So Why Does It Matter Keeping Tesla Battery Between 20%-80% Charged?

[Singuy]

I am seeing many people not charging to 100% and draining down to zero. Most are recommending charging at 20% and maxing it out at 80% to prevent battery degradation.

So people are using 60% of the battery from day 1...but every metric I've looked at takes a Tesla battery to degrade down to 60% after 20-30 years.

So why artificially degrade your battery down to 60% on day one in fear that in 30 years..it'll may actually degrade down to 60%? So the payback period starts after 30 years. Everyone keeping their Tesla for 30 years here?

 

[TLej]

Because shallow charging centered around 50% means when you need the other 40%, it’s there to use. If you were to actually degrade your battery by frequently charging to 100%, you lose that capacity for good.

If you actually need/use the range daily, going 90/10 doesn’t hurt things. From what I’ve read, it is only keeping the battery at a high (or low) SOC for extended periods that causes damage. Honestly, I usually cycle from 80 - 30 or 40 and it doesn’t seem to have affected my battery much. It’s not a big deal when an overnight charge at home gives you a full “tank” the next day anyhow.

 

[ewoodrick]

The batteries don't like the following

• Sitting at 100% for long times
• Going to 0%
• Charging at the highest rate possible every time

So people try to stay away from these situations.

The concept of the battery going to 60% after 30 years is quite hypothetical, real data will start appearing in 25 years.

The whole concept of battery loss tends to be the combination of some lesser performing batteries, battery sizing, and range anxiety.

For the 2015 Leaf, with 88 miles, 20% batter loss over 6 years dramatically cuts into the range of the car. So there is a larger desire to treat the battery well, because the current owner may pay the price, especially when selling the vehicle.

But for the LR Model 3, a 20% battery loss over 6 years isn't as bad of a thing. You are down to about 250 miles range, which is still pretty useful.

Now, some of the original Tesla batteries are starting to show some pretty good 10 year numbers, and as such, that tends to alleviate a lot of peoples anxieties. But, Tesla has changed their batteries, so we need to always check the current battery chemistries.

So, as long as you try to minimize time in any of the three categories above, you should be in great shape. I will say that the first and the last point aren't that big of deal, the second point, going to 0% is something that you really don't want to do. Going to 0% generally huts most batteries pretty badly.

I remember in older vehicles, that with standard lead acid batteries, they can least well over 4 years. But if you drain them to 0%, well, do it 3 times and you have to but a new battery.

 

[xyeahtony]

Technically speaking batteries dont like being discharged all the way and charged full (so under 20% and above 80%). Thats why the battery in your smartphone becomes crap after a couple years.

That being said, Tesla has such an advance battery management computer so you don't have to worry about the battery prematurely dying. If you baby it, sure your battery might last 15 years, and if you dont then it may last 10 years. oh well big deal.

That being said, the closer you stay in that 50% range, the healthier it is for the battery. I charge to 80% because I rarely ever need the full range of my car. I drive less than 100miles/day.

 

[gambit48]

It's a $60,000 car, with the most expensive part being the battery.

80% still gives me more than enough range for a ton of daily driving. So, why in the world would I charge to 100% if there's even a slight risk of damaging the battery in any capacity?

If I'm going on a long road trip, sure I'll charge to 100% if I'm immediately using it.

But for daily use, there's simply no reason why anyone should charge to 100%. Even if the risk was merely 1% that any damage would occur, why would you?

 

[Shock-On-T]

I am seeing many people not charging to 100% and draining down to zero. Most are recommending charging at 20% and maxing it out at 80% to prevent battery degradation.

So people are using 60% of the battery from day 1...but every metric I've looked at takes a Tesla battery to degrade down to 60% after 20-30 years.

So why artificially degrade your battery down to 60% on day one in fear that in 30 years..it'll may actually degrade down to 60%? So the payback period starts after 30 years. Everyone keeping their Tesla for 30 years here?

So that the full (nearly) 100% remains available to you during those 30 years, should you need it.

 

[gregincal]

So that the full (nearly) 100% remains available to you during those 30 years, should you need it.

Exactly. Generally most people don't need full range every day, or even 95% of the time. Why wear the batter more than necessary when you don't need it? However, that doesn't mean you don't charge to 100% and drive to 0% (or as close as you are comfortable) whenever you need to drive a long distance.

