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Best Charging Practice for Battery
- Thread starter Robert_Phoenix
- Start date
Correct. 100% is best saved for trips.
When you get the car. (assuming you don't have it yet?) You can set the charge limit on the main screen, or in the app. For instance, ours is usually set to 80% since we drive 40miles a day max. Then the night before a trip we set it to 100%
When you get the car. (assuming you don't have it yet?) You can set the charge limit on the main screen, or in the app. For instance, ours is usually set to 80% since we drive 40miles a day max. Then the night before a trip we set it to 100%
Swampgator
Active Member
I would recommend reading the manual. Or as some on this forum like to say, RTFM
But to answer your question, Jeff Dahn, leading battery researcher and Tesla collaborator, has said 70-75% is the best for current Lithium Ion Batteries. Just charge to 100% when getting ready for long road trips.
Yup. You just need to move the slider on your battery icon in the car. The rule of thumb I've seen is to stay between 20 and 80% as much as possible.
Thanks everyone for the responses. I haven't taken delivery of my RWD car yet, but should this week!
TT97
Active Member
Here is the link for the Owner's Manual:
https://www.tesla.com/content/dam/t...Owners Manual.pdf?vin=NVlKM0UxRUFYSkYwMjA3MDM
It helped pass the time while I was waiting for my 3.
Manual covers this pretty well. The link another poster provided is a really good idea...I read the manual while I was waiting, too. Charging at really low and really high levels throws off heat. Yes, you can set any charge level you want and what time to start charging.
5_+JqckQttqck
Active Member
Depending on your commute, you want to float at 40% to 70% for optimal pack longevity. However, Tesla's BMS is way ahead of the data that this SOC range is based off of. University of Waterloo professor that did endurance tests for Tesla says 70% is a good SOC to be around for daily driving. Top it to 90-95% for trips; 100% if you can hop in and drive off right away without sitting at 100% for extended time.
No higher than 80% for daily use. Charge to 100% every few months or so and let the car sit for 12-24 hours. Sitting at 100% SOC is not good for the battery life, but it is offset with letting the BMS do some optimal top end balancing. The balancing will limit cell to cell voltage variation, which if left unchecked, can begin to limit range and power over time. This advice comes from my experience as a battery test engineer for a few other OEMs, and a little help from a few company insiders. Granted, my advice could also be incorrect if Tesla has, or will, unknowingly change(d) their BMS algorithms. Also, while less of a concern for Tesla's with their big batteries and good thermal management systems, its good to keep in mind that heat can play a big factor in cell life. The more time a cell can spend at 80 degrees or less, the better. But, these sorts of things are all highly dependent on electrolyte additives and other black magic that battery cell producers seem to be able to brew up.
With that said, the best people to comment on this would be Tesla's BMS people and Panasonic's cell life experts. So, if any of them give their advice, take there's over mine, every time.
With that said, the best people to comment on this would be Tesla's BMS people and Panasonic's cell life experts. So, if any of them give their advice, take there's over mine, every time.
This spreadsheet is very helpful. Basic message is charging less than 100% most of the time is a good idea but little difference between 70%, 80% or 90%. Definitely bad to run the battery down to 0%.
MaxRange Tesla Battery Survey
MaxRange Tesla Battery Survey
Model3Guru charge calculator
Just found this - seems for the most part inline with the feedback in this thread.
Agree with the 80% rule but the idea to charge to 100% and allow 12-24 hours before use is interesting. Where did you find this info - can you share the source?
I'll be commuting ~30mi round trip for work. For an LR battery @ this range the calculator suggests an optimal min charge of 65% and max charge of 75%, taking 49m on a NEMA 15-40. We will of course drive much farther on the weekend and on those days charge between 80-100% as needed before we go, but in general I think an 80% max cap outside the weekend is a good sweet spot.
Maybe it's not really necessary to charge exactly at 65% and only to 75% but it sounds about right as a best practice. Anyway - the above calculator seems helpful and at the very worst will do more good than harm.
Thoughts?
Just found this - seems for the most part inline with the feedback in this thread.
Agree with the 80% rule but the idea to charge to 100% and allow 12-24 hours before use is interesting. Where did you find this info - can you share the source?
I'll be commuting ~30mi round trip for work. For an LR battery @ this range the calculator suggests an optimal min charge of 65% and max charge of 75%, taking 49m on a NEMA 15-40. We will of course drive much farther on the weekend and on those days charge between 80-100% as needed before we go, but in general I think an 80% max cap outside the weekend is a good sweet spot.
Maybe it's not really necessary to charge exactly at 65% and only to 75% but it sounds about right as a best practice. Anyway - the above calculator seems helpful and at the very worst will do more good than harm.
Thoughts?
