Best Battery Usage Strategy for a low mileage user.

[73Bruin]

i have had my MY since 12/10/21 and am still trying to get the lay of the land regarding when to charge and how much to charge. As background, my wife and I put on about 11,000 total miles annually between our 2 cars (we are retired). I expect the MY to get about 8,000 of that assuming we make a couple of road trips. As you might imagine, we can go days without using the car. My current strategy for non-trip charging is to try to recharge at 40% of the range (about 130 miles left) and only charge to 60% of the range (about 195 mile). I am basing this on articles for getting the best battery life on laptops.

I have no clue if this makes sense for the MY. However, it was somewhat confirmed (by my reading) of a 2006 blog article on the Tesla site that referenced calendar life versus the charge cycle life. I guess the alternative would be to plug in every night and maintain a 75% charge for regular usage. I would appreciate any suggestions.

 

[animorph]

40% to 60% is fine. No reason you can't leave it plugged in and set the charge limit to 60%. The idea is to keep the battery around 50% most of the time. I leave my X at 70% when we're not on a road trip. We use 80% for our 3, where we want a little more range available.

We used to drive about 4,000 miles on our most used car. That jumped to 7,500 when we got the 3. It's just too much fun to drive.

 

[pt19713]

I recommend reading this, which is more applicable to EVs: BU-1003a: Battery Aging in an Electric Vehicle (EV) – Battery University

Tesla's BMS is quite good, if not one of the best in the business. Your approach is good, albeit on the conservative side. You should be okay with keeping a higher state of charge, especially in colder weather, since there's not much strain on the battery. I would only recommend a lower state of charge if you're not expecting to use the vehicle for extended periods (4+ weeks). Personally, I charge to 70-75%, keep it plugged in, and the car can be idle for 4-5 days. I'd love to go on a trip but the COVID situation is hampering everyone's lifestyle, unfortunately.

 

[MorrisonHiker]

For the Teslas that we drive daily, we set them to 80%. For the Teslas that are driven less frequently, we set them to 50%.

If we know we're going to more driving on a particular day, we will bump the car up to 90% or 100%, depending on how much additional range is needed.

This practice has worked well with us. Our 2017 S100D has less than 3% battery degradation over the past 4 years and can still charge up to 325 miles.

 

[HotIce]

I have my car set to 80% and it sits on the Tesla home charger all day.

 

[Rocky_H]

@73Bruin I think you have thought all of that through properly. You are correct with the studies on batteries that being close to midpoint is the healthy thing for their long life, and you only need to go higher than that to whatever level gives you enough driving range to enjoy practically using the car. So if 60% gives you enough range that you don't feel stressed or inconvenienced, then that's good. But it's kind of marginal benefits, the farther you are away from the top end. So the differences between 60 or 70 or 80 are probably not going to be very noticeable long term.

 

[mark95476]

That's amazing!

For the Teslas that we drive daily, we set them to 80%. For the Teslas that are driven less frequently, we set them to 50%.

If we know we're going to more driving on a particular day, we will bump the car up to 90% or 100%, depending on how much additional range is needed.

This practice has worked well with us. Our 2017 S100D has less than 3% battery degradation over the past 4 years and can still charge up to 325 miles.

 

[73Bruin]

I would like to thank everyone for their comments. As a further note, other than road trips, we typically drive 10 miles or less and again not every day. The most frequent exception is my wife taking her 80+ mother for doctor visits and these are seldom more than 60 miles per day and that is itself an infrequent event that I can plan for. My goal is to hopefully get 10 years out of the MY.

 

[outdoors]

@MorrisonHiker on your 2017 what is you miles to date if you don't mind sharing. We have same build month. I am at 5.8% @138k. We charge to 90% all the time because of usage.

I would second the 50-60% for such low usage. That is what our 3 sits at currently as it sits jealousy next to the S getting used daily

 

[MorrisonHiker]

@MorrisonHiker on your 2017 what is you miles to date if you don't mind sharing. We have same build month. I am at 5.8% @138k. We charge to 90% all the time because of usage.

I would second the 50-60% for such low usage. That is what our 3 sits at currently as it sits jealousy next to the S getting used daily

The 2017 S100D has right around 48k miles. It was charged to 90% for the first two years, 80% the third year and 50% for the past year.

5.8% at 138k miles still sounds pretty good.

 

[73Bruin]

A follow-up question. In reading the articles, it seems like charging rate can impact battery life (albeit if I read correctly the Tesla BMS controls this). Do you think that there is any harm in taking the MY to a supercharger station if I keep the max charge at 60 or 75%? The closest supercharger 3.4 miles away has 250kwh chargers. I have a 1000 free miles that expire in June and it seems like this is the cheapest way to charge for the time being.

 

[pt19713]

The BMS does a great job in handling the heat and will throttle back the rates as needed, so the supercharger is ok to use.

 

[acarney]

Sitting above 90% and below maybe 5% to 10% and supercharging is what will stress the battery. That said, Tesla made these cars to be used and supercharged. If you supercharge it a handful of times a year during some road trips and stuff you're going to be fine. The cars weren't really designed for supercharging being the primary or only charging method, weekly or even daily supercharging is what will really stress that battery. If you want to go on a road trip though, don't worry or stress about supercharging and don't make long stops at midpoints to try and avoid using a supercharger or something, enjoy the car.

