Should I be charging my EV to 90% each day if I only drive a short distance?
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- Опубликовано: 25 май 2024
- If you drive your EV for less than 40km (25 miles) each day then topping up the battery to 80-90% may be shortening its life. By thoughtful charging you could still have 90% capacity in your battery after 23 years!
00:00 Introduction
01:40 Battery University
02:07 Depth of Discharge
04:27 Maximum State of Charge
07:17 Storage Conditions
08:58 Dynamic Stress Testing Results
13:44 Conclusions
#electricvehicle #tesla
batteryuniversity.com/ 
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PLEASE NOTE:
This information is intended for EV owners who only drive a short distance each day and then plug in each night. The data presented only applies to ternary type lithium batteries (e.g. NMC), not Lithium Iron Phosphate (LFPO). If that isn't your situation then don't waste your time watching or posting irrelevant comments.
Also note that a "DST Cycle" referred to in the Battery University study means one discharge and recharge to the levels specified in the test (e.g 75% - 65% SOC). However the industry term "cycle", when used to predict battery life, means one transition from fully charged to fully discharged and back to fully charged. So there would be 10 X 75% - 65% events before one charge "cycle" is clocked against the battery's lifetime cycle count.
While the science may seem complex the key message is simple:
- You don't need to change your lifestyle or stress about your battery
- You can keep driving as you do currently and plugging in each night so your car is always ready at the start of the day
- If you simply lower the maximum State of Charge (SOC) from 90% to something more appropriate, like 60% this can enhance the longevity of your battery. This is because the battery spends less time standing with a high SOC.
Lastly, I am not telling anyone what they should do, just presenting the science. In the end it's your car and your choice how you charge your EV. Have a great day ! 🙂
All irrelevant if you have a car on a 2 year lease
Just charge it and enjoy it 🎉
@@rambleon1182 yeah don’t worry about the car only lasting a few years because the battery is naffed. We’ll just get a new one anyway, and tech is changing that quickly that you’ll want the new tech anyway.
@@jlrguy2702
Exactly they are not cars just mobile tech platforms with a very short real life buy a new ev now and in 2 months it will have lost 50%of its cost price just get a good old V8 muscle car and enjoy your drive
You should revoke the video or at least the commentary, because the advice you give is leading to increased battery degradation. As others point out, the light blue line would result in the maximum extracted charge before reaching 90% soh.
I own my model P85 for 10 years already. Not a sign of battery degradation because I never charge above 80 %. When I don't use my car for a while it stays on 50%. Then when I am going for a trip I charge the power I need for this particulary trip.
Sometimes I supercharge up to 80% to heat the battery to
get a temperature to remove condensation and water out of the battery pack. Corrosion in the electronics also damages it.
Still super satisfied with my Tesla after 100.000 miles.
Did ever any cell failed as it happens to ebikes all the time? One cell goes out and you have to buy a new battery, for it's too expensive to fix it. I wonder what happens in a car. Do they separate like packages of 6 or 12, and the system just jumping over them? Maybe they can be replaced? Can you enlighten me, please?
I think the math is a little off here. Since let's say your commute is the 10% you're talking about. If you would do the 100-25% charge, you can drive for 7,5 days before charging (so 7,5*1000/365=20 years), while with the orange line you need to charge daily. So if you look at it that way the light blue and pink are the best modes 5*3000/365=40 years or 3*5000 which is the same. 40 years seems very unrealistic to me, since you will have so degradation over time itself (storage). So all in all I don't think the factory 80-25 is all that bad. Maybe 75-25 or 75-40 might be bit better. I now charged up to 80% so I think I'll set it to 75 instead. My commute takes a bit more of the batter though, about 15%.
I agree, you need to convert the number of cycle and DoD into KWh and then you can see which strategy have most battery life (in term of power discharge until battery degrade to 90%)
From the last chart I think the 25-75 charging strategy @ 3000 cycle will output most energy before reaching 90% battery degradation.. putting that number for my ionic 5, that translate to around 108,000kwh power discharge and @ 5km / kWh (low estimate), the battery will last 540k km. At 25k km per year that is 21 years of driving... So that means after 20 years I will still have 90% battery capacity. But I live in tropical country and the normal temperature here is around 33°c and sometime I charge to 100%. so maybe 10 years is more accurate estimation.
The terminology is confusing. In battery technology, a cycle is considered full capacity of the battery. So a 10% charge is 1/10th of a cycle.
@@lampe36there is no true understanding of cycles except for general term of cycle meaning the returning of a state.
So short cycle is a cycle that is not equal to a long cycle which is also a cycle. A cycle is a cycle but not all cycles are the same. Measuring longevity in cycles is a terrible unit to use in most cases when cycles are not the same cycle. It’s like comparing the price of things in pennies but some things are in Australian pennies, some in Euro pennies, some in American pennies, and etc.
So I agree on both the math being odd, and radically unequal “cycles”… however, given I usually drive < 20 miles, it will have zero impact on my life if normal daily charging is to 75%.
@@BrianThorstadyes it’s pretty much the same thing I said about my civic when I was offered a regular oil change versus a synthetic oil change. Is it really going to make a difference?
In our training from GM for the Bolt EUV we have been told to recommend to customers that they use the moto ABC: Always-Be-Charging. Their explanation was that the car will manage the battery temperature while the car is parked. One fellow on RUclips has a short video showing his Bolt expelling excess heat during a very hot day. His car wasn't running, just plugged in. So while not charging everyday may be a good idea that would be only when the outside temperature is neither too hot or too cold. At least where GMs are concerned.
Charging to a lower level most of the time seems to be a good idea that most agree on. My cell phone has a battery management setting that you can switch on and it limits the charge to 85%. This is meant to increase battery life (Samsung phone).