Most people always know in advance when they are going to be driving more than 200 miles.

 

[animorph]

Most of the time I have no need for even 60% of the battery capacity. So it costs me nothing to to stay within 20%-80% most of the time.

During a road trip I start out at 100% (charged just before we leave) and try to have at least 10% when I reach a Supercharger (mainly so I have options if a detour or power outage occurs). I'm happy to charge to 100% anywhere along the way when I will be continuing the trip immediately, but not just before an overnight stay. However, most of the time it's usually 80% or less to reach the next Supercharger and with the 100D I can usually reach a Supercharger with 20% charge remaining without too much charging delay.


We'll see how that works out in a few more years.

 

[Glamisduner]

Will the model 3 actually allow you to drop to 0 though?

I'm pretty sure my volt does not charge to 100% or discharge to 0, even though thats what is says while I am charging the battery. I certainly use the battery up 100% every day since it only lasts for 42 miles.

 

[mtndrew1]

Lithium ion batteries degrade faster at very high voltages and very low voltages, particularly at high temperatures for long periods of time.

If you don’t need the car’s full range on a daily basis it will slow degradation to limit the charge window you use. Regularly using a 50-80% charge will result in less permanent degradation than doing the same driving in a 70-100% window.

There is no warranty on degradation that I’m aware of so you’re just reducing the long term functionality and resale value of the car to charge to 100% every day if you don’t need the range.

 

[EV-lutioin]

Technically speaking batteries dont like being discharged all the way and charged full (so under 20% and above 80%). Thats why the battery in your smartphone becomes crap after a couple years.

That being said, Tesla has such an advance battery management computer so you don't have to worry about the battery prematurely dying. If you baby it, sure your battery might last 15 years, and if you dont then it may last 10 years. oh well big deal.

That being said, the closer you stay in that 50% range, the healthier it is for the battery. I charge to 80% because I rarely ever need the full range of my car. I drive less than 100miles/day.

I've heard a lot of people say 80% is better than 90%, but I wonder if there is any solid data showing that charging to 80% is better than charging to 90%? Or is that just to be on the safe side?

 

[xyeahtony]

I've heard a lot of people say 80% is better than 90%, but I wonder if there is any solid data showing that charging to 80% is better than charging to 90%? Or is that just to be on the safe side?

Batteries have a set number of charge/discharge cycles. The closer you get to 100% and 0%, the closer you get to one full cycle. So 80% isn't as close to 100% as 90%, so technically going to 80% extends the battery slightly longer. Does this matter in real world situations? probably not.

Tesla battery expert recommends daily charging limit to optimize durability

 

[lupend88]

Because 50% is the sweet spot for the battery, and because I use about 20% of the battery each day, I charge to 60% overnight. That way the highest I get is 60% and the lowest I get is 40%, which is right in the middle of that 50% sweet spot. Like others have been saying, of course I charge to 100% if I have a roadtrip the next day.

 

[Rocky_H]

I've heard a lot of people say 80% is better than 90%, but I wonder if there is any solid data showing that charging to 80% is better than charging to 90%? Or is that just to be on the safe side?

There is plenty of battery study data that shows it as far as what is best or ideal. But realize that it's like an exponential scale of effect. For a 5% difference of charging levels, it has a bigger impact the closer it is to the extreme ends of the charge scale. So using 95% instead of 100% constantly has a very big impact. 90% instead of 95%--less impact. 85% instead of 90%--even less impact, etc. So yeah, by the time you're talking about 70 versus 80%, it's not making very much long term difference because both are pretty significantly away from the maximum charge, so you're already getting the most significant gain in extending the battery lifetime.

 

[WileyTheMan]

It certainly a balance of battery management and need. I kept the charging limit at 90% (where it was at delivery), and I rarely ever let it get past 50% because my primary charger is a 120v/15a circuit and it would take an eon to charge it back up to a usable range. It's always plugged in at home. Once I rectify the situation, I will be more comfortable with letting it go farther before recharging.

But the thing is, I don't intend to keep this car much beyond 10 years before switching up. History has shown so far that long term battery degradation in Teslas is really good, so I'm ok with not babying mine.

 

[Graffi]

I am seeing many people not charging to 100% and draining down to zero. Most are recommending charging at 20% and maxing it out at 80% to prevent battery degradation.