I kept my SR+ Model 3 at 75% charge during the year I had it (before I traded in for a Y) and only put 7,000 miles on during that year time frame. I'm about 5 miles away from my work so most the time the car saw about 10 miles a day and then maybe twice or three times that during the weekend. At home I used the mobile charger that comes with the car on a 50 amp 14-50 plug. I took a handful of road trips in summer and winter weather and supercharged maybe 15 to 20 times total (some sessions were opportunity charges [bathroom break] only and just added 10% to 20% in the session) and charged the battery to 100% maybe 10 times total (it was an SR+, needed all the range for trips). After that one year and around 7k miles I was under 1% battery degradation. Overtime I did see up to like 2 or 3% degradation, but then a decent charge/discharge (say driving for 75 miles or something and coming home and charging back up to 75% in one go) would seem to recalibrate things and my degradation would then decline a bit.

The Tesla battery technology is the best out there right now. Don't abuse it with daily supercharging or constant 100% charges and the car will last a long time. Your charge limits are fine, but I think you probably could bump up to 70% to 75% and not have any issues, even if the car sits for three or four days at a time.

 

[jcanoe]

A follow-up question. In reading the articles, it seems like charging rate can impact battery life (albeit if I read correctly the Tesla BMS controls this). Do you think that there is any harm in taking the MY to a supercharger station if I keep the max charge at 60 or 75%? The closest supercharger 3.4 miles away has 250kwh chargers. I have a 1000 free miles that expire in June and it seems like this is the cheapest way to charge for the time being.

Frequent use of a SC will affect the battery, over time Tesla may limit the maximum charging rate to protect the battery pack. That is not to say you should not use a SC when on a trip that is its intended use. Another option is to search for an Urban SuperCharger. The Urban Supercharger is limited to 72kW charging rate. Keeping the charging rate of a lithium battery below 1C where C is the capacity of the battery pack is one of the things that can maximize the useful life of a battery. By comparison a V3 SC, at peak charging rate is more than 3C.

 

[DonaldBecker]

My understanding is that the best state of charge for storage is around 80%, not around 50%.

The preferred cycle range is not symmetrical, and not centered at 50%. You get better cycle life if you do the same cycles at a higher state of charge, centered somewhere around 60-75%. You especially want to avoid the discharged end of the range. Charging above 90% puts less wear on the battery than discharging below 20%.

But keep in mind that these are minor effects. Follow the recommendations if it is easy and convenient, and don't be concerned if you can't always do it. The battery management isn't going to allow rapid wear without some effort (e.g. trying to get the last few miles when 0% is displayed).

 

[acarney]

Frequent use of a SC will affect the battery, over time Tesla may limit the maximum charging rate to protect the battery pack. That is not to say you should not use a SC when on a trip that is its intended use. Another option is to search for an Urban SuperCharger. The Urban Supercharger is limited to 72kW charging rate. Keeping the charging rate of a lithium battery below 1C where C is the capacity of the battery pack is one of the things that can maximize the useful life of a battery. By comparison a V3 SC, at peak charging rate is more than 3C.

This, even the "limited" rate of cars that have seen extreme use is like 40 to 60kW, so it's still a decent amount of power. A L2 charger, Chademo adapter, or even 72kW supercharger is considerably more "gentle" than the full on 150 to 250kW supercharger rates.

But again, use and enjoy the car for road trips, you fall well into a "normal usage" situation. It's the people using the cars for fleet, ride share, business work, etc that are starting to see those issues (and the personal use people that do like 50k a year )

 

[Zoomit]

My understanding is that the best state of charge for storage is around 80%, not around 50%.

The preferred cycle range is not symmetrical, and not centered at 50%. You get better cycle life if you do the same cycles at a higher state of charge, centered somewhere around 60-75%. You especially want to avoid the discharged end of the range. Charging above 90% puts less wear on the battery than discharging below 20%.

But keep in mind that these are minor effects. Follow the recommendations if it is easy and convenient, and don't be concerned if you can't always do it. The battery management isn't going to allow rapid wear without some effort (e.g. trying to get the last few miles when 0% is displayed).

Here are two references that seem opposite to the above comment:

• Tesla provides the following statement in their EPA applications: “To maintain service life, the battery pack should be stored at a state of charge (SOC) of 15% to 50%.”

• This graph shows a significant improvement in Li-ion battery capacity retention when stored at 15% instead of 90%.

Source: https://res.mdpi.com/d_attachment/applsci/applsci-08-01825/article_deploy/applsci-08-01825-v2.pdf

 

[acarney]

I would like to see what the definition of “stored” is, it might be something like no use (charge or discharge) for like 30+ days or something...

 

[Watts_Up]

I would like to see what the definition of “stored” is, it might be something like no use (charge or discharge) for like 30+ days or something...

I wonder if there is any freight recommendation when shipping a large amount of batteries oversea
using containers full of batteries in a boat or by air?

Should the batteries been depleted to lower fire risk?

What the SoC used by Tesla when shipping 7,000 cars in a boat?

Is there a special 'Shipping' mode for the Tesla cars during the two months of shipping so the cars reach a very deep sleeping state?
- I noticed that my 12 V battery get recharged by the DC/DC internal charger for about two hours every two days.
- Also the pumps are running even when the car is sleeping.​

 

[frankvb]

I wonder if there is any freight recommendation when shipping a large amount of batteries oversea
using containers full of batteries in a boat or by air?

I work for a company that does that (but consumer electronics, battery size much smaller of course, few Ah). IATA has set a limit to 70% on shipping batteries inside a device, and I think a different (lower) one for just shipping batteries by themselves. Note that these regulations may have been updated since then.

I'm not aware of regulations for surface shipping, might depend on the carrier.