I drive a Bolt EUV and have set my maximum charge at 80%. I may lower that to 75%. I also use slow charging as it seems to be recommended by most.
Thanks for the video. I found it most useful. In addition, the comments left by some viewers also contributed to my battery education.
Thanks for adding to the conversation Phil. You make some good points here. I think your suggestion is probably the best approach. Plug the car in each day but set the maximum SOC to the minimum you will require to complete your daily commute. In my case I only travel 14kms (7 miles) each day so I can get by with charging to just 60% and only increase this if I'm planning a long trip out of town.
The reason GM likely instructs people to always charge their car, is because it reduces range anxiety, performance is at its peak, you'll likely never get stranded with a dead car, all of which reflect poorly on the car/EVs. Manufacturers dont care if 7 year old cars have decreased battery health, they already profited, and arguably degrading battery health means consumers buy more cars. What is best for manufacturers isnt always best for consumers.
I have a Bolt EUV and follow the ABC mantra. However, I set my max charge level to 80% on the Charging settings so its never fully charged. Only when we go on roadtrips do I take that setting off.
the reason why is because the bolt is more willing to use the battery heater or cooling system when plugged in but when not plugged in, it doesn't want to drain battery so let the battery heat up.
The really up to date vehicles have heat pumps to manage the battery temperature.
Also important to remember that most manufacturers don’t allow you to use the entire battery. So 100% is not really 100% and 75% is not really 75%
That doesn't really matter for the SOH of batteries however, looking at charging cycles
@@authorified89 why not? my battery is gross 35,5kwh, im only allowed to charge it to 30 kwh, if I charge it to 90%, that will be 27 kwh, and it would be 76% charged. My soh Im assuming is worked out from how many kwh i can get from the votlage that gave me 30 kwh when car was new.
@@bjorn2fly oh I misunderstood then, 75% of 35 kWh is significantly different from 30kWh indeed. Its good to keep in mind the actual battery percentage instead of what the car shows, my bad
I guess tesla is not one of them. %100 is almost true value I think. So we have to pay attention to charging.
Tesla have about 4kWh bottom lock on larger packs. I.e. when a 100kWh battery shows 0% it's true percentage is 4%. You can't use this 4kWh. There is also top lock but I don't know the figure. @cigersuz
The magenta (75%-45%) most closely represents my usage cycle and I charge twice a week which = 43 years (I'll be 106 years old)
btw - the warranty is 80% and I had a starting capacity of 331 miles so at 90% I still have 300 miles of range & (80% = 270 miles) which is still quite usable
do you realkize that even without any cell degradation you will see the range when fully charged change as much as 30% in the winter when using the ambient heating? stick with seat heaters.
Can certainly be more than 30% degradation in winter.@@didyuknow
@@didyuknow more like stick with an ice vehical. ev owners have to be insane. dont use the heater, use blankets and the seat warms. what kind of ghetto cars are these.
@@didyuknowpeople think it's the cabin heater that draws all that energy, but most of it is battery heating. Keep the heater on 😂
A lithium-ion battery is happy between 25% and 80% SOC. However the BMS needs to know the extremes as well so do go to them occasionally. It is okay to charge to 100% but it is bad not to use this first 10-20% shortly after: like if a battery being under stress while fully charged: the shorter we leave it in that condition, the better. So please just charge to 100% the night before occasional long distance trips.
And happier between 20-50%. At the end it’s about adjusting to your daily usage
That's why I am glad to see the data, otherwise we only have stuff like "battery is happy" to base decisions on. Batteries are incapable of being happy.
My usage varies from 20 to 110 miles each day. I charge my 2021 Ford Mach E at home to 90% daily as recommended in the owners manual. With over 60,000 miles on the odometer I don’t see much degradation. Charging to 90% still shows 238 miles of range
@@irfanhusein1445 That's fine but there is little reason for you to not drop it to 80%.
@@AlexLplusbattery is happiest at 50%, so 35-65% would be much better than 20-50%. That's too low to go if you are trying to extend battery life to the max.
You omitted the fact that part of this 'precautions' are already done by the BMS auromatically. If you charge to 100%, this is not really 100%, as the battery physically has 8% or so more capacity, which is 'fenced off' by programming in the BMS. Similar at the low end...
I put over 250,000 miles on 4 plug-in hybrids over the last 10 years. They had a built-in battery buffer of 20%, so that "100%" charged/full was actually only charging up 80% of the battery. The result was that none of the PHEVs showed ANY visible loss of range during the time that I had them. Granted, because 20% of the battery capacity was not shown to the driver, they could have lost up to 20% of their capacity without it being seen. But they also could have actually lost minimal battery capacity over the years of daily driving and charging (L2) use.
What plug in hybrids do you have? And how is the battery after 10 years?
It lasted that long because the majority of those 250,000miles where driven with an ICE engine.
If someone uses the electric part of their hybrid a lot, the battery cannot last that long, because the battery will go through charge cycles like crazy.
If a hybrid does 30miles on it's battery for daily driving and someone would actually do those 30miles every day on the battery, they would have accumulated more than 1000 full cycles in less than 3 years.
@@Tschacki_Quacki hyundai have done tests where battery management can give battery up to 8,000cycles!
@@niallchurch2679 Yes, if you use the battery only between 40% and 60% you probably get 8000 cycles.
A laboratory is not real world usage.
Excellent points, Mark.....thanks for doing the hard work to investigate the subject. I would add though that it is important to prriodically charge to 100% SOC, in order for the battery management system in most cars to perform cell balancing. Perhaps adopting a routine that the first day of each month, you charge to 100% using level 1 or 2 charge point, and return to your regular routine for the rest of the month, would preserve battery maintenance and maximize service life. Thanks again for doing this.
