thread somewhere in this forum with alot of technical discussion about batteries with some "experts" chipping in. I think it was shown that 3.92V equates to 63% SOC. So, to avoid cracking and coating of the cathode, and minimize range degradation, the most anal could charge up to that level. Now, that doesn't mean they can't charge up to 80 or 90 or 100, as necessary, but those people who do have a choice and have minimal daily mileage requirements, there's no reason they can't try charging to 60 to 63% SOC.

Okay, I admit I have changed to 61% SOC as my charge limit, purely for research purposes! I'm still showing 310 miles rated range after 15 months and 10,000 miles. Of course, my Model 3 came with zero SOC, home delivered, so I'm a little more concerned about it than the average owner. And, my zero SOC was really zero. The delivery was at a rest stop, since my home is down a small dirt road that the semi could not negotiate in Winter. The driver met me at a rest stop that had no chargers, so I had to push the car back onto the semi, in order to get it loaded to take it to a Supercharger. The driver told me it had zero soc when he loaded it in the morning, 12 hrs earlier. It was a 25F degree day. You can imagine how little charge it had by the time I got it.

As far as I can tell, I've suffered no cell imbalance so far, though I guess charging up to 90% once a month and leaving it there, would force rebalancing if there were any.

 

[vickh]

In the article they cite, "the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses". There's a long thread somewhere in this forum with alot of technical discussion about batteries with some "experts" chipping in. I think it was shown that 3.92V equates to 63% SOC. So, to avoid cracking and coating of the cathode, and minimize range degradation, the most anal could charge up to that level. Now, that doesn't mean they can't charge up to 80 or 90 or 100, as necessary, but those people who do have a choice and have minimal daily mileage requirements, there's no reason they can't try charging to 60 to 63% SOC.

Okay, I admit I have changed to 61% SOC as my charge limit, purely for research purposes! I'm still showing 310 miles rated range after 15 months and 10,000 miles. Of course, my Model 3 came with zero SOC, home delivered, so I'm a little more concerned about it than the average owner. And, my zero SOC was really zero. The delivery was at a rest stop, since my home is down a small dirt road that the semi could not negotiate in Winter. The driver met me at a rest stop that had no chargers, so I had to push the car back onto the semi, in order to get it loaded to take it to a Supercharger. The driver told me it had zero soc when he loaded it in the morning, 12 hrs earlier. It was a 25F degree day. You can imagine how little charge it had by the time I got it.
View attachment 524027
As far as I can tell, I've suffered no cell imbalance so far, though I guess charging up to 90% once a month and leaving it there, would force rebalancing if there were any.

wow! and I was worried b/c I got within 10 miles b/f I understood the low SOC danger, never again. Good to see it didn't do any permanent damage.

I'll try upping to 60%... is that one bar more than 50% on the app?

 

[KenC]

wow! and I was worried b/c I got within 10 miles b/f I understood the low SOC danger, never again. Good to see it didn't do any permanent damage.

I'll try upping to 60%... is that one bar more than 50% on the app?

Dunno, but I would assume so.

 

[Magneto3]

Where is everyone getting the 50% charge info for storage?

Talking to the techs at the nearby Tesla service center, they're all saying just leave it plugged it and charge to 90% (for regular usage).

I can't find any guidance for long-term storage, where is this coming from?

Also, where can I find official guidance on "Rebalancing" the battery? The owner's manual doesnt mention this.

Thanks.

 

[NuttyM3]

wow! and I was worried b/c I got within 10 miles b/f I understood the low SOC danger, never again. Good to see it didn't do any permanent damage.

I'll try upping to 60%... is that one bar more than 50% on the app?

Yes, each one of the bars after 50% is in 10% increments.

 

[KenC]

Where is everyone getting the 50% charge info for storage?

Talking to the techs at the nearby Tesla service center, they're all saying just leave it plugged it and charge to 90% (for regular usage).

I can't find any guidance for long-term storage, where is this coming from?

Also, where can I find official guidance on "Rebalancing" the battery? The owner's manual doesnt mention this.

Thanks.

50% is general rule of thumb for all lithium batteries for long-term "storage". Any SOC choice is a compromise between convenience and longevity. Elon recs 90% for max convenience, but the tradeoff is a little more degradation. For someone like Elon in LA, then 90% is the preferred choice, but each person has their own unique circumstances and should make their own choice.

