Should one charge each night, or only when needed?

[miracj]

I have a friend who only charges his Model Y LR only when it he gets a notification that he needs to charge the car at about 10%, On my Model Y LR, I always charge it to 75% or so every night. I think he should leave it plugged in, to allow for better battery cooling whenever it's needed.

So the question is what are the consequences of each of the charging patterns?

 

[EVEnergy]

The owner's manual states that you should plug in. From what I understand, the wall connection helps the BMS balance the battery pack which should lead (I assume) to better battery life.

 

[ATPMSD]

When it comes to battery health, you may find this graph useful.

 

[El joe]

ABC = Always Be Charging

I plug in every day, but set limits depending on what I need. Usually 80% daily.

 

[ATPMSD]

I rarely charge at home. I burn 15% RT on my commute and charge at the office for free; I set my upper threshold at 80%. I do not charge at home on the weekends unless I am going somewhere as I can normally get back to 80% at the office. Sometimes I go to our second site which burns about 30% RT, in this case I charge when I get home.

 

[MY1stEV]

Battery science aside, the consequences of a pattern of waiting for your car to get down to a low state of charge before recharging puts you at risk of getting caught off guard when you need your car.

When I first got my car I would charge up to 90% and then plug it in again when it got down to 25% or lower (4 or 5 days later). Then one day I had an elderly family member across town get sick. Driving to their home, urgent care, and the hospital was over 75 miles. Had this happened at a point when my car was at a lower state of charge, it would have added additional stress to the whole situation knowing I'd need to get to a supercharger during all this, and there were no superchargers convenient to this route.

Since that day, Boy Scouts motto: be prepared. I charge up every night to 80%

 

[Grovester]

When it comes to battery health, you may find this graph useful.

View attachment 711813

Sorry for being dense but can you explain what the chart means? So anytime below 65% I should charge up to 75%?
thanks.

 

[ATPMSD]

Sorry for being dense but can you explain what the chart means? So anytime below 65% I should charge up to 75%?
thanks.

The graph shows the impact on battery degradation based on various discharge / charge strategies; it does not recommend anything. First and foremost you need to pick a range that works for you. If you can utilize various ranges you can use the chart to determine which one offers the least battery degration.

The vertical line is the maximum capacity the battery will reach. The horizontal line is the number of charge cycles. Let’s look at the 75-45% line, which means the battery is run down to 45% and then charged to 75%. After 1,000 cycles the maximum the battery will charge to is 96%. Another example, if we look at the 100-25% line, after 1,000 cycles the maximum is 90%

Hope this helps.

 

[WADan]

The graph shows the impact on battery degradation based on various discharge / charge strategies; it does not recommend anything. First and foremost you need to pick a range that works for you. If you can utilize various ranges you can use the chart to determine which one offers the least battery degration.

The vertical line is the maximum capacity the battery will reach. The horizontal line is the number of charge cycles. Let’s look at the 75-45% line, which means the battery is run down to 45% and then charged to 75%. After 1,000 cycles the maximum the battery will charge to is 96%. Another example, if we look at the 100-25% line, after 1,000 cycles the maximum is 90%

Hope this helps.

So it would seem that the number of cycles does impact the degradation even though just slightly. Therefore, it would be best to plug in only when the SOC falls close to 40-ish and only charge to 70-ish.

 

[GregW]

For 6 years I charged my 2014 85 S Tesla nightly, usually from 65% to maybe about average of 40%. I dialed down the amperage in the car to charge at 20A. Of course if I knew I was driving further, certain days I'd charge to maybe 80%. After 6 years I only had 4% battery degradation. Was very happy with that. Supercharged perhaps once a month.

 

[Mike_TV]

Tesla states in the Model Y owner's manual on page 158...

"The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it."

They put that part in bold and capital letters for a reason.

 

[45thParallel]

Best battery capacity retention for charging when it goes down to 65% and charging up to 75%. the down side to this is you charge more frequently. The graph for this ends at 8500. Even daily charge will give life of 23 years. Battery capacity retention is a higher priority. That is why Tesla manual recommends daily charging and setting limits for maximum charging unless going for a long trip.