RUclipsr bjorn said that after charging to %100, you need to discharge all the way to 0-5% at one go to calibrate bms system. Not just charging to %100 and then discharging in a week or so.
(Not LFP then?)
@@lindam.1502lfp should be charged to 100% daily anyway.
I'd save that 100% charge for when you are doing a long trip, timed to end just before you set off, and run it down to 10% to help balancing. No need for once a month, they take 6 months to get out of balance in my experience (Tesla S since 2016). My old S still held 95% original capacity after 87,000 miles.
I was charging to 80% and then only charging when less than 50%. Since, on my daily commute, I always came in right at about 50%, I am going to only charge up to 70% and see how it goes. I am also intrigued by potentially charging at a lower rate too. I can recharge in two hours, but I have 8 hours to do it in over night so am giving that a try too. Thanks for the food for thought.
I have an LFP standard range Tesla, I saw a study where a lab did 90-100% cycles and got about 10,000 cycles out of LFP (probably at 20 C). And that happens to be about my daily usage so most days I do a 10% depth of discharge with maybe a few times a month I go down to 70-80%. Interesting that colder is better. Good thing it doesn't get too hot here in NZ
Good advice for NMC batteries. But, if you have LFP you may not need to worry as much, just top it up regularly. The rest of the car will probably fall apart first.
LFPs have a flatter voltage curve and my understanding is that 100% allows the battery monitoring system to re-calibrate as it is hard to track the percentage on a flatter voltage curve.
Thanks for sharing this. My daily commute is 30kms through motorway which means I don't really need to worry about battery range. I can also recharge less often, keeping within ideal state of charge.
A significant variable to degradation is also depth of discharge (DOD). Avoiding large depth of discharge prevents expansion and contraction of the electrodes which leads to cracking. A DOD 10% to 20% has a little impact on battery degradation above 20% has increasing impact. 20% of discharge provides very little degradation above 10%, but provides twice the mileage driven. Therefore the ideal charging range is in fact 40 to 60%, pushing this to 30 to 70% may be ideal for most peoples practical usage with the additional small degradation being worth the increased usability.
the occasional use of the battery full capacity when needed should not be discouraged unless you want to have a ferrari and drive it at 40 miles/h each day. The trick is to time when to charge to 90 to 100% (i.e. just prior to start of the long trip) and then not letting the DOD to go below 30%. Perhaps a supercharge back to 70% to drive a few more hours will be much better than taking the battery all thne way to 10% or less.
This is good advice. Keeping the EV battery balanced is the best for longevity. I got a 14 year old Prius and can monitor the battery charge level. Toyota seems to keep the battery between 45 and 60% charged. It is still running well on the original battery.
original prius and even new hybrid do not use lithium battery, they use NiMh
Great video. I feel you nailed in your sum up and what you are personally doing with the 40 - 60% cycle, a pity that study didn't include that or even 45 - 55%. I think this rule of thumb would also be great for someone who can only charge by fast charger, if they are also an urban dweller whose commute is short, then they could do this just once or twice a week for probably only ten minutes a time and end up way better off than those who fast charge huge depth all the time.
Also I'd be very interested to see the results if it was dialled back even more to say 20 - 40%, the battery is charging very quickly at this stage because it is under virtually no stress. Could be even better than that mid range.
Just an amateur thinking out loud here :)
Spot on!
We LOVE having plenty of fuel in the tank with an ICE car. We also LOVE having plenty of charge in the battery for an EV, but for the majority of us that’s complete overkill.
HOWEVER keeping the max charge below 65% to 70% is always going to be much better for the battery …. and even more so in hot climates.
If you must fill it, don’t leave it there for long, drive immediately.
If you arrive home near empty, charge it to at least 20% immediately.
@marksjustimagine I understand and agree with the logic of not charging to 100% or discharging to near zero, however, one major flaw in the approach is that charging more regularly (daily) from 35 % to 75% SOC (40% for say 160 km) would require twice as many charging sessions as one charging cycle from 10% to 90% (80% for 320 km)
Number of charging sessions doesn't matter much. It's the total number of charge cycles. One cycle being from 0% to 100%. So topping up by 10% each time, would take 10 sessions to complete one charge cycle of 100%.
Thank you, Mark. An excellent piece of reporting with a clear conclusion which is easy to implement. I will start this immediately.
Thank for the positive comment David!
I've been looking into this question for a week now and finally came across some actual data! Thanks!
Thank you. It kind of fits what I knew about batteries (storage % voltage for batteries waiting to be shipped and sold by battery companies is 65%). Until now I was charging my car at 80% every day (Model Y 2023, Long Range). Now, I will charge my car to 60%, use 3% to get to work, it will stay on parking at work and lose 2% more during the day (sentry mode usage-security), then lose another 3% on its way back, then it will be at 52% and stay that way until the charging start 3 hours later. Friday, I will charge to 80% in case of a longer driving during the weekend.
Even better - charge to 75% twice a week and extra at weekend if you need it.
@@sybaseguru Nope, not in my case. I can't trickle charge more than 17% in a night . And the charging automation of the car work per day so I do not want to manually modify the charging of the car via the app every other day. I have peace of mind the way I am doing it at the moment.
@@mletouutube What? 17% per night? What the hell is charging your car? A solar panel for the moonlight?
@@Tschacki_Quacki Get back to arithmetic class man. 3%+2%+3%=8%
Excellent video, thank you for doing this. I however had a clarification. I was wondering if we should charge from 75-65% SOC, as that seemed to prolong the battery life the most based on the last chart you showed. Although I might have missed an explanation of why you thought the 60-40% was a better charging pattern. Thanks in advance for the clarification.