So people are using 60% of the battery from day 1...but every metric I've looked at takes a Tesla battery to degrade down to 60% after 20-30 years.

So why artificially degrade your battery down to 60% on day one in fear that in 30 years..it'll may actually degrade down to 60%? So the payback period starts after 30 years. Everyone keeping their Tesla for 30 years here?

Think back to those ancient times, back in the dark ages, when we all drove Gas cars. How often did we go to the gas station? Did you stop by a gas station to fill it up every evening before going home? Did you get up in the morning to a full tank every day? How often did you have full range available on your car? My wife never let ours get below 1/4 tank, due to an article she read years ago about being prepared in an emergency. For me, I would wait until the gauge was on E or the light came on. As long as I had enough Gas to get me where I was going and back home again I was happy.

Same with an EV, except we are able to fill-up every night by plugging in. No need to have more than is needed the next day.

Now, why not just keep it at 100%? The answer is simple. We do everything we can to not stress the battery.

Heat puts stress on the battery.
Leaving the charge at 100% puts stress on the battery, the longer it is there the more stress.
Discharging very low puts stress on the battery, the lower it is the more stress.

The least stressful place to be is 50%. Therefore if you need 40% capacity or less for that day's driving you charge to 70% and use it down to 30%. If you need 60% then charge to 80% and discharge to 20%. For me, at home it is set at 70% unless we need to drive it more distance for any one day. On long trips I start out at 100% then try to not discharge below 20% before using the Supercharger. While there I only charge for what is needed to get to the next SC plus my 20% reserve. I may arrive at the next SC with anywhere from 15% to 25% (and sometimes less than 10%) but my goal is 20%. If I only need 30% to the next stop then I charge to 50%. The only time I go higher is if we will be at the stop longer, such as eating.

On our last trip across the country we charged close to 90% twice, and once it stopped at 90% so I changed it to 100% on the app so we could finish and get back to the car before it actually reached 100% and stopped. It actually showed 99% when we left the SC.

Hope this helps. Do not stress yourself about reducing stress on your battery. Just enjoy your Tesla!!! If you do drive great distances on a daily basis, then please set it at 100% every night when you plug in at home. Just remember it is HEAT that damages the battery so try to find ways to avoid excess heat. jmho

 

[Duckiesauce]

I don't think I've heard the discussion about how "often" it should be charged. For example, if I have a really short commute a particular week that between 20% - 80% will last me the whole week, should I still plug in everyday to get it up to 80% every morning? Or should I not plug in until it gets closer to 20%? Hope that wasn't too confusing

 

[Rocky_H]

I don't think I've heard the discussion about how "often" it should be charged. For example, if I have a really short commute a particular week that between 20% - 80% will last me the whole week, should I still plug in everyday to get it up to 80% every morning? Or should I not plug in until it gets closer to 20%? Hope that wasn't too confusing

The question isn't confusing, but it just doesn't really matter much. If you are staying away from the extreme ends of the state of charge, you're already doing what's healthy for the battery. So it mainly relates to that you don't need to avoid plugging in if that is going to inconvenience you on having the range available. It's fine to just plug in as often as you remember to, and if you miss for a day or two, it's not going to help or hurt anything. So it's the decent advice that fits everyone to just go ahead and plug in to keep the habit and to not get caught without range if you need it.

 

[Duckiesauce]

The question isn't confusing, but it just doesn't really matter much. If you are staying away from the extreme ends of the state of charge, you're already doing what's healthy for the battery. So it mainly relates to that you don't need to avoid plugging in if that is going to inconvenience you on having the range available. It's fine to just plug in as often as you remember to, and if you miss for a day or two, it's not going to help or hurt anything. So it's the decent advice that fits everyone to just go ahead and plug in to keep the habit and to not get caught without range if you need it.

I guess you formulated my question better and answered it. Basically I wanted to ask if it hurts anything to plug it in even if I don't need the range and the answer sounds like it's a "no" (as long as I set it to 80% or less as the max). Thanks!

 

[Cycle11111]

This link is very useful. It seems to show the really bad thing is discharging to zero with some correlation that excessive supercharging to 100% is bad. Not sure it shows any difference between 80/90% nominal charging. Also seems to show semi-regular super-charging is fine just do it a lot to 100%.

MaxRange Tesla Battery Survey