Rebalancing kicking in at 90% is based upon numerous comments from owners about the advice they get from service centers on why their batteries don't charge up to 100%, etc., and how the battery cells will rebalance if the SOC is set to 90%, for several hours after reaching 90%. Some people report it only works after a couple weeks. Of course, the only way to really know is if you have one of those OBD readers.

 

[Magneto3]

50% is general rule of thumb for all lithium batteries for long-term "storage". Any SOC choice is a compromise between convenience and longevity. Elon recs 90% for max convenience, but the tradeoff is a little more degradation. For someone like Elon in LA, then 90% is the preferred choice, but each person has their own unique circumstances and should make their own choice.

Rebalancing kicking in at 90% is based upon numerous comments from owners about the advice they get from service centers on why their batteries don't charge up to 100%, etc., and how the battery cells will rebalance if the SOC is set to 90%, for several hours after reaching 90%. Some people report it only works after a couple weeks. Of course, the only way to really know is if you have one of those OBD readers.

Thanks for the extra info. I have never charged my battery past 80%. Should I crank it up to 100% before a discharge to 50% just to trigger this? I wish the manual spoke about this. The tech did advise that the predicted range would adjust itself over the first few hundred miles, maybe this is why.

 

[KenC]

Here's the thread with the scientific discussion on batteries:
Battery Degradation Scientifically Explained

 

[KenC]

Thanks for the extra info. I have never charged my battery past 80%. Should I crank it up to 100% before a discharge to 50% just to trigger this? I wish the manual spoke about this. The tech did advise that the predicted range would adjust itself over the first few hundred miles, maybe this is why.

If you are happy with how things are going, then don't change a thing. There's no need to rebalance if your cells are not imbalanced. To me, 80% SOC seems to be the preferred level according to the car, itself, and for most a good compromise between range and convenience.

The "predicted" range isn't your fuel gauge, with the SOC %age or miles remaining. That's not going to change based upon driving style. The "predicted" range based upon your driving style is on your energy chart, using 30miles and Average. Naturally, you have to drive a bit to get an accurate prediction.

 

[RachH]

My question is for those of us who CAN'T charge at home. I live in an apartment and I do not have a plug in my carport. And they won't let me install one, unfortunately, so I have to supercharge regularly. Not ideal in the best of times.

What should I do now?

 

[Msjulie]

@RachH Find a ChargePoint near by?

I though CA had a law requiring you the ability to install a charger (though it may not be cheap or easy)

In CA, Renters Can Now Install Electric-Car Charging Stations

Assembly Bill 2565 would give tenants the right to install an electric-car charging station at their residence, provided the tenant submits a written request to the landlord and pays for the installation costs.

 

[Photo_Frank]

You should just smile with the knowledge that the electrical grid is not threatened and that you don’t have to wait in gas lines with the hoarders.

You also are not exposing yourself to whatever is lurking at the gas pump handle, credit card reader, etc.

 

[jbcarioca]

I had the exact same question and did the research. Set it at 50% and leave it plugged in. It's OK to go out and drive it around for fun and to get the charge down to 50% or lower. If you want to do the research yourself look up how to store lithium ion batteries. Panasonic recommends 30% to 50% charge. No one suggests storing the Tesla at less than 50% charge. Everyone recommends leaving it plugged in.

Mine stays for months at a time, generally 2-3 months. For the last five years I have used the same procedures for my Model S that I do now with my Model 3. I plug the car in after putting on my car cover and leave it at 50%. A day before I return if I expect to take a trip I charge it to whatever level I expect to need. The passive drain seems least at lower levels (not a scientific observation) but anyway a 50% charge is the original 2014 recommendation I received in a message from JB Straubel, so I have never changed. FWIW, my Model S had the same 100% range after 35,000 miles that it did when I took delivery. That's good enough for me.

 

[DR61]

My question is for those of us who CAN'T charge at home. I live in an apartment and I do not have a plug in my carport. And they won't let me install one, unfortunately, so I have to supercharge regularly. Not ideal in the best of times.

What should I do now?

Assuming you are sheltering-in-place: I would find a level 2 charging station near a nice place to take a long walk (with social distancing). Do regularly as necessary to keep battery at 50-90% range (depending on how much charge you want in reserve). Consult Plugshare.com for locations near you.

 

[WdstockWizard]

Why? No need to set to 50%. No valid real data here.

Set it to 50%, plug it in and forget it. If it's above 50%, it'll very slowly burn down, from vampire drain, and recharge when at about 46% or so. Charge it up just prior to needing to drive.

?