Were we live and work, lots of people travel over 100 miles per day. So my Leaf, uses 75 to 80% per day. Current at 48000 miles. And the car came with extra warranty on the battery.
Really interesting... thanks for your research and clear summary. My charging routine was to use the 80-20% range but after this, i’m going to follow your recommandation. Apart of course when i’m doing à road trip. Then i slowly charge to 100% during the night befor departure, and using my obd connector, capture the capacity of the battery so that i can follow up battery degradation. ( i have a mustang mach e with edtended battery)
Been basing my model 3 LR off the 75%-25% line, and the battery is doing well, the car is at about 110,000 miles in 4 years. Just plug it in every night, and every morning it's at 75%, much less than is needed for a typical day.
Very valuable information. I have owned a model Y for almost 3 years and have been reviewing charging advice videos. This is the best one I’ve seen by far. Thank you.
Thank you Frank!
@frankpainter7571 Be aware that your Tesla model Y uses a lithium phosphate battery, so has different recharge characteristics than those covered in this video.
Great video. Thank you so much for your work on this. Leaving a comment to show my appreciation, and also to express that for a very technical subject, this video gives a perfect explanation and context of how to optimize your EV's battery life. Cheer my friend. Thanks again!
Thank you victor! 😊
Thanks for this interesting video. My Megane e-Tech EV60 is always charged at 80% and when the percentage is down to 60,50 or 40%, I charge at home with 7 kWh (32A). After one year, Renault told me the battery is of 98% capacity. Now, after hearing what you told, I’ll switch fom 80 to 75%.
Think of it like your own stomach. Don’t wait too long before you eat (get too empty). When you eat don’t eat too much. Basically, be diligent and mindful about it.
Interesting my BYD has a 60KWhr LiFePO blade battery configured 126S1P.
The recommendation is to charge it to 100% once per week. Our daily driving during the week uses about 60%. Consequently we slow charge it (AC3KW) each Sunday (mainly using solar panels) to 100%.
We only fast charge on trips, typically at the 50KW rate. Under fast charging, charging efficiency and rates decrease markedly over 85%, with a good deal of energy lost as heat. So when fast charging we normally stop at 80-90%, particularly if the weather is warm. The BMS rolls the fast charge back anyway over 90%.
On trips we mainly operate between 15% and 90% for an effective range of 300km between top ups. On routes we mostly drive, this works well.
So far we have not detected any battery degradation.
Very helpful - just wanted to say thank you for finding and highlighting this research
You're welcome David. Thanks for the positive comment.
Great video! Exactly the information i was looking for. The doubt about what is the best practice to keep my Tesla battery healthy for longer was turning in my head for a while 👍
Glad it was useful to you 😊
I travel for work and leave my car at the airport for 3 or 4 days in a row every week….so I have to account for phantom drain. I’ve stopped using sentry mode on my Tesla since it consumes about 10% per day 😯. Without sentry mode it only consumes about 1% per day.
Great info! Thanks 4 taking the time 2 make this video. God Bless!
Thank you, you're welcome!
Excellent video! Extremely useful for those of us contemplating the purchase of our first BEV; gives us an idea of how to charge for maximum battery life. Many thanks!
When these tests were performed were they using an actual car and the cars BMS, or were they just testing battery packs or even just cells in a lab setting? Seems the the manufacturers BMS would have a pretty large influence on the batteries and their lifespans, regardless of how much or how little you were charging.
EDIT: Just looked at the article - they were testing batteries for handheld devices, not batteries for automotive use. Not sure these guidlines can be carried over directly.
The basic principles about battery chemistry and how it behaves still apply.
The same tests have been made with all kinds of cell formats and the results show obvious tendencies.
There are two ways to measure cycle life. One, is to count the number of times the car is driven, and the number of times it is plugged in to recharge. The other way, is to measure throughput. That is the total number of amp hours the battery puts out over its lifetime, divided by its rated amp-hour capacity. (sometimes referred to as "equivalent cycles") I do believe this would be the most relevant, because that translates to the total miles the battery lasts in an electric vehicle, before it needs to be replaced. In many cases, the best margins would be between 30% to 70% states of charge. Most manufacturers recommend 30 to 80%, to use the middle 50% of total capacity on a day-to-day basis. Occasional charges to 100% aren't too detrimental, as long as the car is driven immediately after the full charge, and is done only on the occasional long trip where you really need all the capacity the battery has to offer. You don't want to charge to 100%, then leave it at that state of charge for a full day.
I was looking at the cycle life graph of a Trojan golf cart battery, (liquid filled deep cycle lead acid)and calculated the total equivalent cycles, and it didn't make any difference whether the battery was discharged 80% down to a 20% state of charge, or, if it was drawn down 20% to an 80% state of charge. The total ampere hours available over its lifespan was the same! (keep in mind, Lead Acid batteries REQUIRE charging to 100%, to avoid sulfation)
Thanks Vincent for your contribution to this discussion. Indeed it is the second way that most manufacturers use when publishing battery warranty. The key take away from the Battery University study is that, as you suggest, the worst thing you can do is charge to 90+% and then leave the car standing for a day, or even overnight.
Graph at 12:00 : it appears that Yellow is better than purple - but its not. The purple covers a 30% cycle min/max- 3 times more power than the yellow (10% cycle min-max), so I need only charge up a third of the number of times. In fact purple has half the number of cycles at 90% capacity retention, so is providing 50% more mileage. Purple looks optimum on this basis so one should aim for keeping charge in the 45% to 75% range, but dropping to 25% is not a disaster as the blue line shows only a minor degradation hit.
Isn't Black the best then, by this logic?
Very interesting. I only use my model Y once a month and this is the first video I've seen about how to maximize your battery life; other than the usual recommendation of keeping it between 20 and 80%.