Well, here's the thought: it's not a linear effect. So every amount of difference is not the same. It depends on where that amount of difference is. The most impact is the closer it is toward the extreme full and empty ends. So let's say that you are looking at a 10% difference in state of charge. You do the most good using 90% instead of 100% for your constant daily limit. But the difference between 80 and 90% is less, and the difference between 70 and 80% is even less than that. So by the time you're debating around the 70-80 level, it's like the kind of thing that you might possibly be able to detect a difference in 20 years of use; you've already got the major benefit. So it's up to you to balance how far down you want to go for barely perceptible degradation benefits versus having plenty of driving range for your use without feeling worried about it often.
Let’s just say I may know someone in the right place to see the right vehicle data from the right vehicles to know.
But, I also have experience as a battery test engineer for major OEMs. The strategy I mention also jives with my experience interfacing with BMSs. The BMS needs an opportunity to balance the cells to even out the voltages and keep them consistent and tightly grouped to each other. This allows for maximum usage of the energy out of the cells as a group and allows you to charge them at a higher rate as well. If you have cells that are out of balance, when a load is applied to battery pack, those out balance cells will likely move to a different voltages than the other cells that are in balance. As time goes on, that variance will increase and eventually, you start hitting lower voltage cutoffs early, reducing your range.
It is my understanding that the BMS on Teslas doesn’t read each individual cell, but several in parallel. So, those cells are constantly working to balance to each other naturally, but the BMS does not have individual control over any specific cell. This is one of the reasons why letting the pack sit for a bit after a full charge on a Tesla should help, because it gives the cells time to settle out and the BMS time to actively work the balancing circuits to keep everything even. The balancing circuits are likely active during charging, and will end up doing a lot of work towards the end of charge, but I'm assuming (based on some help from the right people) that the circuits are active even after charging has stopped. So, while letting a cell sit at high SOC for long periods of time degrades the cell more quickly, keeping the pack balanced is also very important from a practical perspective. If the battery spends 95% of its time at 80% SOC or less, and is allowed to balance at full SOC for the other 1 to 5%, its probably a lot better than never allowing the pack to spend some time balancing cell strings at 100% SOC.
Just to be clear, this strategy is predicated on the assumption that the balancing circuits are active even after charging has finished.
You’ve received a lot of good advice in this thread. But as a Tesla owner for the past 4+ years, here’s mine: don’t overthink it. Plug the car in every night and set the charge level to whatever you need for daily use plus 20%, don’t exceed 80% unless you know you will need it for a trip. The car will take care of itself.
Super helpful, thanks for the detail. If balancing is still occurring after unplugging then it makes total sense. I guess the question I still have is, as a best practice, what's the sweet spot (in hours) for allowing it to sit @ 100%, or better yet, the threshold at which it does more good than harm... but that's probably a bit ambiguous/subjective.
Well, in any case, it sounds like 80-85% as a cap during the week and 100% on the weekend should work well assuming we are driving on the weekend, which we will be, all the time
So it will likely sit for ~10-12 hours max anyway if not less. I'm sure it will get to stretch it's legs (wheels) every day on the weekend. Even if it doesn't, it will get drained on Monday morning regularly.I know Tesla recommends leaving the car plugged-in while not in use however, I park at the airport every week and am wondering how this may affect my battery. I'm sure it's against etiquette to leave it plugged-in to one of the chargers there, so I'm just planning on leaving it unplugged. I'm gone usually four or five days each week and I only live 25 miles from the airport, so I'm not concerned about range, just about potential battery degradation by leaving it unplugged for up to five days at a time.
Any thoughts are appreciated.
Any thoughts are appreciated.
That recommendation is more so that people will have enough range. There seemed to be a lot of these cultural myths in society among people who don't understand electric cars that leaving an electric car plugged in too long would overcharge it and blow up the battery or something. Tesla is just trying to overcome that fear by letting people know that there is no reason to avoid plugging in, and it's helpful for you to just plug it in as often as you want, so you don't find yourself without enough range to drive. That would spawn complaints of electric cars being deficient, etc., which is negative PR they don't want. Anyway, you mention 4 or 5 days. It'll be fine and not a big deal. You will probably lose somewhere around 1-2% per day, but if you had some decent amount of charge when you get there, it won't be any issue sitting for that long. I mean, think about it: the cars sit unplugged for longer than that just being transported across the country.
Why are you sure of this? Whether it is against etiquette or not is very simply answered by whether this is in a long term or short term parking area of the airport. If it's in a short term area, then sure, those are meant to be used for an hour or two and then leave, but people don't use long term parking for two hours. The whole point of the existence of long term parking is to leave your car sitting there for multiple days, so if there are any charging stations in there, the expected use it to leave your car plugged into them for several days while you are gone. Here is a thread with a whole argument on this about the Denver airport parking areas and charging stations.
Denver International Electric Parking - Teslas Stop Parking There!
Thanks for the info, I won’t worry about.
And thanks for the link to the DIA thread. Seems as though people have varying opinions. I suppose I’m with you, if it’s long term parking no problem leaving it plugged in. But I don’t need to charge since I’m only 25 miles from DIA so I will leave it for those that need it.
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