 

[ATPMSD]

So it would seem that the number of cycles does impact the degradation even though just slightly. Therefore, it would be best to plug in only when the SOC falls close to 40-ish and only charge to 70-ish.

Yes, this is what the chart would indicate. But I suggest you also consider the comments made by others. As to Tesla's: "The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it." You may find this of interest:

Should I charge my Tesla every day and night? | Optiwatt

What are the pros and cons of frequent charging? We took a look at all the factors, so you don’t have to, and here is what we found.

getoptiwatt.com

 

[jcanoe]

Best battery capacity retention for charging when it goes down to 65% and charging up to 75%. the down side to this is you charge more frequently. The graph for this ends at 8500. Even daily charge will give life of 23 years. Battery capacity retention is a higher priority. That is why Tesla manual recommends daily charging and setting limits for maximum charging unless going for a long trip.

That may be but I have never owned a vehicle more than 12 years. In 20+ years who knows what will be. The pace of change in automobile technology today is so great that 5 years is like 10 years used to be. I plan to keep my Model Y for ~5 years and then decide whether to replace my 2020 Long Range Model Y.

 

[miracj]

That may be but I have never owned a vehicle more than 12 years. In 20+ years who knows what will be. The pace of change in automobile technology today is so great that 5 years is like 10 years used to be. I plan to keep my Model Y for ~5 years and then decide whether to replace my 2020 Long Range Model Y.

So true,

However, the 1st thing out of the Tesla (and other EVs) haters is how much it is going to cost for a new battery when it goes bad in a couple of years! If the batteries last 500,000 as Tesla says could be instead of the 300,000 miles they have already achieved, at 13,500 miles per year US average, that's 37 years!

What typical ICE engine lasts even 200,000 miles/15 years?

 

[FatherTo1]

So true,

However, the 1st thing out of the Tesla (and other EVs) haters is how much it is going to cost for a new battery when it goes bad in a couple of years! If the batteries last 500,000 as Tesla says could be instead of the 300,000 miles they have already achieved, at 13,500 miles per year US average, that's 37 years!

What typical ICE engine lasts even 200,000 miles/15 years?

Our Model Y sits in the garage alongside my wife’s 16-year-old Lexus ES 330 with 150,000 miles. The Lexus is still smooth and comfortable and feels like it will go another 10 years.

Back to battery charging. I daily-charged our Model S to 90% and it started to lose 7-9 miles of range after six months and 4.5% after the first year, which is supposedly typical. With our Model Y I’ve switched to charging to 70% and only charge it after we use at least 15-20% battery, so once every 2-3 days.

I know it’s not a fair comparison since the S and Y have different battery structures and chemistries, and it may be too early to say, but after six weeks the Y still reflects the same 230 miles of range at 70% with no drop off yet.

 

[thesmokingman]

I charge every few days. We do very short daily trips so the battery lasts a while. Still I try not to let it go too long so at least once a week.

 

[JustJohn]

So true,

However, the 1st thing out of the Tesla (and other EVs) haters is how much it is going to cost for a new battery when it goes bad in a couple of years! If the batteries last 500,000 as Tesla says could be instead of the 300,000 miles they have already achieved, at 13,500 miles per year US average, that's 37 years!

What typical ICE engine lasts even 200,000 miles/15 years?

BMW E46 chassis cars for openers. 200k + is not uncommon.

It's only a comparison, not a contest.

 

[45thParallel]

That may be but I have never owned a vehicle more than 12 years. In 20+ years who knows what will be. The pace of change in automobile technology today is so great that 5 years is like 10 years used to be. I plan to keep my Model Y for ~5 years and then decide whether to replace my 2020 Long Range Model Y.

I agree. I was just interpreting the graphs. I rarely keep a car more than 5 years. Last several cars were passed down to next generation. I might do the same again.

 

[boulder.dude]

When it comes to battery health, you may find this graph useful.

View attachment 711813

Keep in mind this graph (IIRC) is for single battery cells in a laboratory setting.

This is not a graph of actual Teslas.