The question should be how much will the cost of the battery will be 5-10 years from now to replace. Might only cost a few thousands to replace a battery at the rate of how fast the cost is dropping. Also, by then there will be more fast charger available like gas stations. So do u want to pay a little extra for less inconvenience?
I have been slowly transitioning my home to all electric. It was built with normal natural gas service for appliances. I first installed solar and a Power Wall. Then I installed a heat pump. I am in the process of adding a heat pump water heater and induction stove. I had intended on getting a Tesla Model 3 but the size wasn’t acceptable. By the time the Model Y came out I became aware of Aptera and I like their BEV solution much more than any other focusing on efficiency instead of electrifying a conventional vehicle. I am in California on the central coast so we have mild weather making it much easier. Good luck with your transition.
Great advice. I plan to drop my daily change down a bit more. I dont drive much each day. When I go on trips I do work the battery a bit harder, buts thats only a few times a year. Even on trips I try and keep 85%-25% range more for peace of mind on the low end and charging times on the high end. Super changers tend to slow a lot after 80%, My only concern is the Im guessing the change % on the Tesla display is prob not exactly battery %. That may not matter as I think the main issue is stay kinda in the middle unless you need the range.
Thank you for your hard work and very clear presentation! Thanks also to your source.
Great eye opener.. Thank you for uploading this video.
Thanks, no worries!
Very nice chart to examine and think about. Its funny but I find plugging in to charge at home just enough of a bother to not want to do it so often and wish my Kia got 400 miles of range instead of 275 or less in the Winter. Since I really don't want to get caught too low on one of my slightly longer trips and have to use an expensive and notoriously undependable fast charger I regularly home charge to 90 % to have more usable range. And just to remind myself to charge I usually plug back in at 50%. I wish they had tested a few more variables so I could see more closely what my 90 - 50 % system is doing. Thanks.
I've heard that Li-ion batteries are happiest around 50% state of charge. The data presented here is pretty consistent with that. I think you might be better with 80-40%.
A cycle is 0-100%. Charging 10% daily is only 1/10th of a cycle
That’s not how it works, battery charging and or degradation is not linear!
Cutoffvoltage at tesla is at 3.3v so 0% charge is actually more or less 10-15%
i charge my tesla only to 50% usually thats where it sits 90% of the time if ive got longer distances i charge it a little more just before hand. i havent needed to be outside of 40-60% in the past 6 months
Same as I do with my Kona, typically stay between 45 to 65%.
I know my iPhone batteries have a lifespan more than double the length of everyone else in my home. And usually longer runtime each charge. Everyone else plugs their phone in overnight daily so it’s “fully charged” each day. I never plug in until after I get the 20% warning and whenever I am able, try to unplug between 80-90%.
The info in this video seems to concur.
thanks... was wondering why the 45-55% available stored energy data reading is missing from the table?
I’ve just ordered a Skoda Enyaq. This is very interesting information. I won’t do a great mileage, so I’ll only charge once a week at home. But I’ll probably set the maximum charge to 75% and then charge back up at 40%. Good video and well explained.
Škoda doesn't allow you to use full capacity of battery. So what you see as 80% is probably 75% real capacity already +-
Enjoy your Skoda Enyaq, my Wife has had hers 7 months now with 7000 miles. She loves it.
Thank you for sharing such great information and for the time you took to gather it. If you could help me understand something? I still have a doubt about what is a battery charging cycle? Thank you!
Thanks Baller. A charging cycle is simply what happens when you plug the car in to charge. Regradless of the State of Charge (SOC) when you plug your car in, once you finish charging and disconnect, you have completed 1 charge cycle.
@@MarksElectricLife Then charging partially greatly increases the number of cycles used!
@@MarksElectricLife I thought a complete charging cycle would be to start at s specific State Of Charge (SOC), then discharge the battery by X amount and then charging the battery back to the original SOC.
Very helpful. I think that everybody can get its own lessons. I lowered my limit from 80% to 75% which would mean that my car would sit most of the day in the 55-65% SOC range. I also delayed my scheduled charge in the am so that I drive it only about half an hour from reaching 75%. This seems to fit my driving pattern the best and hope I will be a happy owner for a long time (MY LR).
Ma va là non spararle
So what's more important, is it amount of charges you do or SoC regardless of charge cycles? I'm luck as I only use about 4% a day in my model 3 long range. If SoC is the primary factor then I should do something like 40-60 but if amount of charge cycles is primary then I should do something like 35-75. So which is it for my circumstance?
Thanks for putting this explanation together. It's easy to follow and is well supported by evidence.
I notice nothing here for 80% to 60% that would be a pretty realistic number for most drivers. I have a Ford Focus Electric that I think indicates 100% when the battery reaches 4.06 volts as an automatic safety net. I charge to this level and then run for several days down to about 40%, and even that 40% is not correct because I think they also indicate 0% when the battery is actually at 10% to also serve as an automatic safety net.
Also, if you use the battery 10% per day and het the 8000 cycles, does this meany 80,000 10% cycles equaling the same as 8000 full capacity uses.
I know my car still gets all the rated miles advertised when new and then some at 6 years and 63,000 miles. This could also be due to the fact that I cannot really see full rated capacity anyway and may not notice it until more that 25% degredation. Any thoughts on this from anybody?
There are several mechanisms that degrade a Lithium Ion battery and reducing the maximum charge will reduce one of the mechanisms but these batteries will, in any case, degrade over time and/or if exposed to significantly elevated temperatures. I have not seen studies showing just how much degradation will occur due to ageing alone but the ideal charging regime would be one that maximises available charge capacity without significantly increasing the degradation that will occur anyway due to ageing.
My 2021 Standard Range MG5 is now 56,000 into its life. Probably around 90% of charging is on my home charger at 7kW. I always fully charge it to 100% daily.
SOH as confirmed on its recent service is 99%. It still returns an average of 4.2 miles / kWh and the range is the same as when it was purchased new.
MG have certainly got an excellent BMS and Thermal Control System in the car.
Very interesting. I have a 2019 Nissan Leaf SL Plus that I have had for 4 years as of 1 December 2023. I have attempted to follow the 20-80% battery charging rule, and usually charge my vehicle with Level 2 home charger. As of this date, I have had no problems with the vehicle, and other than tire rotation the vehicle has had no maintenance. My dashboard battery capacity indicator shows maximum bars. Leaf Spy applications indicates that I have approximately 92% of battery capacity as of this date. I am very pleased with this vehicle and would recommend a Nissan Leaf to anyone that needs a vehicle for urban driving.
Your Nissan Leaf SL Plus, is on my first car choices on my next car, may I ask, how many odemetor miles are on the car and is still remaining at 92%?
Note: (one big concen I have about this car in my case, is the batter degradation I might face as I charge the car at night at home (Level 2) when it's still 85 degress
which I would be doing most nights from May until late August, (I I live in Las Vegas )
State of charge % and depth of discharge don't exist in a vacuum, both time and temperature are significant contributing factors.
You need to normalize the data for amount of battery used. For instance the 75-25 cycle gets you 5x the driving distance of 75-65 yet it lasts more than 1/5 of the cycles. So based on this chart a 75-25 cycle seems to be the best option. Just don’t charge it every day.
I’d take a look at you median daily drive and make sure that you battery covers probably 3-4 times that distance at minimum. Then plug it in only when you get to 25% and then charge to 70 or 75%.
There is also time degradation which is why you don’t want an overly massive pack unless you do frequent long trips.
Basically the first gen electrics with 100miles or so range are probably the sweet spot for most people.
This was an excellent review of battery life and charging practices. Well done. I just bought my EV and was very stressed about the state of charging since I drive 65 miles a day and do not have access to a fast charger close to home. Thank you for sharing this useful information. 😅
Thank you! You’re very welcome!
i still have the 2011 first gen nissan leaf with 70% capacity left, i only slow level one charge up to 80% daily commute and about town for errands.
Do you feel some loss of power from motor? Anyway, congratulation for owning same EV for 12 years, amazing!
Very interesting, I have set mine for daily drive to 65% charge and discharge will land around 40% as I use about 25% on my daily commute. No degradation yet after 3.5k miles.
Great work to explain the study. I’m just wondering about the cycles to year calculation. If I discharge the battery from 80% down to 20% I need to charge it maybe once a week. If I use the range from 60% down to 40% I need to charge it maybe 2 times a week. So need more smaller cycles. Is then the number of cycles the battery can have before reaching the 90% mark for getting exchanged higher?
Thanks for the positive feedback Matthias! Think of it like this. Your battery leaves the factory with an published life of say 3,000 cycles. A "cycle" in this context means one transition from fully charged to fully discharged. So, you could get 3,000 full cycles from the battery or 30,000 "mini-cycles" of 10%. So what's the difference ? Both would yield the same mileage over their lifetime, right? Well cycles are one thing and maximum storage capacity is another. Let's say after a three years you need to go on a long trip. The full-cycle owner will notice that even when they charge to 100% the car doesn't go as far as it did when it was new. The mini-cycle driver will find his/her car still goes nearly as far as it did when new. Another complication is that a 90% - 80% mini-cycle is not the same as say a 60% - 50% mini-cycle. That's because at 90% the battery is under more stress internally, especially if it is left to stand at that SOC overnight. Therefore, if you only use 10% of your battery capacity each day it would be better to top up to say 60% and do that daily.
One thing, and probably the most important thing that wasn't covered is the total distance each different charging cycle would give you before it goes down to that red line you drew. How many kilometres of driving it reaches it. What you'll find is that there's very little difference. The difference is that with one car you're doing let's say 150,000 kms in 23 years but in the other car you're doing the 15,000 kms in 3 years. The thing that would make the biggest difference in the battery life is whenever possible, don't use those fast charges, unless of course you have to. It's like giving someone an X amount of free fuel. For someone who only drives 20 kms a day it will last then ten times longer than someone who travels 200 kms a day.
Great info to think about. It’s a similar discussion to how many kms should you drive before an ICE oil change for maximum longevity.
The only point I would add is that these cycles would have been done sequentially in a short timeframe so does not factor in calendar degradation. You may have a DoD of 10% meaning technically your battery will be at 90% after 20 years but calendar degradation would have also reduced your capacity possible at a rate of 1% or more a year. If you combine calendar degradation with cyclic degradation you will could actually find yourself under 70% capacity after the 20 years.
Please where did you find that optimal SoC is 50% as you are mentioning at the end of this video?
Thank you so much for putting this information out there.
No worries!
All wonderful theory. But.. a vehicles BMS handles a lot of this. Cars are now coming with 7 year unlimited km warranties, incl battery, so this might suggest the manufacturer has thought about what end users may or may not do. Limiting yourself so religiously to using such a small % of a battery is very counter to the whole driving experience and can become an obsession. There are so many variables indicated that affect battery longevity that you zero control over. Here in Australia, days and weeks go by where temps well exceed these "lab tests," and I would guess the same is true in European winter based climates where it goes below zero. The alternative to all of this science and maths, etc, is to enjoy the car you drive in the climate conditions that prevail for you and use common sense and manufacturers recommendations given they cover your warranty 😀
People want to keep these cars for way longer than 7 years, hence the video. Manufacturers care little about after warranty. It's like when they say only change the oil every 20,000 miles. They want the car to die after warranty expires. Although Tesla battery packs are lasting 420,000 miles from 2017 cars and growing. Refurb packs I wouldn't trust from earlier cars.
Remember as total charge drops the cycle capacity also shrinks. They should normalize their data to full cycle discharges. So a cycle from 75%-25% is only half a full depth of discharge cycle.
I was also told about every 3 months or so I should let the battery go low 10% or lower then charge back up to 100% just to keep the cells all active .Most of the time I have been charging from 50% to 80% I can easy change to 30% to 60% . Thank you.
That should only be applied to LFP batteries.
I purchased a new 2013 Chevy Volt. The battery size is 16.5 KW. It automatically had a built in buffer for high & low charge cycles. No confusion, no questions, just plug it in and walk away. That is the way all EV's should be. Plug it in and don't worry about it. The manufacturer should set the parameters. They set the warranty.
Legislation sets the warranty.
The US Federal government requires manufacturers to offer an eight-year/100,000-mile warranty on all EV batteries. California does one better, mandating a warranty of 10 years or 150,000 miles.
The European Union, as well as the United States, China, the United Kingdom, Japan and South Korea, have reached an agreement under the UN World Forum for the Harmonization of Vehicle Regulations bill, car manufacturers must guarantee that batteries may not lose more than 20 percent capacity in five years or 100,000 km (whichever comes sooner). After eight years or 160,000 km, the degradation should not exceed 30 percent.
Manufactures using NMC should know the mean live span and inform their buyers.
LiFePo4 is now the majority of BEVS so they will outlast an ICE with abuse.
@@waynerussell6401 What they don't tell you is that if the traction battery is replaced under warranty, it does not mean you're getting a brand new battery pack. More than likely you're getting a reconditioned pack. And I doubt the new warranty is for another 8 yrs/100k miles. I don't expect the sales people to know about the charging parameters of the car, but the manufacturer should state the guidelines. It shouldn't be quesswork.
Ternary Lithium Batteries (NCM and NCA) should normally be operated around the 50% capacity level. An example of this is when your daily round trip only requires you to charge the battery up to 60% when you leave home, and the battery drops to 40% when you return. So the battery is only cycling around the 50% of full capacity. If you keep doing this regularly, then your battery degradation will be practically immeasurable for a very long time.
Interesting stuff, thankyou. Question though; if you use the “best” data line and charge from 65% to 75% range daily won’t that count as a “cycle” and give you let’s say 30 miles for 1 cycle? (My Ioniq5 gets about 30 miles per 10%)
Someone who charges from 10-90% zone will have 240 miles per cycle. So even though his battery will last fewer cycles, he will perform a charging cycle much less frequently and perhaps get the same mileage life from his battery.
Guess I’d like to see the data results presented as miles of service rather than # of cycles. Does the data show that indeed your battery lifetime “miles” will be optimized by useing a zone such as 65-75%?
Hi, in normal circumstances a battery "cycle" is deemed to be one full charge to one full discharge. So if you only take 10% of energy from the battery it is 1/10th of a cycle. Do that 9 more times and you have completed a cycle. The most important reason for doing it this way is to avoid topping your battery to a high SOC (say 90%) each day and then leaving it at that level overnight. There is no point if you are only needing 10% the next day and in fact it will shorten the battery life.
Thank you. That definition of a “cycle” is really important
Complicated further by ambient charging conditions (real world), different charging rates, and calendar aging.
Good info nonetheless. Thanks for posting.
Thank you for the work you did here.
No worries!
My policy has been only charges fast as you have to and don't let the battery sit at 100%, but also do what you have to. With my 23 bolt EV I'm going to lower my Max from 200 or 180 charging every other day to 160mi, charging daily. I charge at 16 amps because I have the time
Very informative, thank you, I just bought a new ev on a lease so battery life is not too much of an issue, but i would like to buy a used ev after my 2 year lease, I do 15 miles per day so looking forward to a very long lasting battery when I buy one, the lease gives me time to decide which vehicle to buy and weigh up the pros and cons of Ev ownership 🙂
Very interesting presentation. I have a polestar 2 but I'm not sure of the battery chemistry. Is it the same as your Tesla as if so I will seriously consider doing the same as you as I only do short journeys too. Could you let me know please?
Thanks! I believe it is the same chemistry (NMC) but you'd be best advised to ask Polestar.
😢 in the small print of Tesla warranty on the battery, is written that if you not mostly charge to 80 % the 8 years warranty is void.
My friend had to buy a new battery after 4 years.
Curious, why did you decide to not top off each night? We have been the same as you with our Tesla but I had read somewhere adding frequently small amounts of charge 10% (50-60 SOC) was better than waiting two nights and adding 20% all at once.
Some brands need to be plugged in every night for the BMS to work effectively. This isn't an issue with Tesla. It was hard for me to plug in when I made this video because I was living in an apartment. Now I live in a house and I plug in every night.
One thing to note here is that a CYCLE is not "A charge" instead a cycle is 0-100% state. So if you charge from 50-75% that is not a full cycle but 0.25 of a cylce...
My 2021 Toyota Rav4 Prime has about 50 EV miles as a Plug in Hybrid electric. Currently I programmed it in the car to charge up to 100% based on current state of charge by 7:30 AM so that when I head off to work it's only above 80% for a limited time. I was considering also putting my charger on a power timer of some kind so that I could program it to shut off 30 min early and basically land me around 80% state of charge assuming a full charge is 2.5 hours or 150 min. Any thoughts if this would be a huge difference considering that I'm already limiting the time I'm above 80% before driving anyways?
For my other Lithium Ion battery devices I also try and avoid pushing the extremes all the time and it seems to have helped. My iPhone 13 is still at 95% max capacity after 2 years and based on a bit of research they say the average reduction in capacity for most people ends up being 5-10% losses per year. For my electric hydrofoils I usually store them at 60-80% state of charge and then top them up right before going out for a ride on the water. Once I get back home I charge them back up to that same 60-80% range. I feel limiting the time they spend above 80% or below 20% can really make a difference and is best for the longevity of the batteries. 🔋🔌
Yes although my understanding is 100% is not 100% as displayed in your car (there is a reserve top end to help battery life) in the Toyota's and most EV's
Thanks for that interesting information. And .. saw your T-Shirt of The Smashing Pumpkins and thought, well that's something from my youth and find some good old songs again on youtube. Sad that I can only give you one Thumbs Up instead of two :)
it is not only a battery concern, but actually charge efficiency. when you go above 95% you may have alow charge effieiciency such as
It looks like the best one is actually 75% to 25%. You just don't charge it as often, and you end up with the maximum available energy over the lifetime, doing some curve fitting to the data, looks like maybe around 75% to 30% would be ideal.
75-25 indeed is the sweet spot. Yes 10% DOD has lot more cycles but it only produces 1/5 energy of that of the 50% DOD (as in 75-25)! The term is equivalent full charge cycle. 75-25 is 1/2 of a equivalent full charge cycle. and 60-50 is only 1/10th of a equivalent full charge cycle. Comparing total kwh output, then 75-25 is pretty much spot on as the max strategy.
Another factor is battery preconditioning happens on a tesla every time before a charge. a 75-25 strategy saves a lot of battery preconditioning which saves power.
Folks - according to the number presented, charge 10% per night is NOT it.
@@manatee123Thank you! I had the same question.
Then I’ve heard, without any evidence to back it up, that EVs “like to be plugged in” - what’s that about? Just to prevent the battery from getting too low?
It would be great to know exactly where this 3,92 Volts point is located in the actual calibrated % level of the car. Some people say it's as high as 75% a majority say its between 65 and 70% and some like you locate it as low as 60%. It would be interesting to have a verified answer on this. Also it's important to note that we should hover around this 3,92 V point, not charge only up to this point, this means 3.92 V should be the CENTER of the ups and downs. If we use each day 20 points, we should charge 10 above and allow discharge 10 points below that point.
It's different for every car. You can monitor cell voltage with OBD diagnostic tools.
Each individual LiIon cell is flat at 3.3v or below and fully charged at 4.2v
@@bomberaustychunksbruv4119 this is an oversimplification and not true for LFP. In real life and if you plan on using you battery for years you NEVER go to 4.2 V. (and for LFP you NEVER go to 3.65 V. I have a DIY home battery made of all recycled used cells, it has a 8S LFP part a 7S NMC part my 100% maximum for NMC is 4.00 V and my 100% maximum for LFP cell is 3.5V, overall the pack triggers and alarm if it passes 28.1 V. My logic is good because I cycle this since 2014 and it remain very strong capacity. If you charge a drone battery that will have a short life you can go to 4.20 V.
When you say "storage is not going to be an issue for us since we're pretty much driving our cars every day", I'd suggest that every moment the battery exists is "storage time", never mind not driving. In my opinion ambient temperature is the #1 issue for those that go the extra mile to care for their EV battery.
My understanding is that a charge cycle is when a 100% of battery capacity has been charged, not necessarily in one charging session. Example; If I charge from 47% to 80%, I've charged 33%, and that would be 1/3rd of a cycle. And if you charge from 65% to 75% every day, it takes 10 charging sessions to have 1 charging cycle. Am I wrong?
No you are not wrong and that is entirely consistent with my pinned note. Thanks!
That is the number of discharges before the battery gets to 70% of capacity, not to a destroyed battery. Isn’t that what it says? Battery Management System will take care of everything.
Time at max or min charge, is equally important as the charge level. In other words, don't leave your battery charged at a higher charge level or a lower charge level for a long period of time.
I don't have an EV but setting the max charge cutoff point at 90% and start charging only when battery drops below 50% should be a great compromise as the 2 biggest battery killers are heat of which more is generated when a charging battery is reaching full capacity and frequency of charge/discharge cycles.
It works for my laptop battery which is now 5 years old and still has excellent battery health.
Thank you for the very interesting video. Two questions:
1. Is the same rule applies to modern mobile phones? (iPhone, Samsung, etc)
2. 10% DoD is 6000 cycles from 0 to 100% or from 90 to 100%?
Excellent info, thanks !!
No worries! Thanks!
If a person only discharges from 75% to 65% then they would likely charging every day, meaning that 9000 charge cycles / 365 is 24 years; however, a person who discharges from 85-25% likely only charges once per week, so that would equate to 2000 / 52 = 38 years. When you calculate the number of charge cycles remember to also include the time between charges.
A factor that will vary greatly for EVs when rapid charging (Supercharging) is the capability of the battery management and cooling system. The reason that degradation can be increased with an increased frequency of rapid charging is because the battery pack is heated up significantly by the process. Some car brands (notably Tesla) have sophisticated and responsive cooling control which maintains moderate temperatures within the pack (thereby reducing degradation) during rapid charging ... other brands have systems or varying capability and some don't have active cooling at all. Beware the consequences!
It's good to know but the problem is I think car manufacturer already set 80% as 100% in their software. So when you're charging up to 100%, it is actually 80%. Users didn't know about this and start charging to 80% which mean they're not using the the total capacity of their battery.
A great summary thanks Mark
No worries! Thanks for the positive feedback.
If battery is preconditioned it does not damage from fast charging. There are charts online that compare battery degradation of Teslas that are often supercharged and others that are rarely supercharged. The degradation is almost identical.